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Sweet Potato Growing Problems: Troubleshooting

sweet potato problems solved
Sweet potatoes prefer regular, even watering until they are established. Keep planting beds weed free

Sweet potatoes require loose, well-drained soil and about 100 very warm days.

Sweet potatoes are usually grown from slips started from roots (to start your own add another 40 days).

Set sweet potato starts into the garden about the same time you set out tomato transplants in spring.

For sweet potato growing tips see Sweet Potato Growing Success Tips at the bottom of this post.

Common sweet potato growing problems with cures and controls:

• Transplanted slips or sprouts die or do not produce vines. Sweet potato transplants (slips) must be kept evenly moist until they root. Transplant out slips that are good sized, not slips that are thin or frail. Set transplants in the ground up to their top leaves; bury the remaining nodes so that they will root.

• Leaves become yellow or brownish, wilt and droop, brown to black steaks inside stems; plant become stunted. Fusarium wilt is a fungal disease which infects plant vascular tissues. Fungal spores live in the soil and can be carried by cucumber beetles. Plant disease-resistant varieties. Rotate crops. Remove and destroy infected plants. Fungicides are not effective.

• Water-soaked blotches on leaves–not enlarging past leaf veins. Leaf spot or bacterial spot is a waterborne bacterium which causes irregular geometric patterns on leaves. Spots may turn yellow and crisp. Avoid wetting foliage with irrigation. Prune off infected leaves and stems. Clean up garden. Plant disease-resistant varieties. Rotate crops up to 2 years.

• Small shot-holes in leaves of seedlings. 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 roots of germinating plants. Spread diatomaceous earth around seedling. Cultivate often to disrupt life cycle. Keep garden clean.

• Holes in leaves and roots. Larva of sweet potato weevil is a white, legless grub with a pale brown head about 3/8 inches long; the adult beetle has a reddish snout. The grub will tunnel through leaves and roots. Pick off weevils. Remove and destroy infested plants. Sprinkle plants with diatomaceous earth. Cultivate the planting bed before planting to disturb the weevil’s life cycle.

• Leaves turn yellow and then brown from the bottom up; plant loses vigor; cracks in roots. Root knot nematode is a microscopic eelworm that attacks roots. Plant resistant varieties. Rotate crops. Remove old plant debris from garden. Root cracks also can be the result of too sudden uptake of water; keep watering even; avoid dry and wet spells.

• Roots are elongated, slender. Too frequent watering. Sweet potatoes require consistent, even moisture, but roots should not be constantly moist. Water deeply for 2 to 3 hours at a time then allow the soil to dry to a depth of 6 to 8 inches before watering again. Heavy, clay soil which retains moisture can cause sweet potato roots to become long and stringy. Add aged compost to planting beds to increase drainage.

• Root flesh is stringy. Soil is too wet. Roots should not be kept constantly moist. Avoid overwatering; make sure soil is well drained. Water deeply for 2 to 3 hours at a time then allow the soil to dry to a depth of 6 to 8 inches before watering again. Heavy, clay soil which retains moisture can cause sweet potato roots to become long and stringy. Add aged compost to planting beds to increase drainage. Reduce watering a few weeks before harvest.

• Tunnels or hole in tubers. (1) Wireworms or (2) sweet potato weevil: (1) 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. Remove infested plants and surrounding soil. (2) Sweet potato weevil is a blue-black weevil that resembles a black ant; the larva is a white, worm-like grub that will feed on plant stems and roots. . Weevils lay eggs in the soil and the worm-like larvae will eat stems and roots. Mound up soil around plants so that weevils can not reach roots. Dust plants with a small amount of diatomaceous earth.

• Round to black spots and blotches on root surface. Black scurf is a fungal disease that favors warm soil. Remove infected plants and plant debris that harbor fungal spores. Rotate crops. Be sure slips are not diseased. Plant certified disease-free slips. Rotate crops regularly. Solarize the soil in late spring or summer. Black scurf is resting spores; peel away the surface spores before using the root.

• Black sunken spots on roots and underground stems; leaves are yellow. Black rot is a fungal disease. Roots will have circular black decayed areas that become dry and corky. Use only certified healthy slip and resistant varieties. Keep garden free of weeds; some diseases are spread by insects such as the sweet potato weevil. Avoid bruising tubers at harvest.

• Internal cork, hard corky spots in root. Internal cork is a viral disease transmitted in the propagation, using diseased stock and also by aphids. Leaves will become mottled and yellowish along veins. Plant certified virus-free slips. Control aphids. Do not save roots from infected crops for planting next year.

