in ,

Radish Growing Problems: Troubleshooting

Radish growing problems
Lifting radishes as soon as they are large enough to eat is important. Radishes that stay too long in the garden will become woody.

Radishes are a cool weather crop that will tolerate some heat.

Sow radishes in the garden as soon as the soil can be worked in spring and plant succession crops every 10 days until the end of spring.

Lifting radishes as soon as they are large enough to eat is important. Radishes that stay too long in the garden will become woody.

Radishes germinate readily and grow rapidly so don’t sow radishes too thickly and thin seedlings right away so that they don’t stand closer than 1½ inches apart.

Radish Growing Problems and Solutions:

• Roots fail to form. Seed are sown too thickly. Thin radishes early and harvest roots as soon as they are large enough to eat. Thin seedlings to 1½ to 2 inches apart.

• Seeds rot or seedlings collapse with dark water-soaked stems as soon as they appear. Damping off is a fungus that lives in the soil, particularly where humidity is high. Do not plant in cold, moist soil. Make sure soil is well drained.

• Tiny 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.

• Pale yellow, gray spot on leaves appear water-soaked spots; spot become circular with gray centers. Leaf spot or Septoria leaf spot is a fungus disease. Add organic matter and make sure planting bed is well drained. Remove and destroy infected leaves and plants. Rotate crops. Keep garden free of plant debris.

• Leaves have whitish or yellowish spots; leaves are deformed; plants wilt. Harlequin bugs are black with bright red yellow or orange markings. They suck fluids from plant tissue. Handpick and destroy bugs and egg masses. Keep garden free of crop residue and weeds where bugs breed.

• Leaves turn dull yellow, curl, and become brittle; plants yellow and are stunted. Aster yellows is a mycoplasma disease spread by leafhoppers. Remove infected plants. Control leafhopper. Keep the garden free of weeds which can harbor disease.

• Leaves have pale green spots on the upper sides and violet-colored downy growth on undersides. Downy mildew is caused by a fungus. Avoid overcrowding; improve air circulation. Avoid overhead watering. Remove and destroy infected plants. Keep garden free of plant debris. Rotate crops.

• Lower leaves cup or roll, lose their dark green color and become streaked and leathery; brown speckling at the stem end of roots. Leafroll virus is transmitted primarily by aphids. Control aphids. Remove diseased plants and weeds.

• Leaves yellow; plants wilt and appear weak; sunken, red oval spots at base of stem; roots have red spots or streaks; plants turn brown and decay. Rhizoctonia or Fusarium root or stem rot is a fungal disease that favors warm soil. Remove infected plants and plant debris that harbor fungus. Rotate crops. Be sure transplants are not diseased. Rotate crops regularly. Solarize the soil in late spring or summer.

• Leaves yellow between veins; leaf margins brown and curl upward; stem base becomes dark brown, black, and slimy; roots become slimy brown-black at stem end. Blackleg is a fungal disease. Add organic matter to planting bed; make sure soil is well-drained. Rotate crops.

• Tunnels and grooves in roots; leaves become faded. Root maggots are small gray-white, legless worms to ⅓-inch long; adult looks like a housefly. Flies lay eggs in the soil near the seedling or plant. Apply lime or wood ashes around the base of plants; time planting to avoid insect growth cycle. Plant a bit later when the weather is drier.

• Roots are hot tasting and pungent. Soil is too dry or soil temperature is too hot, above 90°F. Protect roots and cool soil with 2 to 3 inches of organic mulch. Water radishes 2 to 3 hours at a time; do not water again until the soil has dried out to a depth of 4 inches.

• Roots are woody and pithy. Soil temperature is too high or watering has been spotty. Keep roots covered with soil or mulch to avoid soil warming. Keep radishes evenly moist through the growing season; do not allow them to dry out. Harvest roots as soon as the roots are big enough to eat. Do not let radishes sit in the garden.

• Roots are cracked. Harvest radishes before the reach full size for best flavor and to avoid cracking. Radishes in the ground too long may crack. Cracked roots are susceptible to fungal disease.

Radish Growing Success Tips:

Planting. Radishes grow best in full sun. Plant radishes in the partial shade of taller crops where the weather is very warm. Grow radishes in loose, well-drained soil. Turn the soil to at least 12 inches deep before planting long-rooted radishes.

Planting time. Sow radishes in the garden as early as 5 weeks before the average last frost date in spring. For a continuous supply, sow radishes every 7 to 10 days. Stop planting radishes when daytime temperatures average greater than 80°F. Radishes do not grow well in hot weather; they will become pithy and pungent flavored. For a fall crop, sow radishes so that they come to maturity before the first average frost date in autumn. Daikon is well suited for a fall crop.

