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Potato Growing Problems: Troubleshooting

Plant potatoes in early spring after the danger of frost has passed. Use disease-free seed potatoes.
Potato plants growing
Plant potatoes in early spring after the danger of frost has passed. Use disease-free seed potatoes.

Potato growing success can be had with well-drained, deep, sandy loam containing plenty of humus paired with cool, moist conditions.

Plant potatoes in early spring after the danger of frost has passed. Use disease-free seed potatoes; cut each potato so that two eyes are on each piece.

Even under these ideal growing conditions, potatoes are not always problem free.  Potatoes are susceptible to a host of setbacks.

Here is a list of possible potato growing problems matched with cures and controls:

Potato Growing Problems and Solutions:

• Plants do not emerge after planting seed pieces. Most store-bought potatoes are treated to prevent sprouting. Plant only certified seed potatoes. Cut seed potatoes when sprouts form, two eyes on each piece, and plant immediately. Plant when the soil has warmed to 45°F or greater.

• Plants are eaten or cut off near soil level. Cutworms are gray grubs ½- to ¾-inch long that can be found curled under the soil. They chew stems, roots, and leaves. Place a 3-inch paper collar around the stem of the plant. Keep the garden free of weeds; sprinkle wood ash around the base of plants. Use oakleaf mulch. Companion plant tansy between rows.

• Large holes in leaves, leaves and shoots are stripped. Colorado potato beetle is a humpbacked yellow beetle ⅓ inch long with black stripes and an orange head. Handpick off beetles. Keep the garden free of debris. Spray with a mixture of basil leaves and water. Companion plant with eggplant, flax, or green beans.

• Young sprouts fail to grow or die back. Blackleg, black scurf, or frost damage. Blackleg is a bacterial disease which leaves sprouts rotting at soil level–“blacklegs.” Black scurf is a fungal disease; stems will have brown sunken spots below the soil level. Remove infected plants and destroy infected tubers. Frost damage follows a frost; wait until after the last frost to plant.

• Leaves are yellowish and slightly curled with small shiny specks. Potato aphids are tiny, oval, pinkish to greenish pear-shaped insects that colonize on the undersides of leaves. They leave behind sticky excrement called honeydew which can turn into a black sooty mold. Spray away aphids with a blast of water from garden hose. Use insecticidal soap.

• Tiny shot-holes in leaves; small bumps or corky spots on tubers. Flea beetles are tiny bronze or black beetles a sixteenth of an inch long. They eat small holes in the leaves of seedlings and small transplants. The larvae feed on tubers. Peel away tuber damage. Pick beetles off plant. Spread diatomaceous earth or wood ashes around seedlings. Cultivate often to disrupt life cycle; spade deeply in early spring. Keep garden clean

• Leaves are chewed. Blister beetles are long, slender reddish-bronze colored beetles with red-coppery legs that feed on leaves. They secrete oil that can cause the skin to blister. Wear gloves and handpick them from leaves and destroy.

• Coarse white speckling or stippling on upper surface of leaves; leaf margins turn brown; leaves appear scorched and wilted. Leafhoppers are green, brown, or yellow bugs to ⅓-inch long with wedge-shaped wings. They jump sideways and suck the juices from plants. Use insecticidal soap. Cover plants with floating row covers to exclude leafhoppers.

• Leaves turn pale green, yellow, or brown; dusty silver webs on undersides of leaves and between vines. Spider mites suck plant juices causing stippling. Spray away with a blast of water or use insecticidal soap or rotenone. Ladybugs and lacewings eat mites.

• Leaves are mottled and become crinkled. Mosaic virus is transmitted by aphids. Control aphids with pyrethrum or rotenone. Plant disease free seed potatoes. Plant resistant varieties: Chippewa, Katahdin, Kennebec, Monona, and Snowflake.

• Gray blotches on older leaves; tunneling in leaves. Potato tuberworms are small caterpillars, the larvae of a moth that lays eggs on foliage. They tunnel through interior of leaves. Handpick and destroy. Hill up soil over tubers to keep worms from reaching tubers.

• Plants are green topped, no tubers. Temperatures are too warm. Potatoes require cool nights below at about 55°F for good tuber formation. Plant so that tubers mature in cool weather.

• Spindly cylindrical stems. Witches bloom is a virus disease transmitted by leafhoppers. Stems are elongated and plants set many small tubers. Plant is mostly leafy growth; leaves roll up and have yellow margins. Destroy diseased plants. Plant disease-free seed potatoes. Control leafhoppers.

• Stems have irregular dead streaks. Manganese level in acid soils may be high. Test the soil. Apply lime if manganese level is high. Grow resistant varieties: Canso, Green Mountain, McIntyre.

• Plants stunted; yellowish-black streaks inside stems. Fusarium wilt is a soil fungus that infects plant vascular tissue especially where the soil is warm. Fungal spores live in the soil. Remove and destroy infected plants. Rotate crops. Plant certified disease-free potatoes. Plant resistant varieties: Irish Cobbler, Kennebec.

• Leaves turn yellow and then brown from the bottom up; plants lose vigor; plants appear stunted; stems, roots, and tubers have tunnels. Wireworms are the soil-dwelling larvae of click beetles; they look like wiry-jointed worms. Check soil before planting; flood the soil if wireworms are present. Wireworms can live in the soil for up to 6 years. Remove infested plants and surrounding soil.

• Leaves yellow between veins; leaf margins brown and curl upward; stem base becomes dark brown, black, and slimy; tubers become slimy brown-black at stem end. Blackleg is a fungal disease. Add organic matter to planting bed; make sure soil is well-drained. Plant certified disease-free potato tubers. Rotate crops. Cover seed potatoes shallowly for quick emergence.

• Leaves and stems have irregular grayish brown water-soaked spots or rings; gray-white growth appears on the underside of leaves. Tubers have brown-purple surface scars; tubers rot in storage. Late blight is caused by fungus that infects potatoes, tomatoes, and other potato family members. It favors high humidity and temperatures around 68°F. Keep the garden free of all plant debris and avoid overhead irrigation. Remove volunteer potatoes before planting. Plant certified seed potatoes and resistant varieties such as Kennebec, Cherokee, and Plymouth. Keep tubers covered with soil. Cut vines 1 inch below the soil surface and remove vines 10 to 14 days before harvest. Do not harvest under wet conditions.

• Young leaves fail to enlarge, new leaflets roll upward and turn reddish purple color, or topmost leaves, become yellow. Potato purple-top wilt is synonymous with aster yellow; it is a viral disease spread by leafhoppers. Plant certified disease-free seed potatoes. Remove and destroy diseased plants. Keep the garden clean of plant debris. Control leaf-hoppers.

• Lower leaves cup or roll, lose their dark green color and become streaked and leathery; brown speckling at the stem end of tubers. Potato leafroll virus is transmitted primarily by aphids. Control aphids. Remove diseased plants and weeds. Spray with pyrethrum or rotenone. Plant certified seed potatoes. Do not save potatoes from infected crops. Plant resistant varieties: Cherokee, Houma, Merrimack.

• Leaves curl upward: older leaves turn yellow, then brown; young leaves show purple margins. Nodes and petioles are enlarged. Tubers may be visible. Plant may turn brown and dry. Potato psyllid is light gray-green to dark brown or black winged insects about the size of an aphid; they are flat and disk-like before plumping up at maturity. They inject a toxin into leaves as they feed causing the plant to yellow. Use yellow sticky traps to control psyllid.

• Tiny bumps on tubers, brown spots on tuber flesh. Nematodes are microscopic worm-like animals that live in the film of water that coats soil particles; some are pests, some are not. Pest root nematodes feed in roots and can stunt plant growth. They are more common in sandy soils. Rotate crops. Solarize the soil with clear plastic in mid-summer.

• Leaves yellow and margin roll; plants are stunted and dwarfed; tuber is malformed and cracks. Potato yellow dwarf virus is transmitted by leafhoppers. Destroy diseased plants and control leafhoppers. Plant disease free seed potatoes.

• Leaf tips and margins yellow, gradually brown and die; tubers have irregular brown spots throughout flesh. Lack of moisture or inconsistent moisture during hot, dry weather. Place 2 to 3 inches of organic mulch across planting bed to conserve soil moisture. Deep water potatoes 2 to 3 hours at a time; do not water again until the soil has dried to a depth of 4 to 8 inches.