• Sweet potatoes have poor flavor. Harvest roots before soil temperatures drop below 55°F. Harvest should be completed before the first frost.

• Roots rot after harvest. Bacterial rots can enter roots through harvest wounds; sweet potatoes are very thin skinned. Cure just harvested roots for about a week at 75°F. Store cured sweet potatoes wrapped in newspapers at about 55°F.

• Parts of roots are hard after cooking. Sweet potatoes should be stored at about 55°F, not cooler. The tissue of roots stored too cold will become dry and hard.

Sweet Potato Growing Success Tips:

Planting. Grow sweet potatoes in full sun. Work 2 to 4 inches of aged compost into the planting beds before planting. Plant rooted slips for best results. You can start your own slips from sweet potatoes grown the year before. Allow 40 days for sweet potatoes to root. Use a large, firm sweet potato; place the potato in a pot of moist sand leaving two-thirds of the root exposed. Put the root in a sunny place at about 75°F. When sprouts are 4 to 6 inches long, twist them from the potato and put them in water or wet sand to root. Transplant the slips into the garden when the roots are about 2 inches long.

Planting time. Plant sweet potato slips after the soil has warmed in spring to at least 65°F or warmer; soil temperature of 80°F is ideal. In cool regions, grow dwarf or early-maturing varieties and plant them in raised mounds or raised beds where the soil warm quickest and stays warm.

Care. Sweet potatoes prefer regular, even watering until they are established. Keep planting beds weed free.

Harvest. Begin lifting sweet potatoes when they have reached the number of days required for maturity–check the seed packet or a growing guide. Keeping track of average days to harvest is the best way to know when to harvest sweet potatoes. An unharvested sweet potato will continue to grow and grow, but it is best harvested young. Sweet potato tubers are easily injured so lift them gently after loosening the soil with a spading fork. Cure sweet potatoes for 10 days in a dry, shady place before using.

More tips: How to Grow Sweet Potatoes

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95 Comments

  1. I have raised sweet potatoes for over 10 years, this is the first time I have ever seen sweet potatoes like what I dug up this year. The first 2 or 3 inches on the top looks good but then the rest of the potatoe is very rough and flakey. I don’t think will keep through the winter. Do you have any ideas of what caused this? If you do please reply. Alberta, Thank you.

  2. Rough and flaky sweet potatoes: this might be the result of wet weather, over-watering, poor soil drainage, or the variety of sweet potato you are growing. Next season grow a different variety, be sure to add lots of aged-compost to the planting bed in the off season (to insure the bed is well drained), and cut back on watering for the last two or three weeks before harvest. Planting in a raised planting ridge through a plastic mulch or sheet may help where the weather is on the wet side.

    • Cracking may be a sign that the tubers have had a period of rapid growth–usually due to an increase in soil moisture (this can happen if the soil has been dry and then a heavy rain comes). To prevent cracking keep the soil evenly moist by mulching the planting bed. You can also use a soil moisture monitor to watch for soil moisture waning.

      • I’ve picked my sweet potatoes/ camote for the first time and was so surprised to see a very huge one, about 2-3 lbs big. Is it still safe to eat it?

        • The larger a sweet potato grows the more fibrous and sometimes woody it may become and, as well, less edible they may become. Try the one you have just harvested, but in the future harvest earlier.

  3. Thank you so much for this article.. I am so excited to have some help. I am a super beginner and very excited with my new Sweet Potato plant.. I live in the Republic of Panama so it is HOT and Humid here in a big way. So far they look good I think.. But Grasshoppers have eaten a few leaves.. Also I do have 2 yellow leaves one with a Black tip.. Does this mean I have eelworm? Do I need to take up the whole plant of just the yellow leave? Thank you so much for your help..

  4. We grew sweet potatoes a couple of years ago and the tubers grew very large but several tubers would curl around each other forming huge clumps. We planted again this year and we have dug a few around the edge and I’m noticing the same thing happening. Not all of them curl around each other though so I’m confused as to what is happening. Our soil is mostly compost and leaves from 20 years of adding in. I have searched the internet but can’t seem to find an answer.

    • If the tubers show no sign of disease, then the curling of the sweet potato tubers is likely environmental. Environmental causes could be a stone or pebble in the planting bed that the developing tuber simply runs up against the make a turn to avoid. Other environmental stresses would include too little or too much water, too much fertilizer, a planting bed too densely planted.

  5. We grew some sweet potatoes as a trial but at least 50% of our harvest were potatoes that were too big (2kg+), any idea why that may be the case ? Otherwise looks like a healthy harvest

    • The differing sizes may be attributable to difference in soil in the growing bed–water and nutrient retention–if all of the plants got their start in the garden at the same time and assuming all are the same variety. Well-drained sandy loam is the best soil for sweet potatoes. Sweet potato tubers do not stop growing when they are ready for harvest; were the tubers harvested earlier smaller and those later larger? That would be expected.

