When and how to sow your seeds
Sow kale from March until August undercover in module trays, transplanting into its final growing position after about 4-6 weeks. From May onwards, kale can also be sown directly outside in drills 50cm apart once the soil has started to warm up.
Different varieties are suited to different seasons, so check the information on your seed packets to ensure you are sowing them at the correct time of year.
Plant out into final growing position at 50x50cm spacing. Kale plants do not like loose soil, so make sure to bury seedlings right up to their first true leaves and firm in the soil around the plants well.
Protect seedlings with horticultural fleece if planting out before the last frost.
Kale prefers well-draining and fertile soil so be sure to amend your soil with good quality compost or well-rotted manure before planting. You can also use mulch around the base of plants to hold in soil moisture and inhibit weed growth.
Pests and Diseases
Horticultural mesh can be used to protect young seedlings from the larvae of cabbage root fly or the caterpillars of cabbage white butterflies. However, once the eggs are laid it can also trap them inside and cause further problems. Keep an eye on your plants to avoid any crop loss. Often opening up the mesh to allow birds to predate the caterpillars or larvae can help to restore the balance.
Birds themselves can also become a problem in the winter months and horticultural mesh can be used to protect your crops.
The risk of club root can be reduced by making sure you follow a rotation in your garden beds and leave sufficient time in between brassica crops.
Risks of fungal disease can also be reduced by spacing out plants correctly and making sure to remove dead or decaying leaves from around the base of the plants.
Depending on the variety, kale can either be harvested as a cut and come again crop by removing the bottom leaves or cut as tender, young leaves for salads.
Winter hardy varieties of kale stand up well to cold temperatures and can be harvested throughout the winter months. Side-shoots may form in February or March after the main crown has been harvested and are delicious alternatives to sprouting broccoli.
Kale belongs to the species Brassica oleracea and will cross with all other plants within it. If you want to save seed from kale, make sure that no other brassicas of this species are allowed to flower. Kale for seed is best grown in a block of at least twelve plants – make sure to choose plants that are true to type, are healthy and have shown disease resistance.
Allow plants to flower and then begin to dry, then cut the whole plant and mature further on a sheet indoors. When fully dry the seeds will fall out of the heads very easily. You can stand on the plants to break up the seed heads and then sieve out the debris.