• Older leaves yellow and die; brown streaks on lower leaves stems split lengthwise; stem end of tubers discolored around eyes. Verticillium wilt is caused by a soil fungus. It favors cool soil and air temperatures. Avoid planting where tomatoes, potatoes, peppers, eggplant, and cucumber family plants have been recently growing. This disease is most evident in hot weather when the plant is loaded with fruit and water is short. Plant resistant varieties: Houma, Cariboo, Red Beauty. Bacterial wilt also can cause these symptoms; black-brown ooze seeps from cut stems.

• Tubers have brown streaks and roots are growing from inside tubers. Nutsedge is a perennial weed that grows in many potato growing regions. The weed’s rhizomes will penetrate potato tubers. Keep potato plantings free of nutsedge. Nutsedge tends to grow in areas that are not well drained.

• Leaves turn light green, wilt, then dry; tubers turn watery and brown. Plants and tubers exposed to hot sun and dying winds after cloudy weather. Screen plants during extremely hot weather. Do not leave tubers in hot sun.

• Pink areas around eyes of tubers. Pinkeye occurs on tubers in wet soil. The cause of pinkeye is not known. Plant in well drained soil.

• Marble-sized potatoes grow directly from potato eyes. Cell sap is concentrated in tubers. Store seed potatoes in a cool, dark place. Plant seed potatoes later in season.

• Stems at soil level are covered with purplish, dirty grey fungus; foliage curls, turns pinkish to yellowish; dark brown or black masses on tubers. Black scurf or Rhizoctonia is a fungal disease that favors warm soil. Remove infected plants and plant debris that harbor fungal spores. Rotate crops. Be sure transplants are not diseased. Rotate crops regularly. Solarize the soil in late spring or summer. Black scurf is resting spores; peel away spores before using the potato.

• Irregular black and brown spots to ½ inch in diameter appear on lower leaves and stem; leaves turn yellow to brown; tubers may have brown, corky, dry spots. Early blight is a fungal disease spread by heavy rainfall and warm temperatures. It is seen near the end of the season when vines near maturity. Keep weeds down in the garden area; they harbor fungal spores. Destroy infected plants. Avoid overhead watering.

• Leaves yellow between veins and leaves curl upward; shoot tips are stunted; cut stems reveal a white ooze; cut tubers reveal a yellow to light brown ring of decay. Bacterial ring rot. Discard all infected tubers and plants. Plant certified seed stock; plant whole small potatoes instead of seed potatoes. Practice crop rotation. Plant resistant varieties: Merrimack, Saranac, Teton.

• Rough, scabby or corky spots on surface of tubers. Scab is caused by soilborne bacterium. Disease can be cosmetic. Modify soil to a pH of 4.8 to 5.2; work sulfur into the soil to make it slightly acid and reduce disease. Plant resistant varieties: Alamo, Arenac, Cherokee. If scab occurs, change varieties next year. Use long rotations.

• Green tubers. Tubers have been exposed to the sun during growing or after digging; sun causes tubers to form chlorophyll green spots. Keep growing tubers covered with soil. Do not eat green sections of potato tubers they contain toxins; cut away the green sections before using. Store potatoes in complete darkness.

• Tubers are knobby-shaped. Inconsistent moisture, erratic watering, alternating wet and dry conditions. Tuber growth is uneven. Keep soil evenly, moist. Slow, deep water for 2 to 3 hours; do not water again until the soil has dried to a depth of 4 to 8 inches. Mulch to conserve soil moisture. Plant potatoes closer together. Avoid planting knobby varieties.

• Cavities at the center of the potato, hollow center. Hollow heart occurs when potatoes grow too fast because as a result of too much water or too much fertilizer. Cavity can be discolored and lined with powdery decay, verticillium fungus. Cut away the brown areas before using. Fertilize plants early when tubers are about to form. Avoid planting varieties that develop hollow heart: Chippewa, Katahdin, Mohawk, Irish Cobbler, Sequoia, Russet, White Rose.

• Large shallow hole in tubers. Grayish white grub is the larvae of the Japanese beetle, a shiny metallic green, copper winged beetle to ½-inch long. Grubs feed on potato tubers. Cut away damaged areas and use the rest of the tuber. Handpick grubs and beetles. Use pheromone traps to control beetles. Spray with pyrethrum or rotenone.

• Rotten tubers. Bacterial soft rot enters tubers wounded by tools insects or disease. The vascular bundles in leaves, stems, and tubers turn black and bad smelling. Rot can not be cured. Plant potatoes in well-drained soil. Remove and destroy infected tubers. Remove all plants and plant debris at the end of the season. Promote good drainage by adding aged compost and organic materials to planting beds. Avoid over-head watering. Rotate crops.

Sulfur applied to the garden may reduce rots. Protect tubers from injury.

Potato Growing Success Tips:

Planting. Grow potatoes in full sun. Potatoes require well-drained soil rich in organic matter. Prepare planting beds with aged compost. If drainage is an issue, plant potatoes in raised beds. Plant seed potatoes grown specifically for crop growing. Keep the base of potato plants and tubers shielded from light and pest injury; use soil or mulch to cover plants. Plant seed potatoes in a 4-inch-deep trench and cover the seed with 2 inches of soil; as the plants grow continue to hill up loose soil around the plant eventually mounding the plants. An alternative planting method is to set seed potatoes on the soil surface and cover them with mulch–shredded leaves or straw. Continue to add mulch as plants grow through the season always keeping tubers well covered. This method can be used where the soil is heavy, clay-like, and not well-drained; however, the yield will be less.

Planting time. Potatoes grow best where the soil temperature is at least 50°F. Potatoes are usually planted in spring as early as 3 weeks before the last expected frost. Planting time can vary to avoid hot, dry conditions and to minimize disease and pest problems.

• In cooler summer regions, plant one potato crop in mid-spring for late summer harvest.

• In moderate temperature summer regions, plant one crop in late spring or midsummer for fall harvest. If you plant in midsummer, choose an early harvest variety.

• In long warm and humid summer regions, plant three crops: one in late winter for late spring harvest; a second fast-maturing crop in mid-spring; and a third late summer crop for a fall harvest.

• In regions where there is little or no frost, plant in fall when the heat subsides for a late spring harvest (plants will go dormant in winter and begin growing again in early spring).

• In mild winter and desert regions, plant in the fall for spring harvest, or plant an early-harvest variety in early spring.

Care. Potatoes are shallow rooted and require consistent, even watering from planting time until tubers are fully developed. Do not let the soil go dry during the growing season. When the foliage starts to yellow at the end of the growing season, stop watering so that the tubers do not rot. Keep tubers well covered with soil or mulch from planting to harvest; light, temperature fluctuations, and exposure are responsible for many potato disease and pest problems. Crop rotation will shield potatoes from many soilborne diseases and pests.

Harvest. Harvest “new potatoes”–young, small tubers–when plants are blooming; lift the full plant and its tubers. Mature potatoes can be harvested when vines die back on their own; if vines do not die back, cut the vines at soil level 2 weeks before you want to lift the tubers–this will cause the tubers to harden.

More tips: How to Grow Potatoes.

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182 Comments

  1. I have red and white potatoes and they have little green fruit on the stems. And the plants are just about 5′ tall.Can you answer my question on what these little fruit berries are? Tks! Jo Ann

      • Potato plants can be hilled; hilling means the soil is mounded up around the leaves periodically during the season–leaving just a few leaves visible above the soil; this is a common procedure to grow more tubers.

        • Although this form of hilling is a common procedure, I have read a compelling article arguing that it does not produce more tubers due to the science of tuber formation. Basically, although adding soil will produce new adventitious roots, only the roots in the first few inches above the seed potato will produce the stolons which make potatoes. Article here: https://www.cultivariable.com/potato-towers/

      • I’ve heard that potato plants tend to do this, and when grown outdoors on farms they are often left to grow on the ground like this since it doesn’t cause enough problems to solve. You can stake them to keep them upright though–this is what I’m doing in my indoor setup under a grow light. (This is my first year growing potatoes. The variety I am growing is “Nemah,” which cannot be grown outdoors in my climate because it is a “short-day potato.”)
        The term for a plant falling over is “lodging,” which can be caused by excessive nitrogen or deficient phosphorous. I think lodging can also be caused by legginess (thin, stretched out, weak appearance) as a seedling, which I think is usually caused by insufficient light or lack of air circulation (the breeze triggers the plant to strengthen its stem instead of lengthening it).