  6. I harvested one of my four sweet potato plants today and found a few sweet potato weevil larvae in the soil. Fortunately no tubers had been attacked but there were only 2 small sweet potatoes because the plants are only about 90 days old. My other 3 plants are 2-3 feet away. Do you recommend harvesting them early as well before they get infested, or letting them get closer to maturity? I sprayed them with neem oil and dusted them with DE earlier today.

    • Harvest the sweet potatoes as soon as they are big enough to eat. You can treat the soil with beneficial nematodes–you can get the at a nearby garden center. The nematodes will attack the weevil larvae in the soil; neem will kill the larvae if you spray them directly.

  7. I’m curious if you have ever had the experience of tubers sprouting underground? I’m guessing the variety I planted must have been a shorter season crop because each and every tuber started to sprout and grow under the soil, just like when you’re starting slips.

  8. Thanks for a great article. This year is the first time I’ve harvested sweet potatoes and found bug damage on the tubers. Is there any way to save the lesser infected ones? I’d hate to lose the whole crop. I usually put them in vented boxes and cure in a small room with a heater for 10 days. With this I have been able to keep them for a year.

    • Insect or environmental damage to sweet potatoes tubers will likely mean they will not store as long as you hope. If the wound heals during the curing process, the tuber may keep. Keep an eye on the damaged tubers and as soon as you suspect they are not keeping, use them.

    • If you are growing a sweet potato purchased at a grocery store it was likely chemically treated to prevent sprouting. Grow slips from certified organic sweet potatoes which are not treated. Make sure you place the slip where it gets plenty of sunlight all day.

  9. Hello. Just dug our sweet potatoes. So many have a dark color instead of the normal orange color. Lots of dark spots. We have been taking them and thy taste great! I have two sweet potato pies in the oven right now. Any thoughts on the discolored ones? Thank you!!!

    • The discoloring of the sweet potato skin is likely a fungal disease called black rot or a similar fungal disease called soft rot (Fusarium). Tubers can be eaten right after harvest by cutting away the discoloring;; however, if you plant to store the tubers they should be cured at about 90F and treated with a fungicide. Black rot does not affect other crops apart from sweet potatoes and potatoes, so it is safe to plant other crops in the same bed next year. But you should rotate tuber crops to another location next couple of season. Clean the bed of any plant debris.

  10. So, I bought a sweet potato in the fall 2017 with the intention to eat it. It found its way into the pantry and was forgotten about and when I came across it I noticed it had started to grow some sprouts. I plant potatoes but have never planted sweet potatoes so it led me to research planting sweet potatoes. While there is so much varying degrees of opinions with regards to starting sprouts I wasnt sure what to do but decided the toothpick method in a jar of water. It’s should be noted that this is a particularly large sweet potato about 10in in length and has a girth larger then a wine bottle. The first few weeks I noticed some minimal growth from approximately 1in to 3in and it appeared to be healthy. The next few weeks it had produced nothing. It seems to have stalled and I’m not sure why. I have kept it on a window sill that receives 3-4 hours of sunlight a day. I live in a winter climate and the window sill gets cold at night but not too cold. I thought this could be a problem so I moved it. It has also produced a root at the bottom of the tuber but that seems to have stalled as well. There also were some small soft/rotten spots below the waterline that I cut out. Being my first attempt I wasn’t expecting it to turn out but if anyone has any information that could help that would be awesome. Thanks

    • Warmth and light are essential for rooting sweet potatoes from tubers or cut pieces of tubers. Keeping the starter under a grow lamp will give the start both the light and warmth it requires. Sweet potatoes do not like chill. You can also change the water in the contaner daily.

  11. My sweet potatoes sprouted in the ground the same season. They are all long and then We had a lot of rain. Are they okay? I have had a great crop of sweet potatoes every year for 10 years.

    • Try a few to see if they are tasty. On the off season, add lots of aged compost or commercial organic planting mix to the planting beds to make sure the bed is rich in nutrients and well drained. You should do this every year to ensure the soil remains nutrient rich. It may be that the soil is tired and not well drained.

  12. Hello, the soil is very rich. It is the nicest 100 year old farm soil, deep, light and plenty of cow manure every year. They are weeded. I have grown sweet potatoes for 10 years and get giant fruits. This year is different. There were lots of green growth. But some plants don’t even have bulbs under them. Than you for your suggestion.

