Try planting them 6 inches apart. Worked for me.

I wish I knew the answer to that. In my Dad's garden, where the soil had quite a lot of clay, there was never a failure with radishes. As you say, they were the easiest crop to grow. Now, in sandy soil, I sometimes have a failure. But not always. Numerous others report the same problem here every year under all sorts of growing conditions. It's baffling.

Jim

It could be a Boron deficiency. Run a soil test and have them check it for Boron. Boron is needed in a small amount, but it is very important for the formation of root veggies. About spacing, I plant 6-8 rows in a 3 foot bed. I always have radishes.

Jay

I haven't had the soil tested in these beds but have a sample ready to send to the lab. When I had other samples done of soils in the area there was never a boron deficiency. But then things can change over time. Thanks for that tip.

Years ago when I was gardening in a different location I had decent crops of radishes. Six inches apart seems excessive but I'll give it a try next spring. I'll try just about anything at this point. Thanks!

Sandy

Six inches apart seems excessive

I grow big radishes. :)

I cannot grow small spring radishes, you know, the red balls or white icicles, but I grow terrific huge fall Asian radishes. I'm a very experienced gardener--over 45 years of gardening, and I can't figure it out.

Happyday, that makes more sense. I've never tried the big radishes, always the Cherry Belles and such. Laceyvail, I've been gardening as long as you have and teach veggie gardening classes and it's just plain frustrating. I really should know how to grow this seemingly simple crop. (It's doubly embarrassing that my novice gardener daughter and her two small children have grown beautiful radishes the last couple of years!)

I might have to give the Asians a try next spring. Are they as tasty as the little ones? Which varieties do you recommend?

I put out some Easter Egg radishes in March in my garden. I thinned them some but left the plants just enough room for the root. The plants grew quickly and made a nice root.

I think my success was partially due to the radishes being in a location that had lots of water. The radishes were under the edge of a roof so when it rained, they received lots of water. It also rained frequently in March and April so the soil never got dry. The temperatures were also cool, staying in the 60s and 70s while they were growing.

My guess is inadequate nutrition, specifically N early.

Dan

gardener sandy, I too have taught gardening classes. I love the big Asian radishes and consider them a major fall crop. I grow a Daikon variety I get from Johnny's Selected Seeds (can't remember the variety name), and also Green heart (seed from Pinetree). Green heart is long and large and hotter than Daikon. I also grow a large round watermelon type (Green outside and red inside), also somewhat hotter than daikon. They all store for a very, very long time in the veggie drawer in the fridge. A favorite recipe, of which I can eat gallons, is very coarsely grated radish (daikon or other) with a lesser amount of coarsely grated carrot. Salt (about 1 tsp to four cups of veggie). Let sit to draw out liquid. Drain. Add rice vinegar and a little sugar. I sow the radishes here in zone 6 in early August.

In the past I thought the answer is early thinning and ample watering. Some of what I read above contradicts those ideas. I am now wondering if it has more to do with soil type.

Could we have a poll of those reading this thread to see if there is a correlation with soil type?

I'll start:

My previous soil was clayey loam. No failures.

My present soil is loamy sand. Occasional failures.

Jim

Clayey soil: Radishes work for me, even when crowded.
Potting soil: Perpetual failure :)

Haven't gardened in sandy soil.

I also recommend 'German Giant'. Although they are supposed to get baseball sized, I always pick them at the size I would pick cherry belles, and they reliably reach that size in 3-4 weeks. They taste very mild, but not insipid.

My soil is clay but has compost mixed in. The area where I planted radishes had a lot of rocks. I don't have any place that is not clay based. The subsoil is hard clay and rocks.

Interesting. I've had radish failures too, but I've done very well with turnips for some reason.

Is there a natural way to add boron? What kind of additive to the compost?

My soil is clay but has compost mixed in. The area where I planted radishes had a lot of rocks. I don't have any place that is not clay based. The subsoil is hard clay and rocks.

I could not grow radishes in the ground that were not wormy without large doses of Diazanon...didn't like that. Some years ago, I started growing nice crops of French Breakfast and a nice Pink variety in pots. I use regular potting soil from the local nursery (Pro Mix, etc)and cover the pots with a row cover material. . I get four or five crops a season in the same pots. A little fish/seaweed emulsion and a bit of time release ferilizer is added irregularly. Regular watering and a sunny location complete the formula. This might work for you.
Victor

twc015,

If I read your posts correctly, your results are:

Clay soil. No failures.

misummergarden,

Your soil type? Occasional failures? All failures? Other?

Jim

Loamy clay. Its rocky hardpan that I've broken up and worked bunches of compost into.

I've never really gotten a radish harvest. In the potting soil bed, I planted them crowded, and there were no bulbs. Out back in the loamy clay they kept disappearing, I think because of critters. They'd just be getting started and bam! they were gone. So maybe they'd have done well if they hadn't been eaten first.

So I can see some common threads here.

I've grown enormous French Breakfast, big Purple Plum, softball sized Spanish Black and Watermelon radishes. Have only grown small to average Diakon, maybe I don't have the right seeds but I get 1 to 1.5 inch thick, long like a narrow carrot white Diakons and not the baseball bat sized tubers you see in Japanese cartoons.