    • Stephen Albert’s response is good, but I just want to add that the seed potatoes we normally use to grow potatoes are clones of their parents, so one always knows what to expect when growing them. True potato seed is different in that it produces a random, never-before-seen variety of potato with each plant–potato plant genetics prevent the seeds from “breeding true” the way many other plants do. You can start the plants using a similar procedure as you would for tomatoes in your climate. The most important thing is timing it so that the potatoes are transplanted in the ground no later than six weeks after germinating. Here’s an article for more information: https://www.cultivariable.com/top-10-beginner-mistakes-with-true-potato-seeds-tps/

    • Hi Ann,
      I saw a video on youtube that talked about potato berries. These are poisonous! They can be used to start potato plants the next spring since they contain seeds. The seeds will be the next generation of the potato plant the berry is from; unlike the seed potato which produces a clone of the plant that grew the seed potato. So the berry may produce a slightly different type of potato. The berries don’t grow every year or on every plant so enjoy them when you get them

  2. The green berries on your potato plants are the flowers gone to seed. The flowers have faded and the berries have taken their place. These berries are poisonous; do not eat them. You can harvest the seed from these berries and propagate new plants. But, most commonly seed potatoes–pieces of potato tubers–are used to grow a new crop.

  3. I have been growing potatoes in my allotment for 3 years,every year I plant a different variety however all the tubers when boiled do not hold their form and disintegrate.The other allotment holders all seem to have the same problem.
    Thanks Alan

    • Try planting a more waxy variety. Some varieties are too starchy to hold up to boiling. At the worst, you’ll have good frying potatoes.
      I don’t know what else could be doing that, I can’t think of a disease that makes them fall apart like that if it looks fine when you cut them

  4. Here are potato cooking basics:
    • High starch potatoes are used for baking, frying, and mashing. Cook high starch potatoes and they will have a floury, dry texture. High starch potatoes have thick brown skins. Idaho russets and Burbank russets are high starch potatoes.
    • Medium starch potatoes are all purpose potatoes. You can use them for steaming, baking, roasting, grilling, and au gratin dishes. The flesh of medium starch potatoes is moister than high-starch potatoes. Medium starch potatoes include Yukon gold, yellow Finn, and German Butterball.
    • Low starch potatoes are used for boiling, roasting, grilling, sautés, stews, salads, and au gratin dishes. When you cook low starch potatoes their moist, dense, waxy flesh holds together and keeps its shape. Low starch potatoes include California white potatoes, round white, and round red—sometimes called “new” potatoes.
    Many fingerlings—small finger sized-potatoes—are also low starch potatoes. Fingerling varieties include French fingerling, German fingerling, Russian banana, Ozette, and Ruby Crescent.

    • Lays and Wendy’s chipping and frying varieties are very waxy. It creates a better product.
      How to tell the starchiness of a potato is to slice it with a normal kitchen knife and see if it sticks. If it falls off, it’s waxy. It sticks firmly to the knife, it’s starchy.

  5. We grew three kinds of potatoes this year. One kind produced some tubers that will not cook. It has nothing to do with how they are cooked. I can sometimes tell that a particular potato is not likely to cook. When sliced across the middle, just under the skin there is an outer ring of potato that looks normal. Then the interior of the potato has a sort of translucent appearance with a more translucent branching type design. Do you have any idea what might cause a potato not to cook? I have searched the internet and found a few other people complaining of the same thing, though no one believed them, thinking that they were making a cooking mistake. It is not a cooking mistake! I will have 3 potatoes that cook and 2 that will not, all 5 being baked, fried or boiled exactly the same way. If I wait for the bad ones, the good potatoes get over cooked.

    • What you describe — the description of the layers of tissue below the potato skin — may be the result of inconsistent moisture uptake which has resulted in variations in cell development. Moisture uptake might be related simply to watering–watering not being evenly consistent; it might also be related to changes in the weather during the growing season–overcast days or chilly days that interrupted development of the tuber. Be sure to mound up your potato plants and protect them from variations in weather and temperature; as well mounding with compost should evenly regulate moisture uptake.

  6. We grew some red potatoes but they have almost blister looking spots all over so they don’t look appetizing. Can you tell us what went wrong?

    • I suspect you have potato scab–the scabs can be blister like or pitted. Potato scab can occur when the soil pH is too high; test the soil pH and adjust the pH to 5.0 to 5.2 (ammonium sulphate will adjust the pH down if your soil is alkaline). Be sure the soil stays just moist once tubers begin to form–too much soil moisture can result in scabs. Scab is a common tuber disease. You can still use the tuber, just cut away the scab.

  7. potato problem – can anyone help?
    Arran pilot spuds look fine when dug up, but however they are cooked, gently boiled, steamed, they fall apart n the pan and turn to mush! WHY? HELP!!

  8. My potatoes have rough scabby brown eruption spots. In the article above, it says this is caused by a soil borne bacterium. Are the potatoes edible, or should they be thrown away?

  9. Oh lord no, never cut your potatoes. Pick small ones and plant them whole. Even 14mm potatoes (about the size of a normal marble) will grow large, luxurious plants. But never cut a potato you intend to plant. The skin protects them from viruses and other diseases, damage to the skin compromises their immune system making them more likely to get sick.
    I was a harvester at a hydroponic potato farm. We had to know what harmed our charges so we could keep from making them sick.
    Leafy tops and few/no tubers could also be from excess nitrogen. If you have that problem, try planting them after your corn or use low nitrogen fertilizer when you fertilize. Some potato varieties are very sensitive such as the delicious Rose Finn Apple fingerling variety, that variety won’t do anything until later in the season anyway so it’s a good one to plant in summer for later fall harvests.
    Watery/squishy tubers could also be a disease. Tubers should be firm with a slight give when freshly picked with no discoloration or scabs. Remove any suspicious plants and eat the usable tubers just in case. Never plant a potato that has Scab, it will just transfer to the next generation and give you grief.
    Green potatoes are good to plant, they have more poison in their skin and resist disease better than the pretty purple, white, pink, red, and brown that you like to see on the dinner table.
    Cavities filled with fungus or decay is a disease.
    Wash your hands up to your elbows when you go take care of your plants or seed potatoes, have a pair of old sneakers to use in the garden that have been sanitized to prevent disease spread, bleach your tools after they touch sick plants, pick the blooms (pretty as they are, they reduce production. Use them as cut flowers if you want), and never eat their tomatoes.
    Happy planting.

  10. I have white crusty deposits on the leaf edges of my potato plants. The plants are healthy looking and came up a couple of weeks ago, so they’re only a few inches tall. We did just finish with a week of rain, but it doesn’t look like mildew. I haven’t found anything on the web as to what this stuff might be. Any ideas? I live in N. GA.

    • The white crusty deposits on your leaves could be a residue from salts in the soil or your irrigation water. Try gently rubbing the crust away between your fingers. Powdery mildew will not be crusty.

      • Thanks! The white disappeared so I do think you’re exactly right. Unfortunately, our potato vines are dying–the leaves appear to be sunburned and they shrivel up and die overnight. We dug into the soil and found no potatoes (planted in mid-February). The weather has been very warm here in GA (89 today) and the soil is very warm. No cut worms have been found. I’m thinking it’s too hot for potatoes?

        • Potatoes need a frost-free growing season of 90 to 120 days but they also grow best where the temperature’s are mild 60F to 70F. Hot weather will cut down on the production of tubers. Late winter or very early spring is the right time to plant in your region, but this year the hot weather came too soon for this crop.

  11. My early potatoes where forming flowers when I noticed the leaves where turning yellow in one line I’ve dug the whole line up and the tubers where rotten what has caused this and what else can I do as I’m new to the allotment

    • Yellow potato leaves can be a sign of Verticillium wilt–a bacterial wilt. That your tubers were affected all but confirms this. Verticillium spores can remain the the soil for up to 10 years and is nearly impossible to eradicate. You will have to replant, but before you do add plenty of compost to your soil and choose a resistant variety to replant.

  12. Hi!
    Ok so I have planted purple majesty potatoes and purple Viking potatoes… My Viking started flowering first, now my majesties are but on my majesties there are waxy shoots coming out of my mounts…… Should I be worried? Do I mound up some more? What do I do? Please help!!!!

    • Yes, mound up the soil or add mulch to cover the base of the plants. You can mulch with clean straw or leaf mold. Keep several inches of cover over the tubers.