    • Green top growth without tuber formation; add bone meal to the planting holes next spring to increase phosphorus–important for tuber formation.

  13. First year growing sweet potatoes. I just dug around and found some of the sweet potatoes and they were still a little small so I covered them back up but 4 fell off the roots so I brought them in from the garden. How big should a tuber be when I harvest it? These are small then what I usually see in the grocery store. We are still having 60 degree whether here but I think it’s supposed to drop to 50s at night. Should I harvest them now? Also do I just pull the entire plant up and let it sit like that to “cure”? Thanks!! I’m excited to try them!

    • You can eat a sweet potato at any size; small is okay. To know the optimal time to harvest a sweet potato, you should know the variety name and the number of days to maturity for that variety (most sweet potatoes reach maturity in about 100 days from planting). Harvest at the number of days to maturity. Sweet potatoes will continue to grow and tubers will continue and enlarge (to more than a foot long) as long as the soil and air are warm enough (about 65F or warmer). Sweet potatoes stop growing when the temperatures drop below 60F. When temps drop into the 50s foliage and tubers can suffer injury–so go ahead and harvest.

  14. I planted Ol’ Bunch Porto RICO’s about 160 days ago. But they are small… the size of baby bakers (maybe about 1/4 lb). I would like them to get to 3/4 lb to 1 lb. It’s getting cooler… I may have 2 weeks to 1 month left to chance leaving them In the ground. Is there a reason why they are still so small? I’m growing in Northern Mississippi. Should I just pick ‘em or can I try for a bit bigger?

    • You can leaves sweet potatoes in the ground until the leaves begin to wither or turn brown. Harvest them right away once leaves begin to turn from green with yellow or brown.

  15. I am from San Diego, I got inspired to plant sweet potatoes when one of our sweet potato 10″ began to grow vines. I did my research on how to harvest slips from the mother sweet potato. I was able to get approx 20 slips and I was able to get each one to root for about 2-3 weeks. I chose to plant them in a large 20 gallon container and I spaced them about 3-4 inches apart. I took the mother sweet potato and for fun placed it about 2/3 of the way into the soil in the middle of the pot. Each slip grew and vined everywhere from Aug 2018 -Dec 2018. I gave the soil a good soaking and then I watered the container once a week. The weather between Aug – Nov ranged from 75-100. We had hot weather this year. I decided I would give the plants some extra time to grow and thinking that the tubes would get bigger. The vines even went though the blossoming process in the month of November. Beautiful light purple with a dark shade in the middle. Well today Dec 3 I decided to harvest them. I only found 5 tubes and they were the size of my finger and about 3-4″ in length. the soil was moist not wet and I had vines that were anywhere up to 8-10 ft in length. I have no idea what went wrong. I did take good healthy vines that had new growth on them and cut them in 10-12″ pieces and I put them in water to see if I can get them to sprout new roots. Any suggestions or recommendations to trying this all over again. Thanks any tips will be a blessing.

    • If I understand correctly, you planted all 20 sweet potato slips in one 20 gallon container. In the end, the plants produced very small tubers. Next time around, plant one slip or rooted plant in its own 10-gallon or larger containers. That is one plant per each large container. This should allow each plant ample room to produce larger tubers.

  16. Hi I m from Singapore with an average 32 degrees celcius everyday.
    My sweet potatoes vines grow wild after 1 month planted in planting bag.
    As the weather here is hot and humid, can I water them everyday?
    Also, does pruning the sweet potatoes vines affect the size of tubers?
    Or I should just let the vines grow without pruning them?
    Appreciate your help very much.

  17. Hi,
    I live in Los Angeles zone 10b. I planted 3 organic supermarket sprouted sweet potato tubers in pots in Late July with the thought that I could separate the slips later. The ground was really heavy clay and needed a lot of work, which needed a lot of compost and other amendments(bone meal, sand, peat moss, etc.). It took a lot longer than I anticipated. By the time the ground was fluffed up and conditioned into raised mounds, the roots in the pots filled to almost being completely root-bound in Mid-August. I was afraid to separate the slips for fear of damaging them, so I just planted the entire tubers in the ground.
    They’re growing like crazy, but green caterpillars are eating the leaves, so I sprayed them with Spinosad.
    Since this my first time planting sweet potatoes, I figure that I will be lucky if I get any good harvest. If anything, at least I could plant other things later.
    Do you think I’ll get anything from this haphazard approach?

    • Your sweet potatoes will likely produce new tubers alongside the mother tuber. The slips or sprouts growing from the mature tuber will produce their own roots. It is best to separate slips from the mother tuber and set the slips at 12 inch intervals. You still may be able to gently dig down around the mother plant and separate slips and replant them.