I spray with Miracle Grow, think it has boron in it. The advice about keeping it cold and wet is correct. Start radishes right away in early spring, they are done by summer.

I've grown good turnips too but the wireworms (clickbeetle larvae) find them and the Sevin I spray with the Miracle Grow does not get them underground. :(

Yes, my soil is clay. Another thing I noticed was that some of the seeds I set out did not come up until about a month after the others, and these did not form roots. They went straight to flowering. This was probably due to the temperatures moving into the 80s while they were growing but the other radishes matured when the temperatures were still in the 70s.

Go easy on the boron, folks. IIRC, too much is as bad as not enough and very little is needed. Furthermore, boron deficiency is rare. So, in most cases, adding boron will not solve your problem.

It's a little off topic for this thread but cabbage root maggots often are a problem in my radishes. A positive solution to that is floating row cover, which keeps the adult (a small fly) from laying eggs on the plants.

French Breakfast is reputed to do better than other varieties in warm weather. My experience bears that out.

Now, back to the problem of failure to "bulb up". It would be really great to find a solution to that. If you haven't participated in the poll, please do.

Your soil type? Occasional failures? All failures? Other?

Jim

The soil in the current bed is clay that's been amended heavily with compost and some chunky peat moss (not the typical baled peat.) I fertilize the bed lightly two to three times a year with 10-10-10. This batch has made one bulb in the whole bunch but the tops are lush. I suspect for this particular crop there was too much nitrogen in the soil. It also may have been too hot when they were started. We had some cool fall weather but then it turned back to typical summery temperatures soon after they sprouted. I don't know if that's part of the problem or not. Now that it's dependably cool I may try another small batch, just as an experiment.

Sandy

Bottom land heavy black sand loam here. Very few failures on bulbing up as long as the weather is cool and wet. Now in the mels mix I seem to have trouble with keeping the seeds damp for germinating, One watering a day does not cut it. I could be spoiled by my moisture holding soil. It does hold like clay due to a high water table. Average of 3-foot depth on my lot.

Curt

If they rush to flower, you know it's too hot. But, let them flower and eat the hundreds of little seed pods instead! They are enjoyed with beer in Germany. You probably get more vegetable from the pods than from the bulbs.

Good to know, happyday. I understand the foliage can be eaten but is not very tasty. Anybody tried it?

Sandy

I have a back yard with many types of "soil" trying to see what works for me. The radishes I planted were all the little red ones or the white tapered ones. I tried everywhere in the garden,
Sandyloam with organic mat, no good at all
heavy clay soil with organic mat, ok but pretty small
pure homemade compost, clear winner big juicy roots.
I don't know if that helps. All of them had about the same sun and water and all were planted close to pepper plants and my pepper plants did about the same so its more composting for me.lol. :o)Deanna

"I understand the foliage can be eaten but is not very tasty. Anybody tried it?"

Radish leaves are my nomination for underappreciated vegetable. They are very good as the green element in a clear soup such as won ton. Despite the hairiness of the leaves, which disappears when cooked, I found radish leaves good in salads and sandwiches.

Jim

I'm thinking of an experiment to see how soil type correlates with bulbing up of radishes. I would plant radishes in containers or a set of small raised beds filled with different types of soil and treated the same in all other respects. I would make the soils, at least most of them, extreme. i.e. very sandy, high humus, very clayey, etc.

Any suggestions?

Jim

Hey Jim,
If space permits, perhaps do the experiment twice. One with normal spacing and the other with tight spacing :)

I grow only in containers. Every container has a different mix. In one container, I had 2 giant radishes. The smaller one has a leaf that measures 16" from base to tip. This is a crimson Giant, most of which are small.

Interesting suggestion, drhorticulture. I'll keep it in mind. Several possible factors are suspected of causing failure to bulb up. My experiment will have to focus on one or two. I would like to have opinions on which ONE is the likely culprit:

1. soil type

2. spacing/thinniing

3. water/irrigation

4. nutrition

5. other

Jim

My late crop that didn't produce bulbs did have very large and lush top growth. To me that indicates it might be excess nitrogen. Since everything else was on target (except for a bit of summery heat early on in their growth) I vote for nutrition as being the most likely culprit.

Has anyone grown radishes indoors under lights in the winter? I was thinking about experimenting with some bought potting soil of known nutrient content, using some straight from the bag and adding a bit of nitrogen fertilizer to the rest of it. But I don't have an especially good place to do this indoors so I might wait till spring and try it outside in containers.

Sandy

"To me that indicates it might be excess nitrogen."

Did you apply an amount of nitrogen that makes you think it could have caused that? I ask because, it seems to me, nitrogen is too often demonized.

Jim

I used 10-10-10 three times over the summer, the last time being probably in August. I applied it at the rate recommended on the bag. I've always been led to believe that lush leafy growth and little fruiting (such as with tomatoes) could be the result of excess nitrogen. These radishes (which are still in the garden) are very dark green and the tops are huge in comparison to others I've grown that formed a bulb.