  13. Once my plants have started wilting is there any saving them? I’ve pulled some mushy brown rotten slimy stems out. I suspect it’s the cucumber beetles that infected them. Do I dig them up and replant this late in the season? Should I just see if they survive? They are in tires above ground with a mixture of compost and pine soil. Is neem oil my only organic defense to the beetles?

    • If the stems have become rotten, the plants are finished. Pull them up. If you suspect cucumber beetles, you can cover your plants with light horticultural cloth row covers to exclude the beetles; you can place sticky traps near the plants; you can handpick and crush the beetles; you can use neem oil, but you must spray each beetle with the oil to kill them.

      • Thank you. So, I had to dig deep but I found the rotten mess. It was inside a root ball? Is that how I would find it? Or do I have something else going on?

      • Will neem oil as a soil drench harm potatoes? Will it give them an off flavor? If not? How much should I use to drench each plan with 18”+ stems?

        • Check the label of your neem oil product for a soil drench formula; the formula may vary by manufacture. Here is one formula: Use one teaspoon neem oil per quart or four teaspoons neem oil per gallon of water. To mix: (1) add 1 teaspoon of biodegradable dish detergent to a small portion of the water as an emulsifier; (2) add the neem oil and mix well; (3) add remaining water, stir well and use immediately. Again, read the specific directions on the neem oil label.

  14. I harvested about a dozen red potatoes and they have small white spots on them. Is that bad? Are they edible? We have had a LOT of rain. Not sure if summer will ever get here!

    • The white spots following rain may be a sign of early blight, a fungal disease. If the spots are pinkish that is a condition called pinkeye. Brownish purple spot is a sign of late blight. These diseases can be avoided if potatoes are planted in very well-drained soil. Once rot sets in the tubers and plants should be pulled up and destroyed. If the spots are corky or scab like you can peel and eat the affected potatoes.

    • Store only whole, undiseased potatoes whose skins are intact and not dinged or nicked. It’s best to let just harvested potatoes “cure” or dry in the sun or in a well-ventilated place for 7 to 10 days before putting them into storage–this will toughen their skins and keep them from shedding (usually due to too much moisture in the tuber). Clean the soil from the potatoes before curing. Store potatoes out of the light at about 45F.

    • Brown spots under the skin of the potato can be a indicator of bacterial ring rot; this can happen when the soil dries and then gets very wet, off and on; make sure you are growing your potatoes in well-drained soil–so that the soil is not too wet–and at the same time keep the soil evenly moist, do not let it dry out. The easiest way to do this is to grow potatoes in compost rich soil. Aged compost is well draining its particles hold moisture. Flea beetles can cause rough surface spots on potato tubers–the larvae feed on the tubers. You can cut away the rough areas and still use the tubers. Control flea beetles by covering your crop with a floating row cover and placing sticky traps nearby.

    • When potato tubers are deformed stress is usually the cause. Here are some suggestions to give your potatoes the best growing conditions: (1) plant in clod and pebble free soil; make sure the soil is light and well aerated; (2) avoid growing potatoes in weather too hot; temperatures above 80F/26C will lower the supply of carbohydrates to the tuber and decrease cell division, resulting in malformed potatoes; (4) keep the soil evenly moist–not too wet, and don’t let the soil dry out–especially during early growth and tuber development; (5) use a low nitrogen fertilizer, try 5-10-10; (6) give your plants plenty of room–don’t plant potatoes too close together–18 inches or more between plants will allow for tuber development.

  15. I have looked here for my problem, but I don’t see it; maybe you can help! This is my first time planting potatoes (backyard garden in Houston, TX) and when I picked up my first plant to see what it was looking like, I noticed it was “full” of water….. So much so that the skin had opened a little during the picking process and I could actually squeeze water out. I haven’t watered them overmuch and there hasn’t been all that much rain. Could it be the water table is just that saturated where I am? If so, how can I correct it? I suppose more soil, raised beds, etc, would be the solution. Just trying to get some additional information here. Thanks in advance!

    • Your soil may be holding too much water. Grow your potatoes in planting beds are compost rich; compost rich soil is well drained. Try amending your native soil with compost to 1 foot deep, then erect raised beds at least 18 inches tall over the enriched h=native soil; that will give you 30 inches of loose, well-drained soil, more than enough room to raise potatoes.

    • Leaves wilting can be a sign of too much moisture or not enough. Make sure the soil is just moist–not to wet, and not dry. Get an organic fertilizer 5-10-10 and feed the plants; follow the directions on the fertilizer package.

    • If the stem has been damaged, the plant will likely stop growing. Take up the potatoes that you have; they may be big enough to eat as baby or new potatoes.

  16. What could have caused potatoes to wilt and fall over. It seems like it was caused by the overwhelming heat and sun I guess cause the leaves are drying out and getting crispy and wilting and falling over and dying so I don’t think it’s a disease and I couldn’t find another reason for it to do that?

    • Make every effort to keep your soil evenly moist during the growing season. Aged compost is both well draining and water retentive, so it is a good addition to any garden planting bed.

    • Very hot temperatures can cause potatoes and other plants to suffer, wilt, and die. Keep the soil evenly moist during the growing season. When potatoes are ready for harvest, leaves at the top of the vine will begin to dry out and die. You can gently unearth the tubers to see if they are harvestable size.

    • Potato flower buds that hold on the plant without opening may be caused by environmental factors: (1) temperatures too hot–over 85F and certainly temperatures in the 90sF; (2) temperatures too chilly–below 55F; (3) rainy or overcast weather; (4) harsh winds; (5) inconsistent soil moisture–dry then wet. If environmental factors do not seem to be in play, the buds may have been touched by a fungal–which can cause buds to turn gray then dry up.

  17. Hello! This is our first year, upstate NY. We have Yukon Golds, planted 5/30, built in a box and we’ve added dirt and boards when needed. All of a sudden our top leaves have started wilting, our bottom stems and leaves yellowing, and the main stalk of the plant was broken beneath the soil. Also, our flower pods up too look like they’re starting to die off, without blossoming. We safely removed what soil we could to get a better look. We’ve found no cutworms, no wire worms, nothing out of the ordinary. Here and there I’ve noticed a few cucumber beetles, have noticed little orange eggs on the underside of leaves which we promptly removed. Yet, most of the troubleshooting I’m looking up doesn’t correlate with our plants. Thank you in advance for any insight you can offer. We really appreciate it.

    • If stalk of your potato plant was broken or roots severely disturbed, then the capillary system that takes water and nutrients up into the stems and leaves was likely severed; this would account for the die back. Once structural damage happens to the capillary system, there is little you can do to mend it. Other causes of plant die back are root rot, fusarium wilt, verticillium wilt and other blights. Again there is little you can do to save the plants. Make sure crops are planted in well drained soil in the future.

      Potato flower buds that hold on the plant without opening may be caused by environmental factors: (1) temperatures too hot–over 85F and certainly temperatures in the 90sF or greater; (2) temperatures too chilly–below 55F; (3) rainy or overcast weather; (4) harsh winds; (5) inconsistent soil moisture–dry then wet. If environmental factors do not seem to be in play, the buds may have been touched by a fungal–which can cause buds to turn gray then dry up.

  18. ***PLEASE help. First time potato grower, in Alexandria, VA. I’m so bummed. I made my own grow bags. I had three potato plants growing awesome! Then I mulched them with grass clippings. They must have been too hot. The plants were dead in a matter of less than a day. It looks like the heat of decomposition burned the stems. Does that make sense? How do I use grass clippings again without that problem??

    • In three days the grass clippings may have begun to decompose and the heat might have affected the stems–it is more likely that the grass clipping only began to rot and the rot spread to the plant stems. Avoid covering or burying the crown and stem of a plant with any mulch–moisture can collect and rot can take hold. In the future, allow the grass clipping to decompose in a separate container before adding them directly into the planting container.

      • I mowed my lawn and immediately put the grass clippings on the potato plant. By the next day the plants were wilted and dead. When I picked the stem up out of the soil/grass clippings, it was wilted where the grass clippings surroundced it.

        Here is my follow on question, when you add soil (or mulch or straw or grass clippings or whatever you are using) to a bag, after the plant has grown about 6-10 inches, I thought you were suppose to justy add it. Are you saying don’t let the soil touch the stem? How am I suppose to cover it then? I’m so confused.

