Radish

Radish is an annual, so there is nothing to overwinter: you simply sow again in spring (from March, earlier under fleece). Late autumn crops can be covered with fleece in frost so that they can still ripen.

You propagate radishes exclusively by direct sowing. Sow the seeds from March (cold frame/greenhouse from early March, outdoors from late March) to early September, about 3 to 5 cm apart in rows, with 10 to 15 cm between rows. The sowing depth is 0.5 to 1 cm; seeds sown deeper germinate worse and often form long, misshapen roots. At around 12 to 15 °C the seeds germinate within about a week, and after 3 to 4 weeks the first roots are ready to harvest. Keep the soil evenly moist to avoid split roots. For a harvest throughout the season, sow a new row every 1 to 2 weeks (succession sowing). In high summer choose a lightly shaded spot, as radishes bolt quickly in great heat.

If you want to save your own seed, note: use only open-pollinated (non-hybrid, not “F1”) varieties. The next generation of hybrids does not come true to variety. Radishes are also self-incompatible cross-pollinators, pollinated by insects, and they cross easily with other radish varieties and even with winter radish (same species). So let only a single variety flower per season or isolate the varieties in space or time, otherwise the harvested seed is no longer true to variety. Let at least 15 to 20 strong plants go to flower (a broad base of plants preserves variety diversity). From mid/late May the plants become woody and form flowers, after which green pods develop. When the pods turn brown to greyish but the plant is still vigorous, harvest them and let them dry further in a dry place for 2 to 3 weeks before you take out the seeds and store them cool and dry. Tip: wrap ripening pods in organza bags so that you do not lose seeds when pods burst.