Care. Radishes require consistent even moisture for quick growth. Thin radishes shortly after seedlings emerge; radishes are quick growers and need spacing of 1½ inches between seedlings for quick root growth. (Thinned leaves and roots can be eaten in salads.) Keep planting beds weed free. Add aged compost to radish planting beds on a regular basis. Spread age compost or organic mulch across planting beds to keep the shoulders of maturing radishes well covered and cool.

Harvest. Lift radishes when they are young and tasty. Spring radishes are best when they are no more than 1 inch in diameter. Winter radishes and daikon can be lifted as you need them until the first frost, but be sure to protect them from cold weather; add a layer of straw mulch or compost.

More tips: How to Grow Radishes.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

GIPHY App Key not set. Please check settings

73 Comments

    • Pluck one from the soil and cut in to it. Discolored radish roots can be a sign of root rot. Root rot is caused by various fungi, so you want to look at the seed store for rot resistant varieties. That said, some radish varieties–such as Japanese varieties–are white. The seed packet should show you a picture of what your radishes should look like at maturity.

  1. Hi Steve, I love your website.
    Yesterday I received 2 bunches of fresh radishes from our organic delivery service but they look very strange and I don’t know if they are safe to eat: the roots have wart-like whitish bumps and some roots are wery strange and deformed in general. These “warts” especially don’t look appetizing. I will talk with the farmer but first want to be equpped with some knowledge :-). Can you help? Thanks so much!

    • Your farmer has probably given you an answer. Some root crops can appear deformed if they are growing in soil that is not wholly loamy, that has small rocks or impediments that growing roots bump up against.

        • Check the variety; there are radishes with long, white roots such as White Icicle and Daikon. If the variety is supposed to grow a round bulb, the plants may have needed thinning early on and there is insufficient room for bulb development.

    • If your radishes are blooming they are well past harvest. If the roots were very small and the tops were quite large, your soil is too rich in nitrogen and phosphorus and potassium poor. Add plenty of compost to your planting beds–2 to 4 inches each year–this will help balance the nutrients. Steady even watering is essential for radish root growth. Keep the soil evenly moist for the 25 or so days required to grow radishes.

    • Flowers and seed pods are edible, and taste similar to the roots. I love to use the seed pods in stir fries. Flowers are also beneficial to other plants as they attract beneficial insects. You can’t eat the roots anymore but I would keep at least one of them for the flowers/seed pods.

  2. I have radishes that have rubbery roots, wilted dried out tops and have little to no root hair development. they are grown in sandy soil and are watered weekly. I’ve grown 2-3 different varieties but only one has this problem. Any ideas? Thanks!

    • Radishes require a steady supply of water. You can not let the soil get too hot–cover the surface with a few inches or organic mulch. Be sure to check radishes every few days and harvest them before they exceed 1 inch in diameter. In the off season add plenty of aged compost to your planting beds.

    • If your plants sprouted but stopped growing you might want to add an organic source of nitrogen to your soil. A relatively quick fix would be to water with kelp or fish emulsion or sprinkle kelp meal around your plants and water it in. Adding aged compost to your planting beds twice a year is another way to add nitrogen and other nutrients to your soil. Radishes are generally a light feeder and don’t require much. If you are confident the soil is rich in nutrients, air or soil temperature might be slowing down your seedlings–cover the growing bed with a plastic tunnel for a few weeks to warm the soil and plants.

  3. My radishes are all leaf and hardly no radishes right size the few I have got but small and dry tasting even though I water them often.

    • Radishes do not grow well in temperatures greater than 75F. They grow best in spring and again in late summer and on into early autumn. All leaf and small bulb formation could be the result of high nitrogen content in the soil. Prepare your radish planting bed with plenty of aged compost–radishes don’t need much more in the way of nutrients because they are light feeders. Make sure the soil stays moist and does not dry out during the growing time.

