Radishes are one of the easiest vegetables to grow for both new and experienced gardeners. They mature very quickly, aren’t too fussy, and if you grow them in the early spring or fall, you will get some of the most delicious, crunchy harvests.
Since radishes don’t take up much space, you can easily interplant them or add a row of radishes next to your other vegetables like along the edge of a tomato bed. But if you’ve direct sown your radishes, when should you thin them out and how can you do it successfully?
Radishes should be thinned out by the time their first true leaves form. To limit any disturbance or damage to the roots of the radish sprout you want to keep, you should thin them by pinching or snipping them off at the soil level.
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Sowing Radish Seeds – Spacing and Depth
Radish seeds are typically sown 1 to 4 inches (2.5 to 10 cm) apart, about 1/4 inch (1.3 cm) deep. The spacing depends on the radish and when you plan to harvest. French Breakfast radishes, for example, can be spaced 1 to 2 inches apart.
Sow radishes by planting 2 to 4 seeds per hole. I typically plant 3 seeds. The older the seeds, the more you should sow, because older seeds have lower germination rates.
When to Thin Radishes
You can thin radishes any time up to when the first true leaves appear. True leaves are the leaves that appear after the first two seed leaves.
The reason you may want to wait until the true leaves appear is because young sprouts are vulnerable and you want to make sure the seedling you want to keep is one that will survive.
How to Thin Radishes
Never thin radishes by pulling them out. Seedlings planted next to each other can get their roots tangled, and by pulling out its neighbors, you could end up damaging the taproot of the seedling you want to keep. The taproot is the main root of the plant that will eventually develop into a mature radish.
Instead, thin out your radishes by either pinching or taking scissors and carefully snipping off the seedlings at the base of the soil. You can eat the sprouts or discard them.
The tiny roots left in the soil will eventually die as they will no longer be getting energy via photosynthesis.
How to Choose Which Radishes to Thin Out
If you’ve planted three radish seeds and have three seedlings, which two do you remove?
In most cases, it doesn’t matter, but you ultimately want to pick the healthiest seedling with the highest chance of successfully growing into a full-sized radish.
People will often keep the tallest seedling, but that one is not necessarily the best one to choose. Leggy seedlings not getting enough light may be taller but they are also weaker and may not develop a healthy, juicy root under the soil.
At the same time, you don’t want to pick a stunted sprout that won’t grow much larger.
I like to keep a radish seedling with large, full, healthy leaves that is not too leggy. Any slim, leggy radishes or super tiny stunted ones get thinned out.
To Thin or Not to Thin? Multisowing Radishes
Is it even necessary to thin radishes? According to renowned market gardener Charles Dowding, not really.
Mr. Dowding is famous for his no-dig gardening method and primarily growing in compost, but he has also championed the idea of multisowing plants, especially root vegetables like radishes.
Multisowing involves sowing multiple seeds in one planting hole and letting them grow altogether. The idea is that as they grow they will push away from each other and not really crowd each other out as we think. You can multisow beets, radishes, onions, turnips, and other root vegetables, but also leeks and onions, too.
If you decide to give multisowing radishes a whirl, space your multisown radishes at least 4 inches apart so each clump of radishes has space to grow out. You can plant 4 to 6 seeds per hole and thin out to 3 to 5 radishes per clump.