  18. My sweet potato patch is in SW Mo near Springfield Mo.
    I try to plant in late March but this year the slips didn’t arrive till mid April. They “sulked” for about 30 days then took off turning into a ankle deep jungle 30 feet wide by September.
    I need to figure a way to grow a lot of 1 pound tubers rather than 3 or four ginormus tubers and a few baking size under each hill.
    I just dug a hill of O Henrys that totaled 25 pounds with 20 lbs. from 5 tubers.
    Soil is loamy but thin with good internal drainage and small rocks. Other garden crops do well with the usual problems present with gardening the same area yearly.

    • Spacing sweet potato plants is important in order to grow tubers that are consistent in size. Create a furrow 12 inches wide and 1 to 2 inches deep; fill the furrow with aged compost or manure. Create a ridge over the furrow that is 12 inches wide and 10 inches high. Set plants 4 inches deep and 15 inches apart along the ridge; space ridges 3 to 4 feet apart. (You can also plant on hills using the same method; space hills 15 inches apart.) Plant when the soil is at least 65F. Tubers take about 5 months to mature; they double in size during the last month. You can dig tubers at any size large enough to use (called “baby bakers”). Harvest the main crop at the time of the first fall frost.

  19. I planted purchased slips into 8 cloth bag planters for growing this year in zone 6. The two varieties are Murasaki and Bush Porto Rico. When I harvested them, over the past week, I noticed two big things. Several of the ones that actually grew in the pots were smallish and a lot of the skins had turned really dark. However, there was a rebellion of sorts — with (1) several pots having roots that penetrated the bottom of the bag, winding their way into cracks and soil underneath the stepping stones they were sitting on and (2) the foliage finding places to take root in the soil and create a potato in a place that I had not actually planned. The renegade potatoes (even though extremely hard to harvest and shaped like all-kinds-of-crazy) were more normal looking in the skin color and a bigger volume. I am thinking that the cloth pots allow the tubers to dry out too much. What options do I have if we use mostly raised beds and containers for our vegetable gardening?

    • If you suspect the soil dried out or perhaps went wet then dry then wet with irrigation, here are three options you might try next season: (1) use larger grow bags that hold more soil; a greater amount of soil will be slower to dry; (2) place the grow bags in a larger plastic or clay pot; this will slow moisture evaporation through the sides of the cloth bags; you can cut the bottom off a larger plastic pot allowing greater drainage than if you planted in a pot with a bottom; (3) plant in a raised bed.

  20. I live in the Boston suburbs and planted my purchased sweet potato slips approx 5/20/19. Just dug them up. They were planted in raised bed gardens and grow bags.

    All of the sweet potatoes were rather small and elongated. Didn’t fertile during the summer.

    Any suggestions for next year.

    • Sweet potatoes that turn out long or stringy have commonly been planted in soil that is too heavy or space for tuber growth was constricted. Chances are you planted the tubers in grow bags in a potting mix–if not do that next season; it will be lighter. In the raised beds, a sandy loam is ideal–add some sand to the organic materials when you rejuvenate the beds for next season. Give sweet potatoes a deep bed, at least 18 inches, and make sure the soil is well-drained. Too much nitrogen will stunt tuber growth; use an organic 5-10-10 fertilizer. Overcast weather can slow growth; keep your planting beds in full sun as much as possible. Finally, plant a bush variety of sweet potatoes such as ‘Porto Rico’. Burpee, Park, and Gurney seed companies usually carry bush sweet potato seeds.

  21. I am in Houston TX and have a question.

    I had tremendous vines all summer, but when harvesting the plants, there are no tubers. The plants were healthy all the way up to a mid-October cold snap killing the leaves but not the vines. I left them for about a week to see if the would start leafing out again, but no. So, I harvested. On 20+ starts, I got less than 5lbs of sweet potatoes.

    I know root crops need cooler weather to form – is it then just too warm here for sweet potatoes. I use compost, decomposed wood chips etc. I’ve always thought sweet potatoes were supposed to be an easy crop here – and if wanting leaves, yes they are, but I want the root tubers.

    Sweet potatoes tie up the soil for a long time and are somewhat of a nuisance in an urban garden due to the vine lengths.

    If they’re not going to produce, I’m going to need to move on to more productive crops. This is the 2nd year I’ve had a very dismal harvest.

    Any thoughts would be appreciated.