  4. I planted radishes about a month ago. They sprouted quickly, but are still small. The second leaf has developed and is green but the first leaf has turned yellow. The sprout still seems small for one month of planting, but I have never planted vegetables before. Unfortunately my location does not provide a lot of sun, could the yellow leaves be due to lack of sun exposure or over watering? Is it normal after one month of planting the sprout is still weak with only the second leaves forming? Thanks

    • Commonly radishes are ready for harvest within about 30 or so days of sowing seed. If your sprouts are not growing it could be lack of sunlight–your radishes will need at least 6 hours of direct sun each day. Too much or not enough water can cause leaves to yellow and die. Temperature is also an important factor–temperatures too hot or too cold can slow the growth of vegetables, including radishes. Since you are a new vegetable gardener you can chalk up this planting to experience: keep a journal of when and where you plant and the results; if the results do not match your expectations then you can work with the variables–that is, next time plant in a location with more sun. If sun is not readily available because of location, try planting in containers which will allow your to move your garden around as the year progresses. Radishes are an excellent crop to grow for new vegetable gardeners because the days to harvest are so short–you can gain a lot of experience in a short amount of time.

  5. My radish plant has the leaves being eaten (I am growing it for flowers and seeds pods, not roots). There is no sign of yellowing, withering, or curling, just large holes in the leaves. Holes are up to 1 inch wide. What might be causing this?

    • Slugs and/or similar pests: I had the same issue, realized it too late so I had to pull what was edible from the bed, till the soil, spray Sevin dust; 7 days later I added small amounts of compost and other amendments… then I put a salt barrier around the outskirts of my garden. 7 day process but haven’t had a problem since

    • There are a few possible reasons for your radish root problems: (1) roots will be small if the the crop was not thinned; allow an inch or more for each root to develop; (2) inconsistent soil moisture can cause radish roots to underdevelop or be spindly; (3) hot weather or hot soil can hinder radish root development–time your planting so that roots develop when soil is cool. As for the bites–radish leaves can be attacked by harlequin bugs; radish roots can be scarred or tunneled by maggots–to avoid cabbage maggots, plant early in spring (the maggots are the offspring of the cabbage maggot fly; you can exclude the flies from your crop by placing a row cover over the plants.

  6. What eats the tops of my growing radish before and during harvest? Leaves are ok, just the top of the growing fruit.What can I do to avoid this please? Hev

    • Radishes have the best flavor when they are lifted at the peak of maturity–basically on or about the number of days from sowing to harvest maturity for the particular variety being grown. If a radish is lifted in its prime it will have a mild flavor with a hint to zing; if left in the ground too long it will become corky and pity and may become very hot to taste or mealy and bland. Radishes prefer cool weather and just moist, loamy soil so that they mature quickly. The best way to know if radishes in the garden are ready for harvest is to lift one and taste it; when the taste is right lift all of the radishes planted at the same time. For a succession of harvest, sow seeds every five days or so–sow just enough for each harvest.

  7. Hi im having problems where my radishes, they r dying when young 4 leaf stage, those that survived have root rot n dont fully form, what problem is this n how to treat it pls?, some say its powdery mildew but there is no powder, the problem is the radish not forming or growing as they should b, u get cracks since young, i feel hopeless

    • There are a few possible reasons for the radishes dying at an early stage; you may need to do a bit of detective work to find the exact reason. Here are the possibilities: (1) not enough soil moisture; keep the soil evenly moist especially early on; (2) soil is too wet; (3) the soil is infected with a fungal or bacterial disease; commonly the fungal disease known as damping off can attack young seedlings; you can remove the top several inches of soil in the planting bed and replace it with new planting mix, or you can sow the radishes in a different bed. Avoid crowding seedlings; thin early and encourage good air circulation which can stem damping off.

  8. Mt radishes looked fine from the ground up, but they did not grow underground. Everything else in the garden was fine. Can you help? (Thanks for the site!)

    • There are a few possible reasons your radishes did not form bulbs: (1) the seed and seedlings are too closely spaced; once seedlings germinate thin plants to 2 to 3 inches apart; this will allow bulbs to develop; (2) too much nitrogen in the soil; nitrogen promotes green leafy growth, not root growth; avoid feeding radishes until they are 2 or more inches tall then use a phosphorus-rich fertilizer such as 5-10-10; (3) the soil is too hard; be sure to sow radish seed in loamy, fluffy soil; (4) not enough sun; grow radishes in full sun.

    • Radishes grow best and quickly in cool weather. Radishes that are too hot have likely been grown in weather (and soil) that is too warm and/or they have been in the ground too long. Globe-shaped radishes will be mild tasting if they are grown quickly in cool weather. Note the days to maturity for the variety you are growing and mark on your calendar the date of planting and the date of maturity; harvest at maturity–don’t wait longer, even if the radishes are small. Thin radish seedlings so they grow 3 to 4 inches apart and have plenty of room for root development. Keep the soil just moist throughout the growing period.

