
Brassica oleracea (Gemmifera Group)
Brussels sprouts are a hardy winter brassica (cabbage family) that form sturdy, leafy stems often around 60–90cm tall. They produce edible mini-cabbage buds along the stem from autumn through winter. Thanks to their cold tolerance, sprouts remain productive into late winter, and frost actually improves their sweetness.
Step-by-step instructions for growing Brussels Sprouts
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Grow Brussels sprouts for a harvest from autumn through winter, with sprouts maturing from the bottom of the stalk upwards.
Sow seeds indoors in modules or pots around 31st March - 15th April. Use a good seed compost and cover with of soil. Keep at for germination, which takes 7-14 days.
Once seedlings have their first true leaves, prick them out into individual pots around 21st April - 28th April. Handle by the leaves to avoid stem damage and plant at the same depth as before.
Gradually acclimatise plants to outdoor conditions over 7-10 days around 12th May - 19th May. Start with a few hours in a sheltered spot and increase exposure each day.
Plant seedlings into their final position around 29th May - 12th June. Space them apart in firm, fertile soil. Firm the soil well around each plant to prevent wind-rock.
Immediately after transplanting, cover plants with fine mesh netting to protect against cabbage white butterflies and pigeons. Fit brassica collars around the base of each stem to deter cabbage root fly.
Apply a nitrogen-rich fertiliser every 28 days from 19th June until 15th September. Water it in well to support the heavy leafy growth needed for good sprout formation.
Start harvesting from the bottom of the stalk upwards around 15th September - 23rd September. Pick sprouts when they are firm and about the size of a walnut. Frost improves their flavour, so continue harvesting through winter.