    • Sweet potatoes produce best in a well-drained, light, sandy loam or silt loam soil. Rich, clay soils and soil too sandy will produce low yields of roots. Poor surface drainage resulting in wet spots will reduce yields. Poor internal drainage will also reduce yields. Use a 5-10-10 fertilizer; work some fertilizer into the soil before planting and then fertilizer one more time when leafy growth has begun. Too much nitrogen will reduce tuber growth and yield. A loamy compost is good but decomposed wood chips Reduce the use of decomposed wood chips which may contain residues or may alter the NPK of your fertilizer.

  22. Hi, Steve. I planted exactly one organic sweet potato in a large, deep garbage can in a sunny spot in my apartment. I do not have any outside area to plant, but my plants all seem to do well in the sunny end of my house. I planted the sweet potato sometime between the end of May and the first week of June. It grew the most beautiful vines and big green healthy leaves that overflowed the pot and wandered all over around the floor. Finally, the leaves started turning old and dropping off in early December, probably because the cold hit, so I decided to harvest the sweet potatoes. However, there are NONE at all. Not even a tiny one. The mother potato appears to have grown longer under the soil, but that is it. I sifted all the soil and found nothing. If the plant seemed to thrive, what am I doing wrong? Oh. It never flowered, either. I was so psyched to see it growing, but now I am discouraged.

    • The likely reason your sweet potato plant did not flower or form tubers AND the foliage was spectacular is too much nitrogen in the soil. Next season, check the NPK (nitrogen-phosphorus-potassium) on the label of the potting soil you use. A low NPK of 3-3-3 or 5-5-5 would be best. When you feed the plants use a low or no nitrogen fertilizer such as 0-5-5 or 5-10-10. Increased phosphorus will aid flowering and fruit set and development. Nitrogen encourages lush green growth.

  23. We threw some sweet potatoes in the garden and they had amazing foliage which after having flowers were eaten by the chickens, the stems are intact . will I have tubers ?

  24. I live in San Antonio, Texas and I planted some sweet potatoes a few months ago. The leaves are pretty but beginning to change from a bright green to a brown, but they are healthy looking. Should I harvest those plants that are turning. Also, I found these orange pebble looking things in my garden with the sweet potatoes. I figured they were some sort of fungi but wondered if that would hurt my sweet potatoes. Should I did that out? They look a little bigger than a bebe but there are a bunch of them and they are bright orange.

    • If the leaves are turning brown and dying, the plant is signaling the end of its life; the roots will be ready for harvest. Sweet potatoes can be harvested at any time they are large enough to eat. If you find the roots are infected with the fungi, then do not eat them.

    • Be sure the sweet potato is getting plenty of light. When sprouts (“slips”) form, remove them and root them in sand or a light potting mix. The tuber and in turn the leaves may be taking up more moisture than needed. Root slips as soon as possible to separate them from the tuber; the roots will take up nutrients that may allow new leaves to form, replacing the leaves that are failing.

  25. Something snipped the leaves off of my newly planted slips. Maybe birds? I don’t know. The leaves were left in the pot, not eaten.

    But I need to know if the slips will continue to grow, or do I need to get more slips and replant? I am in the Pacific Northwest, and an growing the sweet potatoes in latge containers

  26. I am a first-time sweet potato gardener, and my husband loves sweet potatoes. We planted slips in some parts of our garden and tried planting sectioned potatoes in other parts, just to see the differences and try to learn the most from our growing season. We have very sandy, loose soil that we amended before planting. The slips look great! They are growing heartily after an initial set-back. The potato sectioned plants have been doing great, as well, until now. One “mound” has leaves that have all yellowed with some showing browning in edges. The stems at the base of the plants are still green. They get plenty of water and have been fed with nitrogen and other nutrients. I read somewhere that magnesium deficiencies could cause issues. Does my problem sound like a magnesium issue?

    • Burnt or browning leaf edges can be caused by inadequate or erratic soil moisture; keep the soil evenly moist. The young plants could also suffer a burn if too much nitrogen was added to the soil. Be very careful feeding young plants; they need several weeks to establish themselves; then feeding can begin. A symptom of magnesium deficiency is interveinal chlorosis or yellowing between leaf veins; the veins stay green by the leaf tissue in between which has a yellow-marbled appearance.

  27. I have some organic sweet potatoes I
    been soaking elevated in 1/2 water with
    toothpicks for about 3 months. They are only sprouting roots and green vines from the submerged end. The top skinner end outside of water remains bear. I have googled which end to put in water and have found conflicting reports as to which end is correct. These sweet potatoes have the pointy end out of the water.
    Can I plant the entire sweet potato in soil laying on its
    on its side? Not sure what to do?