  9. Something is taking circular bites out of the mature radish. The interior is not affected.They taste just fine but are not pretty. I am guessing there is something in the soil possibly, feeding nocturnally.Stumped in Seattle

    • Several pests can eat holes in mature radish roots. Cabbage maggots, adults and larvae of vegetable weevils, and harlequin beetles can infest radishes, eating holes in their leaves, stems, and roots. Cover seed beds and seedlings with floating row covers to prevent insects from getting to the plants. Sprinkling diatomaceous earth, wood ashes, hot pepper or ginger powder around the base of plants may also control these pests.

    • Newly germinated radishes produce very tiny white root hairs that develop into more substantial roots; sometimes these root hairs are mistaken for mold or fungal growth. So what you describe, may not be fungal growth or mold but developing roots. That the radishes are uprooted each morning is concerning. Place a floating row cover over the planting bed to exclude birds, small animals, or other pests that may be dining on the succulent new growth. If you suspect that the “cotton-like stuff” is mold or fungal growth, replant in a new planting bed; use a commercial organic planting mix to ensure that soil is disease free.

  10. Hi,

    I’ve just transplanted my radish seedlings early this morning, however now it’s afternoon and the seedlings have wilted.. Is this normal? The spot I planted in gets a lot of done but only from around 11am.

    • The wilt after transplanting is called transplant shock. Radishes are very shallow-rooted; it is easy to disturb the roots when transplanting. The plants should snap back if the roots were not seriously injured. Transplant seedlings in the late afternoon when they will not have to endure afternoon sun–or place a frame and a piece of shade cloth over the plants to protect them from direct sun for a few days. Be sure to give transplants a drink of water after transplanting.

    • Thinning is a term used by gardeners meaning to cull or eliminate some seedlings or plants so that those that remain have room to grow to maturity. So, for example, when you sow radish seeds–which are very, very small–it is difficult to sow them at the recommended distance. Often several radish seedlings will germinate in an inch of row–that is too many. Radishes should be thinned from 1 to 2 inches apart; that way the plants that remain will be able to develop full roots and reach mature size.

    • It may be that the radish stems and leaves are being eaten by a soil-borne pest–cutworms, some battles, slugs, snails. Spread diatomaceous earth around the radishes–this is a barrier to most soil-dwelling pests.

  11. i just planted some french radishes, and i started them indoors then transplanted them outside. they are fine and growing well, but their stems are long and some are fallen over on their side and still growing. did i not put the seedlings in deep enough in the soil because i transplanted them? i have some that i sowed directly in the ground that seem fine but i was wondering if i’ll still get a bulb from the sideways ones.

    • The seedlings started indoors may have been inside a bit too long; the stems grew long as the leaves stretched for sunlight. The radishes started outdoors have had the sunlight they need and so they are growing stout and strong.

      • I am having the same issue with radish stems growing sideways, with big leaves and no bulbs. Planted outdoors in containers and I suspect I didn’t thin them enough so the leaves were trying to reach for sunlight? Thank you for all these helpful tips!

  12. My radish plants seem healthy, they are small but the leaves are a mix of dark green and dark red color, but the leaves seem to be healthy. No wilting or cupping. Any idea?

    • It is not uncommon for leaves of many plants to turn red in reaction to cold temperatures. On a less positive note, the base of radish stems and roots can become red-streaked when infected with Rhizoctonia or Fusarium root (stem rot).

  13. I placed a daikon radish top in water and the leaves flourished but no roots though. The cut off surfaced was also slimy and turned dark. Given that the leaves were flourishing, i decided to plant it in starting soil with some vermicast but in a few hours, the leaves start to droop and wilted. Do you know why this is happening? I live in the tropics in Singapore. Could it be a weather issue or should i have tried to grow the top in soil in the first place?

    • If the weather is warmer than 75F (23C) the radish will not thrive. Replant when the weather is cooler, and, yes, replant in potting soil; vermicast may have been too rich in nitrogen.

      • Our weather here is typically between 33-35 deg year round. Could i replant it and keep it under shade? Do they need sunlight to thrive?

        • Temperatures of 33-35C/91-95F are too warm for radish growth success. You can try growing radishes in the shade but it will be difficult.

  14. I plant my radishes at the depth stated on my seed packets yet more then half of them are stretching over the top of the soil like they are reaching towards the light! What is going on? Should I be planting them deeper or covering them with soil when this happens? They do this and then are not forming bulbs.

    • When seedlings are 1 inch tall thin them to 2-3 inches apart so they are not crowded; be sure they are getting plenty of sunlight; do not overwater; do not feed them nitrogen.