Without scientific testing I guess there's no way to know the cause for sure.

Sandy

In principle, excess nitrogen boosts foliage at the expense of fruiting. I just think there is a tendency to overrate that effect and be stingy with nitrogen. Too much nitrogen may explain your situation, however. It does seem that way.

Jim

Keep the soil neutral (7) on the pH level. Also, radishes love sandy loams... mix in sand if available to you. (Not required though). A lot of time when the radishes don't produce bulbs, it is due to PESTS. Root maggots can cause them not to bulb. Usually, growing close together isn't going to cause them NOT to bulb, but yet cause a deformity in the bulb as they press against each other.

Here is a link that might be useful: Radish Garden - Healthy Snacks, Recipes, Growing & Preservation

radishking,
How to prevent pests? Root maggots?

I love radish greens. My favorite dish happened one day when I sliced radishes in half lengthwise and tossed them into the pot to cook with a pork roast. Yum. However, I also like them sauteed with other veggies like carrots and onions or whatever.

Soil Type: Heavy clay loam, slightly alkaline. Compost mixed into the soil but never chemical fertilizers.

Radishes are the first seeds I put in the ground in spring. Never get failures on early seedings, later staggered seedings sometimes fail. Fall seedings are a crapshoot but I always do it anyway. Winter radish varieties are less successful for me than the common spring varieties.

I water occasionally if needed. I mulch radishes with decomposing straw and never fertilize. It has been my experience that the N in the ferts increases foliage at the expense of root development regarding root vegetables.

Favorite Spring Radish Eats: Chopped radishes, chopped parsnips, and chopped wild ramps mixed in the burger for juicy, zesty wood-grilled hamburgers topped with sauteed morel mushrooms and swiss cheese, with a side of grilled fiddlehead ferns. Try ordering that at the local drive-thru. ;-)

-Tom

Hey everyone. This was a very helpful thread! I just tried to harvest my first radish (Cherry Belle). It's actually the first time I've ever grown them in my garden. The leaves look great, but there was no bulb, only a long root. So disappointing! :-( I'm pretty sure there is no nitrogen deficiency in my soil. I tilled in compost in the fall, and I use nearly finished compost as mulch in my garden. I also use blood meal as a nitrogen source.
I'm pretty sure my problem was a result of inadequate spacing. They are probably around an inch apart, some (blush) maybe even less. My delicious spinach and recently planted tomatoes and cukes are doing great!

This is the second year I'm planting radishes and I've had the same luck all of them are bolting it grows a strait purple stem without getting fat (bulb)?

I live in NYC and the temp are now between 50-70 (rather generally in the 60's) ,I water them daily ,I used miracle grow seed starting potting mix around the seed and the rest of the flower pot regular top soil

Does anyone have any recommendations for me ,or at least had some success in the same zone/situation ?

I have the same problems as many posters, my radishes fail to bulb up. I planted them early this year and spaced them more than usual, still no luck. I am considering trying a bulb fertilizer or something higher in potassium or phosphorus.

On the subject of eating them, when you thin your radishes, the baby greens are fantastic micro greens. Its a lot of work, but since you have to thin anyway, you might as well get something out of it.

I planted a mixed radish seed pack. Some are obviously bulbing up now even above the soil I can see a bulb about 1/2 in across. What I dont know is how to tell when I should start harvesting them. I sowed the seed about a month ago. Because it is a mix, I have no idea how big they are supposed to get. I also have some watermelon radish going, but no sign of bulbing yet on those.

I have found that temps make all the difference in radish success or failure. Get the things in early enough in the spring and and they do well. Too late and they bolt & it is a COMPLETE waste of time. My fall crop seems to always do well & is even tastier than the spring planting. Soil is clay with some additives to make it soak up water better. I water about every 5 days or so. As far as fertilizer goes, I don`t use it on the radishes. Spacing is around 1 inch or less.

Soil: Sandy Loam, pH: 7.8

Have only had a complete failure bulbing up once, that was with black spanish. Never grew them again, but read where they do better as fall radishes--plant warm, let weather cool down as they grow. I don't thin--just sprinkle seed in the row and pull the first ones ready "thins" the rest a little, but they are already bulbing up, just slower. As a result, they tend to grow like hair on a dogs back.

Sometimes I have more that will end up never bulbing up, sometimes very few. They are among the earliest things I plant. I've been wanting to plant the radishes and a lot of other things for the last month and haven't gotten there yet--weather just plain wet so I can't get in the garden, and this weekend is called due to rain, also. I've felt that later radishes often have a harder time bulbing up, whether it is the warmer weather or maybe day length could be a factor. Sometimes I wonder if it doesn't have something to do with seed quality or source.

When radishes bolt, you will actually get more vegetable from the fresh seedpods or rattail radishes than you would have gotten from the bulb. The plant will get to 3 feet or more and may need to be staked.

beeone I have sandy loam with lower pH, no soil test in two years. I had Black Spanish & they were hot for my taste, in large amounts. So I let them grow & they got as big as turnips/tennis balls. They were still hard, not pithy or soft. Thanks for the details on your radishes.