    • Lift the sweet potato from the water; you can set it in moist sand or vermiculite or a seed starting mix; make sure the roots are covered and the sprouts are above the media. In a few days to a week, you should be able to separate the sprouts from the mother tuber; you cut the tuber so that sprouts and roots are intact for each piece. Plant those pieces in potting mix; leaves should develop in a week or two.

  28. I planted about a dozen sweet potato plants that were all doing very well until this week. the leaves are all turning a dark olive green and a few are starting to get brown spots on them. It has been unusually cold in the evenings here, down to about 37 degrees F. I’m wondering if this could cause the discoloration? or am I dealing with a disease? the bottom of the plants and smaller leaves underneath are still bright green and look healthy. The plants are all spread out about 3 feet apart from each other, in a row that’s about 40′ feet long. Every single plant looks exactly the same. Thanks for the insight!

    • Cold is likely the culprit. Place hoops over the planting bed and cover the hoops with clear plastic sheeting; this will protect the plants from cold; lift the sheeting during the day so that temps inside the tunnel do not get too hot. If you can’t do a tunnel; cover them with floating row covers.

  29. Hi! I ordered sweet potato bare roots from Burpee website and placed them in a cup of water on the windowsill where there was plenty of sun until I could get my grow bags ready. I used compost and bagged soil, planted the slips when they had started sprouting white roots on the stem. I made little hills and they were spaced according to the instructions that came
    With them. However, this was about 3 or 4 weeks ago and the green leaves on the top don’t look like they have grown. I always hear about sweet potato vines being super prolific and vines going everywhere… My leaves look green and healthy but they are still short and seem to be staying about the same
    Size as when I planted them, and I am
    Wondering does this mean that there are no tubers growing under the soil? I wish I could look under the soil and see if the potatoes are growing or not. How can I tell without digging one up? I don’t want
    To dig one up because they’re not ready obviously. Thank you!!!

    • If the plants remain green and healthy, be patient. If temperatures have been cool or very hot, the plants will need time to adjust to the outdoors. Keep the soil just moist. You can feed them a dilute solution of fish emulsion

  30. Hi. I grew Kumera slips but instead of planting them in the right time due to moving and having to create a new garden, I planted them out 3 months late . I knew they wouldn’t grow as way too late but thought I’d just do it anyway . The tips actually bloomed huge but then Autumn came . As I suspected no Kumera underneath but lush tops. I decided to keep it in till next year just to see. We had a surprise first which blackened off all the tops. Are they doomed or do you think I should persevere to see what happens or pull up and start again. Forever hopeful haha. Jo ps I’m in NZ

    • The frost has finished the season for this year; you can give them a couple of weeks to possibly produce new growth if you are bringing them into a greenhouse or indoors for winter. Otherwise, pull them up and plant again in spring.

  31. I planted sweet potato starts in late April. Good sunny location, consistent watering. BUT, we had a late-season frost in May. The sweet potatoes didn’t die but they’ve never gotten more than 4″ tall. Are they just goners?

    • Feed the plants with a dilute solution of fish emulsion or kelp meal. If you have another 100 frost-free days, it will be a good effort to try to pep them up. If your first frost comes in less than 100 days, try again next year.

  32. I have a sweet potato with toothpicks in water. It has a lot of roots and I see 1 plant about 5-6 inches long with leaves and 2 small ones growing also. Today I went to check it and the water looked very cloudy so I went to change water and it is very soft to where it feels it can be mashed up. What should I do?

    • It is time to transplant the rooted sections of the tuber into a potting mix; the tuber and roots may rot if left too long in the liquid. Separate the tuber so that each section has roots–then plant.

  33. Hello! I planted sweet potatoes a few years ago on a whim and was shocked at the great results but didn’t wait long enough for harvest. This year planted again and the vines were incredibly healthy and huge. We just tried to harvest and didn’t get ONE potato. So sad!! Why not? Any ideas? Sane garden, just put them in a different spot. Many other veg grew in the same soil. So upset!! :(. Thanks for all your helpful info!

    • The soil may be too rich in nitrogen; feed plants with a phosphorus-rich fertilizer such as 5-10-10. Space the plants at least 24 inches apart to ensure there is room for tuber growth.

  34. My mother and I decided to try planting a garden this year and devoted one whole garden box to sweet potatoes. We planted orange sweet potatoes but every single one of the potatoes has come out white! What causes this and is there anyway to fix it before we harvest the rest of the plants?

    • Check the variety of sweet potato that you planted. There are two types of sweet potato, one with golden skin and white flesh and the second with copper skin and orange flesh. This may explain the white flesh. Secondly, there are hybrid and heirloom varieties. If you planted a hybrid, the offspring may have reverted to a parent who had white flesh.