  15. My leaves are turning a pale red. I picked off that growth to allow for new leaves but the new leaves are turning purple/red around the edges. Any ideas? 🙏

    • Feed the plants with a high phosphorus fertilizer such as 5-10-10. Next time you plant, make sure the soil is well-drained. If the soil is compacted there can be low levels of soil oxygen which can result in leaves turning red.

  16. I have transplanted my radish seedlings. The leaves are getting holes (probably eaten away by something). I have got mint with white fly infestation and a cherry tree with some pests (eating the leaves). I have tried using paraffin oil organic spray. Is not working. Please help, what’s the likely cause and solution? Thanks

  17. I planted my watermelon radish seeds in an outdoor raised container with sterilized soil and fertilizer. They were covered with a plastic top, exposed to plenty of sun and were watered well. The leaves grew lush, and the roots looked healthy. But the radish itself was small, more oval than round, and the fleshes tunneled through. This is the first time I’ve ever gardened. What to do?

    • Radishes will be small if the plants were not thinned. For watermelon radish allow 4 to 5 inches between each plant; this will allow each root to grow to about 3 inches across. If a root is tough or is pithy (this may be what you describe as “tunneled through” the cause is commonly (1) insufficient soil moisture, (2) hot weather, (3) harvest too late, a week or more past the date of maturity. Tunneling in roots can also be caused by larvae of flies that eat their way through roots; the tunnels would be discolored. Cover the crop with a row cover to prevent flies from laying eggs in the soil.

  18. Hello Steve. Wondering if you can help me with this. I am battling white grubs. I’m thinking of planting radish as a trap crop for the GRUBS…not the beetles. Battling the beetles is a whole different story. I’m on 85 acres, new property, not much biodiversity…. I have been applying milky spore and turning the soil multiple times when the grubs/larvae are near the surface and hand picking. I’m wanting to grow a variety of plants in these raised beds… potatoes, garlic, beets, cabbage, squash, etc… but hesitate because from past experience, know if I don’t put in established transplants they will eat the roots of these plants b4 they stand a chance. and even then they have weakened and stifled plant growth due to consumption of the roots. I’m wanting to plant from seed more on certain crops. I understand grubs do not to feed on the roots of peas, beans and clover. I’m not sure which direction to go in … to either try to surround the planting bed with “undesirable” plant material and pray they don’t cross that barrier and leave my other crops alone …. OR …. do I plant a trap crop that they enjoy feeding on their roots. I know they love rye & KY grass…but don’t want to plant grass in the raised bed. I could use radish as a cover crop…but don’t know if they are attracted to their roots or not. You seem very knowledgeable… and it’s been difficult to research this topic…wondering what your thoughts are. Thank you so much for your time and for deciphering my dilemma. . Stay safe / Happy gardening.

    • The grub control strategy you use will depend to a great extent on the time of the year you want to begin controlling the grubs. If it is autumn where you live, you can turn the soil now and over the course of the next month or two to expose the grubs to predators and cold air. That is a simple organic solution; that also assumes you can allow the ground to remain fallow until spring. If it is spring where you are, then you can (1) use the same method as above; allowing predators to eat the exposed grubs, but you will need to delay crop planting; (2) apply beneficial nematodes to the area; (3) plant trap crops such as ryegrass in strips or blocks through the garden; the grubs will move toward the trap crop; (4) grow the crops undercover a row cover to exclude egg-laying adults. You may want to consult with an agronomist at the nearby Cooperative Extension for specific controls in your area.

    • The plant was likely attacked by a cutworm; these are larvae of a moth that lays its eggs in the soil. The best defense to exclude the moth from the planting bed. When you plant seed, cover the bed or row with a row cover. Let the row cover remain in place until the plants are 4 inches (10cm) tall. If you suspect other pests such as earwigs of slugs, sprinkle diatomaceous earth around each plant to protect them.

  19. “Something” ate the leaves of off two of my radish seedlings. I can see the stems sticking out of the ground. Are the radishes “toast” or will they continue to mature? Trying to figure out oof I should pull them and plant more seeds. Thank you.

    • The leaves were likely eaten by an earwig, slug, or snail. If there is no green leaf left, the seedling will likely wither. Replant now–you have not lost much time. Sprinkle diatomaceous earth around your seedlings; this is a barrier to keep soil crawling insects away from seedlings.

Spinach Growing Problems: Troubleshooting

Cabbage Growing Problems: Troubleshooting