Sow in modules under cover from February and plant outdoors at final spacing after hardening off. Direct sow from the end of February until August in rows 30 cm apart. Thin seedlings to 30 cm once large enough. Protect from frost with fleece if sowing early. Young plants and baby kohlrabi are edible.
Prepare the area by removing weeds and incorporating plenty of organic matter to the soil before planting. Transplant your seedlings into their final growing position around May when the risk of frost has passed. You can plant earlier, but they will need fleece.
Keep well-watered; hot weather and dry conditions will encourage bolting. Early and late sowings can help avoid this issue, especially in the midsummer heat. Mulch to retain water and prevent weed growth.
Kohlrabi may attract pests such as slugs, snails, and aphids. Water in the mornings to avoid wet soil at night that will encourage slug munchies. Hot and dry conditions can induce bolting and affect the quality of the bulb. Water adequately and choose appropriate planting times to avoid this. Provide protective covers such as fleece for frost and mesh to prevent pigeon and butterfly damage.
Harvest time varies; generally, baby kohlrabi (golf ball size) is ready from around 6 weeks, mature plants (tennis ball size) with a slightly firmer texture at around 12 weeks. Harvest the whole plant, including edible leaves. Thinning out some young tasty baby plants makes room for larger plants to grow.
Great eaten cooked or raw, its crisp crunch and peppery taste make it perfect for roasting, stir-fries, salads, Asian slaw, and spring rolls. Peel to remove the outer skin, then spiralize and stir fry with ginger and miso dressing; delicious.
Kohlrabi belongs to the species brassica oleracea. To prevent cross-pollination, isolate or ensure no other brassicas of this species are flowering at the same time within 0.5 miles. Best grown in a block of at least twelve plants. Select true-to-type, healthy plants with traits you desire in your future crops, particularly avoiding early bolters. Kohlrabi is a biennial, and produces a flower stalk in the second year after a period of cold. Bees and other pollinators will assist with the pollination process. When the seed pods start turning brown and the seeds inside them black, they are ready to harvest. Cut the whole plant and dry further on a sheet indoors, as once ripe, the seeds shatter easily. Stomp or stand on the plants to break up the seed heads, then sieve out the debris. Store the cleaned and dried seeds in a cool, dry place.