  35. Zone 7a, East Coast. I planted sweet potato slips back in June. They were slips from storebought s.p. that sprouted on their own. I’ve hilled them 3 times and watered them almost daily throughout June/July/to mid-August. At the point I began watering only every few days, checking the ground. Then we had rain off and on for a few weeks. a few flowers popped up, Very Cool! Around mid-September I decided to do a check figuring on 100+ days, let’s see what we’ve got. What I got were 1 thin s.p. and 2 other pencil thin s.p. After seeing the latter I assumed that I pulled too soon. I recovered the ground and replaced the vines. I waited another month-ish. I stopped watering the plants 2 weeks ago. The vines had once again begun to flower and had stretched beyond the bed. This weekend past I tried again… same thing. Pencil thin Sweet potatoes. I’m at a loss. What happened? I covered them and their vines again with more soil, watered them down. Is it worth it or should I harvest the leaves and flowers, call it done? I’m expecting frost in November, so I need to know what to do.

    • Sweet potatoes can grow long and stringy in heavy soil–soil that has clay. Your plants have run out of season this year. When you plant next year, be sure the soil is loamy but not too rich in nitrogen. Too much nitrogen in the soil will grow foliage at the expense of tubers. Also avoid overwatering. Once the plant is established and growing in loamy soil, watering once a week should suffice.

  36. Hi Steve –
    I have grown sweet potatoes for about 5 years here but do rotate. For the first time ever, had sweet potatoes rotten right in the ground when I harvested. They are in raised beds. It was a dry summer in the northeast US (no irrigation).
    Tubers looked normal, but one or two in several of the harvested clusters just fell apart – were total soft mush (about 50% of the body) although parts of same tuber were firm. The color was normal (Covington, so an orange variety).
    Any ideas?
    Thanks

    • The plants and their tubers may have suffered stress and some internal pithiness leading to rot or softness due to lack of irrigation–especially in a dry summer. Cell development may have been stunted. If you suspect disease or pests, you should move the sweet potatoes to a different bed next season. If you grow mono-crops in the same bed year after year, be sure you are amending the soil with aged compost and aged manure during the off-season.

  37. My sweet potato’s didn’t grow this year!! they are not more than 3 inches long and 2 inches wide. Can you still eat these??? they were in the ground for about 3-4 months…But I think my husband crowded them. Are they edible???? Thanks!!

    • Baby sweet potatoes can be roasted. Preheat the oven to 400F; toss the baby sweets in olive oil, honey and seasoning of your choice. Roast for 20 minutes then flip and roast another 10 to 15 minutes or until tender.

  38. Hi Steve
    This is the first I’ve planted sweet potatoes in a while. I left them in the ground too long and the mother roots rotted. As I was pulling everything up I noticed small sweet potatoes growing from the vine runners. They are about an inch in diameter and 4 inches long. Are these edible and if edible, are they tasted? It’s the only thing I’m getting from my efforts this year.

    • Young or baby sweet potatoes can be cooked like young or baby potatoes. Roasting covered with butter and seasoning is a good way to prepare young sweet potatoes.

  39. I planted sweet potatoes for two years now and have tried digging but I wouldn’t see anything and the leaves of my potatoes have never turned yellow but I still left the potato since I thought maybe it would have something in it

    • The likely reason a sweet potato plant does not form tubers is too much nitrogen in the soil. Avoid high nitrogen fertilizers. Use a 0-5-5 or 5-10-10 fertilizer.

    • The plants are in need of nitrogen. Get them into sunlight for 8 hours a day and feed them with a 10-10-10 organic fertilizer until the leaves turn bright to dark green, then feed them with a 5-10-10 fertilizer until harvest time. The spots will not go away but if the plant gets nutrients it will replace the damaged leaves with new leaves in about 6 weeks. Don’t trim away the damaged leaves until the new leaves begin to mature. Keep the soil just moist, do not over or under water.

    • You can gently push soil over the exposed sweet potato tubers and keep them buried until harvest. Exposed sweet potato tubers can be eaten. Sweet potatoes do not produce solanine like potatoes. When a potato tuber is exposed to light it turns green and produces solanine which is a poisonous compound; that is not the case with sweet potatoes.

  40. Hi! I live in Los Angeles and planted my sweet potatoes from slips I grew myself. I planted them in March, but the vines are now only about 2-3 feet long — they were shaded a lot of the summer by other plants. I know I should harvest before the frost — but we don’t have a frost! I know I should harvest according to the package growing length — but I don’t have a package. Harvest now? Wait until vines are more vigorous? Advice? Thanks so much!!

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