        • Potato tubers develop on stolons growing from the lower stem of the plant–-not the plant’s roots. Because the potato tubers develop from stolons on the lower stem, you “hill up” or cover the tubers because they are developing above the roots and native soil level. (Hilling up keeps the tubers from the sun and “greening”–turning green from sun exposure–a poisonous alkaloid makes green potatoes taste bitter and they should not be consumed. When you hill up, you want to be sure that the material you hill up with is very well-drained–light or sandy loam, aged compost, straw or hay are the best choices. Fresh grass clippings are full of moisture–that is in the tissue of the grass blades–and is very moisture retentive–not fast or well draining. I suspect the fresh matted grass clippings–full of moisture–simply began to rot and the rot spread to the stem of the potato plant. Hill up or cover the potato stolons with dry or quick draining materials–you are hilling up to keep the sun from exposure to the sun.

  19. My healthy looking potato plants have grown well in a potato bag, but suddenly the plant stems are slumping. They have not yet flowered, and one of the otherwise healthy looking stems actually snapped. Should these be staked up?

    • Plant growth above the break in the stem is in all likelihood compromised; you can expect die back. If you have multiple stems then the plant will continue to grow. Staking up the broken stem is unlikely to mend the break in the stem’s capillary system. Other unbroken stems may be protected from damage by staking.

  20. I have potatoe plants. They are green and bushy and appear healthy every where but at the top. They are staying small and have what looks like a fine black dust on the new leaves but it doesn’t wipe off with finger. What is it?

    • A “black dust” that does not wipe off of potato plant leaves could be insect excrement–try washing the black away with water and dish soap; if it does not come off, you may have a fungal or bacterial disease. Trim away the infected leaves and wait for new leaves to grow back. If the all of the plant’s leaves begin to turn black, the plant may have a bacterial disease and should be removed from the garden.

  21. My Potato plants have all gotten curled up leaves. I assume from aphid virus. If I spray for aphids will the plant come back to life or should I remove them completely

  22. My wife and I recently started growing potatoes in a tower to save space as our yard is small. They started out fantastic, strong, thick green stems and leaves, now they appear to be dying. We have 2 different varieties planted in our tower: White and Purple. What could possibly be causing this? I don’t over water them and do my best to keep the bugs away. The stems and leaves went from a beautiful dark green to a now almost yellow with significant slumping. Any hep and advice would be appreciated. We live in Eastern Wyoming and it gets pretty hot during the day with overnight lows hitting mainly around the 60’s

    • High temps in the upper 80s and 90sF can set potato plants back. More serious problems include fungal blights and root rots–often caused by soil being too wet, not enough sun, or not sufficient air circulation. If you suspect a leaf fungus (it may be too late now) you can spray the leaves with 1 part baking soda to 9 parts water to inhibit fungal spore growth. Make sure the soil is very well drained.

    • By gutted, do you mean they are hollow inside? Potato tubers that are hollow inside. Hollow heart–as this is called–usually occurs when growing conditions abruptly change during the season, such as when potato plants suffer from too little water or not enough nutrition during development. The tubers react to environmental stress by growing too rapidly causing the tuber pith to pull apart or die.

  23. Our potatoes, grown in sandy soil, scrape well but when cooked have an outer ring of potato which goes mushy whilst the centre is still firm and not ready for eating, any ideas on what might be causing this?

    • A bacterial blight or bacterial soft rot or ring rot can cause potato tubers to rot. These diseases are often introduced by insects or disease that weakens the plant. The tubers will not be usable. Remove rotted plants to stem further spread of disease. Make sure that your planting beds are well drained–add lots of aged compost. Do not water overhead; water at the base of plants. Drench the soil with compost tea–which will add beneficial microbes to the soil. Use disease free or certified seed potatoes when planting.

    • No, what you describe is not common. Commonly, about 1 to 2 weeks after a seed potato is planted it will produce a main stem and the first leaves above ground. At the same time a root system develops and begins to absorb nutrients. In the next two or three weeks the leafy part of the plant continues to grow. After about five weeks the main stem of the plant stops growing and produces a flower bud. This usually indicates underground tuber development. The plant leaves produce food and energy which is used to for tuber development. The tubers (which we eat) are thick, short, underground stems.

  24. I just harvested my potatoes and they are almost clear, not white. They also do not taste good. I have grow new potatoes for 3 years now and never had a problem. These are organic seed potatoes bought at Lowes, this spring. I have always use potatoes I bought from the grocery store as seed potatoes and always have a great crop! Anyone have any Idea what happened?
    Thanks

    • Apart from where you purchased your seed potatoes and the variety, look to environmental factors that may have played a role in this year’s harvest results: was there more or less rain–more or less irrigation (improve drainage and moisture retention by adding aged compost); are the planting beds in a different location; was the weather overcast this season as opposed to last. A different result from the past is commonly related to environmental changes.

  25. I grew Russet potatoes this year, same as in the past. This year the potatoes are DRY when roasted, hard-then mushy when cooked. Seems to be a 1/4 inch layer that never cooks properly, I scooped it out of the boiled water.I never got that “new potato” taste. They are very dried out, and tasteless no matter how I try to prepare them. BBQ’d is So dry – can’t eat them.

    • Could the problem be cooking temperature? Set the oven at 400°F and then wash off the potatoes. Pierce the potato on both sides with a fork to let steam escape. Evenly space the potatoes on the oven rack–don’t bunch them together–so they cook evenly. Use one hour as your guideline for cooking. As the potato bakes you will start to smell the aroma; pull one out and poke it with a fork–if the tines go all the way in and the fork comes out nearly clean, the potato will be thoroughly baked. The potato interior temperature should be 185°F (use a meat thermometer) or greater–and it should be cooked evenly.

      • No, it was the potatoes, I threw the whole four rows from the garden out. They were just not good for some reason. I have been cooking for decades and have never had potatoes like this. Must have been bad seed, bad weather, or bad soil.

  26. I’m attempting to grow a potato plant indoors this winter for the fun of it. As it grew, I covered it, so soil depth is 18 inches. There are 2 shoots the are growing, however, they only continue to grow up and are at least 12-14 inches above soil. New growth continues but not getting bushy at all. Leaves every inch, whirled. Lower leaves browning. I have it in as much sun as it can get here in Northwest Montana. I feel like soil is moist, but not too wet. Trying to figure what it needs to grow more healthy and more vibrant. Ideas on what’s missing?

    • It sounds as if the plant is not getting enough sunlight–your description of the stems and leaves would suggest that the plant is leggy and stretching for light. Try using a grow light placed a foot or two from the top of the plant and give the plant 10 hours of light each day. You will know in a week or two if that is the solution.

      • So I got a grow light on it, a couple feet above, and it proceeded to wilt and yellow and looks very sick and poor. One stalk reacted within a day and the other took a few days. I removed it from the light, but no change. Do you think it’s too far gone t to produce new shoots? Should I continue to keep under the light and see if the plant can adapt? Should I cut off dying stalks? They’ve lost their color and rigidity. They are pale green to yellow and soft.

    • Potatoes are grown from other potatoes. New plants develop from sprouts coming from dormant buds on seed potatoes or a piece of a larger potato. The sprouts then develop into independent plants. It takes a week or two weeks for the main stem and first leaves to appear above ground. At the same time the root system is developing. For four or five weeks have the sprout emerges, the stem grows and leaves will develop. Energy from the leaves helps the plant produce tubers underground–this starts to happen about seven weeks after planting. An indication of tuber development is commonly flowering. As the tuber enlarges the skin gets tougher and the plant top dies indicating its harvest time.
      One plant can produce many tubers. It could be that after the plant top has died, you have found the tubers produced by the green plant that is now gone or decomposed.

      As potatoes enlarge underground, the outside layer of the tuber gets tougher and tougher, keeping moisture within the potato and protecting it from outside attacks by organisms that can cause rot.
      This toughening of the skin continues even as the plant tops die, the signal to the gardener that the harvest is at hand. Potatoes can remain underground for a little while after the tops die, so that the last energy in the tops can be transferred to the tubers. If the outer skins can’t be rubbed off after the potatoes have been dug, they’ll store well.

  27. Hi there,

    Hi there,

    I have 2 raised beds. One contained white potatoes and the other sweet potatoes. I planted the seeds back in the autumn and had hoped I could get them growing using a cold frame idea. It didn’t work. Much to my surprise as soon as the soil warmed up this spring plants popped up. First the potatoes and a few weeks later the sweet potatoes. They were looking fine but we’ve had a very dry April so one day I gave them a good dousing using a shower setting on the hose. The sun was out. Over the following days I noticed the mature leaves starting to look a little unhealthy. I thought perhaps a little scorching while watering had occurred as the leaves are quite hairy. The die back continued.

