Sowing radishes: spacing and successive crops
Learn how salad and winter radishes differ in sowing depth, spacing and harvest, then stagger small batches for a steadier supply.
By Marmanda3 min read
For UK salad radishes, sow in spring or late summer, avoid hot, dry spells and pick the roots as they reach a useful size. The RHS recommends sowing winter radishes in July or August; they need more room than salad types. Check the packet before preparing the row: depth and spacing depend on which type you are growing.
Which radish type belongs in this row?
Salad radishes are grown for small roots and can be sown in spring and again in late summer in the UK. Winter types need a longer season and different spacing. The RHS guide treats them as separate crops, so do not transfer a small salad radish method to a larger winter root.
The French SNHF sheet further separates radishes for forcing, all-season types, summer and autumn radishes, and winter radishes. Its windows describe French conditions. They are a useful comparison, but the UK timing below follows RHS guidance and should still be adjusted to your local site and variety.
How deep and far apart should seed be?
For small salad radishes, the RHS recommends a drill about 1 cm deep, seeds 2.5–5 cm apart and rows 15 cm apart. Cover lightly and water with a fine rose if the surface is dry. A hard stream may move the shallow seed; aim for even moisture without leaving the bed waterlogged. Mark the row so emerging seedlings are easy to find.
In the RHS winter-radish method, sow in July or August about 2 cm deep, then space seeds—or thin seedlings—to 15–20 cm apart depending on variety, with rows 15 cm apart. Keep this separate from salad radish spacing. Thin once seedlings are visible enough to handle without disturbing the plants you keep.
How can you stagger small sowings?
Start with a short row rather than the whole packet. Once it has emerged, decide whether conditions still suit another sowing. This spreads the work and helps you learn how the variety develops in your bed. There is no need to force a succession through hot, dry weather simply to follow a calendar.
The RHS lists germination at seven to ten days and says some salad radishes may be ready from four weeks in its UK guidance. The SNHF gives four to six weeks for its all-season radishes and about two weeks longer for radishes it calls radis raves—large, long roots—and summer or autumn types. These are source-specific estimates; variety, temperature and moisture affect the result. Check a sample root before lifting the full row.
When should roots be picked?
Harvest progressively rather than waiting for every plant to reach one size. The SNHF warns that radishes left too long can become hollow. Regular picking also lets you spot a row that has dried out or grown unevenly. If roots remain small, check the variety, spacing and soil moisture before changing the whole bed.
When the first roots are ready, loosen the soil beside them if it is firm and lift a few at a time. This leaves the remaining plants in place and gives you a direct check on size and texture. Clear weeds while small so you can see the row, and avoid hoeing close enough to damage roots. If growth stalls during a dry spell, restore moisture gently and reassess before sowing another batch; a second sowing will not correct a problem in the first row.
Record the type, sowing date and conditions to compare batches. The vegetable sowing and planting calendar gives wider seasonal context, while the small-garden guide can help you reserve a row of manageable length.