Plant garden radishes by sowing seed as soon as the soil can be worked in spring, once it no longer sticks to the tools. Set the seed a quarter to a half inch deep, and do not wait until the bed is already hot.
Sow as soon as the soil can be worked, a quarter to a half inch deep
| Factor | Recommended | Avoid |
|---|---|---|
| When | Sow as soon as the soil can be worked in spring, and again when weather cools in late summer | Sowing after the ground is already hot |
| Seed | Whole garden seed from a packet sold for planting | Starting seedlings indoors to transplant |
| Depth | Set seed a quarter to a half inch deep. Long kinds can go a little deeper, up to about one inch | Burying seed so deep it sits under a crust |
| Spacing | Sow about one inch apart, then thin spring kinds to about two inches. Give long kinds four to six inches | Leaving a tight stand that never swells a root |
Sow garden radish while the soil is still cool. Seedlings take a frost, and an early stand lets the root swell before midsummer heat. [1] Sun and watering after the stand is up are on How to Grow Radishes.
When do I plant radishes?
As soon as the soil can be worked in spring, and again when the weather cools in late summer. Do not wait until the bed is already hot.
How to plant radishes
Sow whole garden seed directly in the bed. The root dislikes being moved, so do not start seed indoors to transplant. [2] Loosen the row at least six inches deep, and a foot or more for long kinds, so the taproot can run without hitting a stone or a hard pan. [3] Set the seed a quarter to a half inch deep and keep the surface moist until the seedlings show.
- Wait until the soil can be worked in early spring and is dry enough that it does not stick to the tools. Seedlings take a frost. [4]
- Loosen the bed at least six inches deep. For long kinds, loosen a foot or more, or use a raised bed.
- Set seed a quarter to a half inch deep, about one inch apart, in rows about 12 inches apart. Long kinds can sit a little deeper, up to about one inch.
- When seedlings show, thin spring kinds to about two inches. Thin long kinds to four to six inches. Eat the thinnings. Crowded plants stay all tops.
- Sow a short row every week or two while the weather stays cool, so you pull a few at a time instead of one woody flush. Keep the row moist until the seedlings crack the surface, then follow How to Grow Radishes.
How deep do I plant radish seed?
A quarter to a half inch for spring kinds. Long kinds can go a little deeper, up to about one inch.
What fails at planting
Seed started in a cell and yanked out for transplant often stalls, because the taproot does not like to be torn. Late sowing into hot soil is the usual reason a flower stalk rises before a usable root forms. A crust after a hard rain can stop seedlings; a light sprinkle to soften the surface helps them through. Do not drop a heavy nitrogen fertilizer in the furrow with the seed.
Can I transplant radish seedlings?
The usual crop is sown in the bed. The taproot stalls if it is torn, so do not start seed indoors to move later.
If the soil is already hot, wait until cool weather returns. Sow garden seed at a quarter to a half inch, thin so each root has room, and do not start it in a cell to transplant.
FAQ
Can I start radishes indoors?
The usual crop is sown in the bed. The taproot dislikes being moved, so a seedling yanked from a cell often stalls.
Can I plant a fall crop?
Yes. Sow again in late summer so the roots swell in cool fall weather. Long winter kinds are often sown then. A hot late-summer seedbed still makes pithy roots, so wait until the heat breaks.
Can I sow radish with carrots to mark the row?
A pinch of radish seed in a slow carrot or beet row will come up in a few days and show you the line. Pull those radishes before the slower crop needs the space. How to sow carrots stays on Planting Carrots.
Related guides
Recommended plants
References
- [1] Iowa State University Extension -
https://yardandgarden.extension.iastate.edu/how-to/growing-radishes-iowa - [2] University of Maryland Extension -
https://www.extension.umd.edu/resource/growing-radishes-home-garden - [3] University of Minnesota Extension -
https://extension.umn.edu/garden-and-home/yard-and-garden/gardening-in-minnesota/growing-radishes - [4] Cornell University Home Gardening -
http://www.gardening.cornell.edu/homegardening/scene341b.html
This note is part of Raphanus Guides.
More planting notes by plant are gathered in Planting Guides.
Updated: Reviewed by Bosquelle Editors