    It looks to me like I am going to lose both beds of plants. The red herring I am dealing with is that the neighbouring farmer sprayed glyphosate on the surrounding field the same week I watered them. No obvious dying off on the lawn surrounding the beds but wondered if potatoes take is up super readily compared to other plants? What is it likely to be? I can take pictures if I can share them on here? Thanks, Bill.

    • The ideal method to water young plants is with a soaker hose or drip irrigation avoiding water on the leaves. Young plants with shallow roots can be easily damaged if the soil goes dry and cell growth is interrupted. So it’s best to keep the soil just moist. The combination of the root zone becoming dry during the warm weather and leaf burn as a result of water sitting on young leaves on a sunny day may have been more than the young plants could handle. Glyphosate drift could also affect young plant (the potato seedlings) tissue more quickly than older plant tissue (the grass). You might want to simply wait a week to see if the young plants can bounce back.

      • Hi Steve,

        I appreciate your reply. They have made a slow comeback by the looks. I’ll endeavour to keep them just moist and see how I go. I’m hoping it was a combination of what you’ve mentioned and a late frost. The glyphosate option scares me! We certainly experienced some drift on a hedge further up the garden, perhaps about 40 feet away. The spuds would have been down wind.

        Thanks for your advice.

  28. Hello, this is my first time growing potatoes and I have found this page and all the comments very helpful! I am growing potatoes in a bag and they have been growing extremely well. The issue is that some of the plants are growing faster than others. I have some that are 12 inches above the soil and some that are 5 inches. Since they are all in the same bag it is not possible to mound them separately. Should I just mound as high as I can on the lowest plant and not about the taller ones?

    • Yes, mound the soil up to the top of the lowest growing plant; the taller one will likely be productive. The growing experience you gain this year will be of great help to you next year.

  29. Anybody know what the small bumpy little red spots on potato plants are? Been driving me crazy trying to find out what they are. They are under the leaves. There red, not brown.

    • Red spots on potato leaves: if you are certain that the spots are not insect eggs then treat the spots as a fungal disease. (If the spots are eggs or insects, you will be able to crush them between your thumb and forefinger.) To treat thee plant for a fungal disease, spray with a organic commercial fungicide or neem oil, or spray the plant with compost tea to slow the development of fungi spores. For a certain diagnosis, place infected leaves in a plastic baggie and take them to a nearby Extension office.

  30. I freaked out when I dug some potatoes early that had little white dots on them. I put them in the house and by noon the dots were GONE. The dots are the openings in the skin that open when the potato is too wet. Not too wet to eat or survive, but too wet to water more. I just dug all my crop out of the mud after 5 inches of rain and the Dots on them disappeared.

  31. This is my first year attempting to grow potatoes. I live in an apartment where everything must fit on my patio. Because of this I decided to go with container planting so I could still give it shot. I have two bags one with Kennebec potatoes and one with Katahkan I believe. I cut two tubers each in half and planted a total of 4 pieces in each bag. They have been outside for about 2 weeks now and 2 pieces from each container have reached the top but one bag has 2 pieces that are just barely about soil level and the other has one just above soil level and one that hasn’t broken the surface yet. I know I am supposed to add soil the the container once they reach a certain height but I am unsure how to mound the tall plants without the soil falling down and covering the ones that are not all far along yet. Any recommendations?

    • In the garden you can mound soil up around the growing stems of potatoes. If the containers your potatoes are growing don’t allow for mounding the soil, you can mound up straw around the plant just leaving the top leaves exposed. Potatoes will form in the straw mulch.

  32. For the past three years we have tried to grow potatoes, and have had the same issue. We plant the seed potatoes, and as they grow we add soil. We usually add the soil three times, and everything appears to be fine. Then the fourth time we add the soil the plants die back. The tubers are usually small. We have tried growing them in a potato bag, in a wooden raised bed, and now in a metal horse trough. The result is the same.

    • The plants may be finishing there life in due course–that is they have grown the number of days to maturity and are finished. The small tubers may be the result of soil too rich in nitrogen. Use an even complete fertilizer such as 5-5-5. Note the day you plant and count ahead the number of days to expected maturity. Whether the tubers are large or small, the plant will begin to die back in its genetically programmed time. Using a low nitrogen fertilizer you should get the green leaves you need and larger tubers. You can err on the side of higher phosphorus and potassium.

  33. I pulled a single potato out of my garden to check progress and it appears to not have any skin on it. Is that because I pulled it too early? Or is something wrong? Is it safe to eat?

    • Yes, you likely pulled the potato a bit early before the skin formed and started to harden. New potatoes are very thin skinned. If the soil has not pathogens, the potato will be safe to eat.

  34. So we have our first crop of fingerlings growing, the plants are huge, and green, and growing very well. We are about day 100, and we tried to dig up a plant to check and all we see are long white tubes, but no potatoes yet! I am guessing they arent done yet or its too hot (utah high 90s). Got any further advice? Watering well in raised beds, fertilized as needed, covered hills 3 times…help

  35. ick, some of my purple potatoes, still in the ground, are half white slime, next plant over is fine, I’m in Zone 5 in western Massachusetts. I’ve planted potatoes in same plot just once before and I did plant cut pieces, not whole. Never saw this slime before.

    • The likely cause of the slime on your potatoes is bacterial soft rot (Erwinia). This bacterial disease is in the soil and can enter tubers through nicks or cuts or even natural openings in the skin. Inspect each potato and discard any infected tuber or any questionable tuber. Those uninfected can be used. A second possible cause is potato late blight (Phytophthora infestans), a fungal disease. Potato late blight is commonly marked by leaves turning black as well. Both of these diseases can live on in the soil after harvest so be sure to plant potatoes in a different location next season.

  36. our plant growth normaly then after 80 days the leave start to be yelow after few days the seeds start to spoils, please could help me in this issue why it happens?

    • Potato leaf dieback is usually a sign that tubers are maturing beneath the soil; check to see if your potatoes are ready for harvest. You can check tubers earlier and harvest them at fingerling size and not wait for them to mature. Other potential causes of yellowing leaves could be insufficient soil moisture, weather too wet, temperatures too hot or too cold, and too much nitrogen added to the soil.

  37. Hello,
    I grew potatoes for first time this year. They were doing well, although they never grew more than a foot tall and didn’t flower. I visited my garden tonight for the first time in a week, and the plants were all dead. I dug them up and found that the potatoes are a decent size, and don’t appear to have any scabs or spots on them. I’m just wondering if there is any disease that might have killed the plants that would make the potatoes unsafe to eat? Thanks if you can take the time to answer. I’ve learned a lot by reading the responses to other peoples’ questions.

    • Some potato plant varieties do not flower. When the green, leafy tops of potatoes die back, it is a sign that the plant has run its course and that the tubers are ready for harvest–which you have already discovered. Leafy die back can also be caused by cool nighttime temperatures, but also by end of the summer heat and a lack of soil moisture. Your potato tubers are probably just fine and ready to eat.

      • Thank you so much for your reply. I was just going through this page again, planning for next year, and I realized I hadn’t acknowledged your answer. I do appreciate your taking the time to help me out and very generously sharing your knowledge with all of us.

    • If the potato tubers were exposed to sunlight, then the gold skin certainly could be sunburn. Look for greening below the skin and cut away the greening before cooking the potatoes.

      • I don’t think it is sunburn. I recently dug some up that had the gold all around them. If u scrub hard enough it come off. Could it be a scab or some kind?

        • Potato scab is usually corky or warty blotches on the tubers. Scab happens when the soil pH is greater than 5.5; adding aged compost will lower the soil pH. Other causes of tuber blemishes are feeding flea beetle larvae (rough spots and cracks), late blight which result in borwnish and purple spots, and fungal spores called black scurf.

  38. Hallo,, have been reading thru the whole page and am impressed with your help to others.
    Am afirst time potato farmer my plants are all green they have flowered for a bout 3 weeks now.. I gave them all the requirement but when i went to check on how they are doing i found many small tubers sizes of an egg what could be the problem cause now they are bout 95days. My question is will the new potato become bulky over time or?

    • If the soil is rich enough in nutrients and the green tops are getting plenty of sunlight as well as moisture, the tubers will grow to mature size. Hill up your potato tops with plenty of aged compost or commercial planting mix and keep the soil just moist. These ingredients will allow the tubers to mature.

    • The young tubers may have been too crowded. Next season plant your seed potatoes deeper and be sure to keep mounding the soil up around the green growth. New potatoes grow ABOVE the seed potato, so there must be plenty of room for new tubers to develop. Also be sure to give each plant plenty of room–at least two feet between each plant.

    • Start anew. Purchase certified disease-free seed potatoes from a garden center or nursery. Make sure you are getting seed potatoes. If the potatoes you have are not seed potatoes they may have been treated to avoid sprouting. Replant with seed potatoes in fresh soil. Make sure your pot is in full sun. Set the seed potatoes just an inch or two below the surface. As the green leaves grow, keep mounding up or adding soil so that all but the top few leaves are visible. You should expect a harvest in 80 to 120 days depending on variety.

  39. I bought seed potatoes and the tips of the sprouts/eyes are black on many of them? Am I still able to plant these and get a healthy crop or would this be a fungal issue of some sort?

    • The black tissue at the end of the potato sprouts is either dead or infected with fungal spores or bacteria. The safest course would be to purchase and plant certified disease-free seed potatoes.

  40. My potatoes have small black dots on the leaves. The dots go all the way through the leaves and appear on the bottom side also.

    • The black dots on the potato leaves may be a bacterial spot or bacterial speck. Bacterial infections are often brought on by wet conditions and war, temperatures. The leaves will exhibit dark brown water-soaked spots; later the spots become blackish and later affected tissue drops leaving a hole in the leaves; black raised specks may appear on the tubers. Control bacterial infections by keeping the garden free of weeds and plant debris; do not grow potatoes in beds that have had the disease; sow only disease-free seed potatoes. Mulch around plants to prevent infected soil from splashing onto foliage; remove infected foliage and dispose of it in the trash; when the entire plant wilts and is infected, remove it from the garden. Bacteria can overwinter in the garden so clean the garden of all plant material at the end of the season.

    • The “roots” of a potato are actually modified stems; tubers that grow from these stems or “roots” are a part of the plants stem connected to the green growth we see above ground. The stems grow from seed potatoes; they appear first as shoots that grow to the soil surface and then develop leaves. If you cut the roots (shoots or stems), the yield of the plant will be less. Seed potatoes can grow several shoots, so if some of the “roots” remain, new potatoes should grow.

  41. Hello,

    This is my first attempt at growing yukon gold potatoes in a garden bed.

    The plants look very healthy with lots of leaves but they are VERY tall. The seed potatoes were presprouted for 4 weeks before they were planted and at day 40 they are almost 4 feet tall!!

    Is this typical for yukon gold potatoes? I water them about once every 4 days (more or less depending on how much rain we’ve had).

    I am worried that there will be lots of top growth but no tuber formation.

    Thanks!

    • To ensure potato tuber formation, you want to regularly “hill up” the green growth; as the green growth develops mound up soil to cover all but the very top leaves. Keep this in mind for next season; it’s too late to hill up 4-foot tall plants now. Lots of green growth may indicate that the soil is very rich in nitrogen. Don’t feed potatoes a nitrogen-rich fertilizer.

  42. Hi, had a great crop of potatoes. Clean e shape and size. However, when cooked some of them have hard grainy bits in them? Any ideas if this is normal? My two teenage sons now refuse to eat them 🙁. (Other than the odd bits of stone? They taste and look fine)

    • Grainy bits, stones: if the rest of the potato interior looks good, cut out any bits that are not edible, you can then steam or fry the rest of the tuber. Stones or organic grit in the interior of the tuber may indicate that the planting bed or the tubers were disturbed during development.

  43. My potato plants were the first ones to come up this spring. Big, leafy plants that after a month were being eaten severely by a pest. Japanese beetles were seen and plucked off then plants sprayed with an organic insecticide. They have no blossoms, none. They are red potatoes and a golden potato. Bought as little spuds with rooting eyes. Could they be non-flowering? Plants are approximately 55 days old.

    • Potato plants flower at the end of their life. When a potato flowers, the tubers below ground are mature and ready for lifting–if they have not been lifted already. You can lift tubers as soon as they are big enough to eat–called new potatoes or baby potatoes; you don’t have to let tubers grow to full size. Check to see the number of days to maturity for the potatoes you are growing; harvest within a two week period or so of the days to maturity for full-size tubers; harvest earlier for new potatoes. Your potatoes will likely flower near the end of expected maturity.

  44. I found a rooted white potato so decided to see if it would grow, which it has and flowered so I decided to dig it up only to find that the white potato has produced about 12 dark pink / red potatoes. Are they safe to eat as it definitely was not a red potato that I planted?

        • Potato tubers are formed just below the soil surface. Tubers are stems, not roots. Shortly after planting time, begin mounding soil up around the green foliage; leave only three or four leaves visible. As the plant grows up sprouting new foliage, continue every week or so to mound up the soil so that only a few leaves are visible. Below-ground portions of the stems you have buried will form tubers. During the first 8 weeks of growth, feed your potato plant a high nitrogen fertilizer–10-5-5, for example (do this while the leaves are growing); after 8 weeks tubers will be growing underground so change the fertilizer to 5-10-10 (low nitrogen).

  45. I am getting couple of huge odd shaped potatoes. Is it ok to eat? I see it is because of heat stress, poor watering schedule which caused the tubers to get stressed and grow when moisture was made available. But now that i have them, i am wondering if it is ok to eat?

    • Slice into the potatoes; if the flesh is disease and pest free your potatoes are probably good to eat. Grow potatoes in loose, granular soil amended with aged compost or commercial organic planting mix. Add soil up to just below the top leaves of the plant giving the tubers plenty of room to grow unimpeded. Keep the soil just moist, avoid letting it dry out.

  46. Planted red potatoes and some harvested as dark purple are these still going to be edible the skin are dark purple and the inside is also dark purple we have a lot of oak trees in mi.

    • Is it possible some of the seed potatoes you planted were in fact heirloom purple potatoes? There are many purple potatoes–heirlooms include Purple Peruvian, All Blue, Congo, Vitilette, and Purple Majesty. It may be that the seed grower mixed some varieties together. If you slice the potato and you find no interior problems, it is likely the potatoes are good to eat. Purple potatoes are best suited for roasting, boiling, baking, braising, mashing, grilling, and frying. Oak leaves, like other leaves, will break down in the soil as a natural amendment; oak leaves are acidic but after the break down they are close to neutral on the pH scale; they should not affect your potatoes.

  47. Hi there, we planted some potatoes and they were growing well up until about a week ago when we put some more soil on top. The potatoes have failed to sprout and all the green bits are gone, leaving small amounts of stem in the soil. Any idea what could have happened?

    • When you hill up potatoes, bury the stem to the lower leaves; do not bury the entire stem. Use light soil to hill up. If you have clay soil, you may want to use straw instead of soil. Perhaps your soil was too wet when you hilled up. Leave the stems exposed–or if there are any buried leaves give them sunlight. If the exposed stems look viable, not rotted, give them a week or so to see if they will regrow leaves.

  48. FIRST TIME POTATO GROWER IN A RAISED BED. PLANTS GREW WELL AND 1 WEEK AFTER THE FIRST FLOWERS ADDITIONAL LEAF GROWTH STARTED TO APPEAR AND LOOKS VERY HEALTHY. i FEEL I NEED TO HARVEST ANYWAY. ANY SUGGESTIONS AS TO WHY THE NEW GROWTH?

    • New growth simply suggests the plant is not yet ready to die. Vegerables often decline after flowering, but not always. You can dig down and harvest potatoes at any time.

    • The problem may be bacterial ring rot; pull and destroy the infected plants. Disinfect your hands and tools before handling healthy plants. be sure to remove any crop debris from the garden.

  49. I put copper sulphate on my potatoes upon the recommendation of a fellow allotment owner. The foliage has wilted and leaves are no longer healthy and green. Will my potatoes recover? Or have I lost the crop?

    • It’s best to experiment with a few plants rather than the entire crop when trying a new fertilizer or amendment; that way you can hedge your bet. The plants may recover in time; continue to water as usual keeping the soil just moist; do not add any other fertilizers or amendments this season. Start some new plants in a different planting area.

  50. I am a new gardener. I started a veggie garden this year and one of my plants are potatoes. I purchased 2 different kind of seed potatoes from country max 3 of each and planted all six about 4-5 weeks ago. After some time I started getting the stalks or tubers coming up from the potatoes they have been growing great getting tall. This morning I went out and checked on the garden and everything was fine I went and did some yard work. Came back a couple hours latter and half of my stalks were laying sideways. Now their not broken, yellow, spotted, wilted etc. They look perfectly fine just laying down. So I hilled them up with more soil and put braces around the outer edge so if they fall again the brace will keep them from laying flat. Any idea on why this is happening? I know they are not ready to be picked yet because I didn’t see any flowering and it’s only been like I said 4-5 weeks. Thank you.

    • Could the plants have been walked on by an animal? If not, very sudden wilting could be caused by a lack of soil moisture or an over-application of fertilizer–or other chemicals. Trim back the damaged plants; remove broken plants; be sure the soil stays moist.

  51. I am brand new to potatoe planting and planted about 30 days ago. Now I have the part that sticks out of the ground, near the soil level, get yellowish and shriveled and then it consumes the whole green part and dies off. Not all of my green plants have done this but I good majority. I have read in detail your entire post but I am unsure what is wrong with them. The green shoot grew very quickly and I kept adding soil and mounding it. This is a container garden so to speak. The container is a 4 feet or so high Christmas wrapping paper holder. My plants have organic soil with aged mulch and plant food. The plants haven’t gotten to “flower” I don’t think as I assume there should be a flower. I do have leaves. Please help!

    • Make sure the container is well-drained, that water is not collecting around the roots. As well, be sure the soil is just moist. Yellow and shriveled leaves can be a sign of too much or too little water, temperatures too low or too high, or too much nitrogen or fertilizer in the soil. Let the plant gain strength and grow to 12 inches tall and wide before hilling up the soil. If the plants fail, plant again with the above tips in mind.

  52. Hi,
    My king Edward potatoes have grown to 4 feet tall and been blown over with heavy rain and winds, I know the high growth is due to too much nitrogen as i put potato fertiliser in the troughs at planting and the soil is very fertile due to keeping free ranging chickens in that area for 5 years and everything grows great, I thought I was giving my spuds an extra starting treat sigh, but i have had to cut the top 12-18 inch from the tops of each plant to get them to support themselves off of the ground, I have always taken the flower heads off to encourage tuber growth but my question is will the plants be susceptible to disease where cut and will the tubers develop more now or will the plants keep growing due to the high nitrogen.
    Regards John.

    • The high nitrogen is supporting foliage growth but it is likely tuber growth will suffer. The plants are unlikely to suffer disease as a result of pruning–that is always a possibility, but your plants are healthy. If heavy rain is in the forecast you can place a frame at the corner of the planting bed and drape clear plastic sheeting over the top; this will protect the plants from pounding rain.

  53. I had 6 plants growing beautifully until flowering. Deer ate the top foot off all my plants and since then, the top sets of leaves are cupped. Not sure if it’s the damage from being eaten, overwatering or some pest. Anyone know? See website link for photo.

    • The curling leaves in the photo are likely the result of hot temperatures or uneven watering; keep the soil moist, not wet or dry.

  54. I don’t have enough room to hill up the potatoes much, there are no potatoes visible but the leaves above the mound are about 3-4 foot tall. Are the potatoes going to be inedible?

    • Hilling will increase the number of potatoes below ground; you may still have tubers to harvest–however, lots of green growth will take nutrients away from tuber development. If it is possible, you can hill up around the plant with straw rather than soil.

  55. I wish I could just upload a picture here! The potatoe plants are going yellowish and looking less vital, with little deep red stuff on the base of so,e of the leaves.
    They also don’t seem to be growing much, depsite lots of sun and lots of rain over the last 3-4 weeks (I have wterred thej if no rain for 3 days).
    They were plamted in the early-mid summer (I knos that’s late – but online it said it shoud be fine and the crop shouod be ready in October

    • The red may be the start of mold growing as a result of very wet weather. Yellowish leaves may be an indication the tubers below ground have reached maturity and are ready for harvest; the plant will naturally die back when the tubers mature. Remove some soil and check to see if the tubers are ready to be lifted; do this before the plant is infected with mold.

  56. I grew potatoes last year in 5-7 gallon fabric pot containers, with nice results all around. No disease problems at all. However, I started harvesting my potatoes this season and today I found one container of Yukon Gold seems to have developed scab. Irregular shaped potatoes, hard warty protrusions, dark discolorations, yuck. Only 1 potato looks okay.

    I was just going to throw them away, but decided to stick them in the basement and read about scab. This site is very helpful!

    I have a couple of questions:

    1) Should I wash the potatoes off before I let them “cure” in my basement? I didn’t last year, but with these, if the bacteria is in the soil on them, should I get it off them ASAP?

    2) I understand that these are edible if I cut the scab off. Does it invade the interior of the potatoes at all, and if so, would I see obvious discoloration so I can remove it?

    3) If I want to grow other plants in this container/soil, are there veggies that will not be affected by the scab bacteria? You indicate some root vegetables (beets, radishes, turnips, carrots) would not do well – how about tomatoes, peppers, eggplants, cabbage, brussels sprouts, broccoli, cauliflower?

    How to get rid of scab – There was mention of ammonium sulfate as an additive to deal with scab – will it “treat” soil that has scab? If so, how much would I mix in to a 5-7 gallon container? or how much elemental sulfur, if that’s better? or dumping in a gallon of 1:10 bleach solution?

    I’m guessing this came in on a seed potato, although I used a couple of very good sources. I don’t want to see that on any more of my lovely potatoes!

    Thank you for any help,
    Linda

    • Washing potatoes ahead of storing will decrease the amount of time they will keep. Scab affects the skin of the potato; if any of the flesh of the potato is corky, cut it away before preparing. Fungal spores can remain the soil. Since you are growing in containers, the best course would be to use fresh soil for the next crops. When growing potatoes maintain a soil pH of 5.3 or less. Grow scab-resistant potatoes such as Cayuga, Cherokee, Norgold Russet, Norland, Seneca, and Superior.

      • Thank you! I haven’t washed them, so that’s good based on your response. They really look a mess, though. I guess I’ll ditch the soil and start over, and hope none of my other spuds have this problem.

  57. how do you control the height of the potato plants. ours continue growing and are already 24 or more inches high after only 4 weeks planted.

    Liz

    • You can control the height of a plant by nipping out the tip or growth bud at the end of a stem. You will see tiny new leaves forming; simply nip them with a thumb and finger or a garden scissor.

  58. This is an awesome and informative website. Thank you for taking the time to answer all of the questions. I bought too many seed potatoes this year. I live in Asheville, NC and am wondering if I should try for a second crop? I will soon have an open spot where I planted garlic that is just about ready to be pulled up. Thanks again for sharing your knowledge!

    • Seed potatoes usually need about 10 weeks to produce good-size tubers; if you plant now, you should get a second crop before frost kills the leafy tops.

  59. Hello Steve ; Some of my potato plants are flowering . I have removed the flowers . Why are they flowering ? This hasn’t happened in the past and I’m unsure if the potatoes will still be good ?

    • Potatoes generally flower about 50 to 60 days after seed potatoes are planted. Check the tubers to see if they are near harvest size. The potato tubers will be good even if the plant flowers.

        • Removing the flowers will not increase the yield. When potato flowers appear, potato leaves will be at their full size and able to produce the energy and food tubers need to grow larger. When flowers appear, you can dig down into the soil to see how large the tubers are. They may be small and tender–called new potatoes–or they may be larger. You can harvest the tubers at the size you want–large or small.

  60. My first time growing potatoes in raised beds. The plants have been beautiful but russet potatoes are dry and bitter. Red potatoes are very good. I planted the eyes about 6 inches deep, covering with a small amount of soil. As they appeared, I added more soil. I have watered faithfully.

    • Different varieties will react differently to dry weather and dry soil. Generally, potatoes that are dry and bitter went too long without water at some time during their maturation. Be sure to water during hot and dry weather; keep the soil just moist throughout the plants’ growth.

  61. Do not eat this crop. It sounds as though the soil was too wet. If you are growing potatoes in a container, you should be very careful not to overwater and to protect the soil from soaking up rainwater. Plant potatoes in a wire basket filled with straw (they will grow), or in a wooden container–moisture in a wooden container will evaporate more quickly than in a ceramic or plastic pot.

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