Cauliflower
Brassica oleracea var. botrytis
Cauliflower is widely considered the most challenging brassica to grow well. It demands consistent moisture, rich soil, and an uninterrupted growing period — any stress (drought, cold snaps, root disturbance) can cause the plant to produce tiny, premature 'button' heads or bolt to seed. Despite this, the satisfaction of growing a perfect white curd makes the effort worthwhile. Start seeds under cover and transplant carefully when seedlings are sturdy but not root-bound. Water consistently and feed with a nitrogen-rich fertiliser. As the curd develops, snap a few outer leaves over it to protect it from sun yellowing (called 'blanching'). 'Autumn Giant' and 'Snowball' are reliable UK varieties. Mini cauliflowers, spaced at just 15cm, produce tennis-ball-sized heads and are more forgiving for beginners.
Plan where to grow Cauliflower using our vegetable garden planner.
When to Sow Cauliflower
Sow cauliflower in February, March, April, May, August.
Time to Harvest Cauliflower
Expect to harvest approximately 3 months after sowing, usually from June to November.
Companion Plants for Cauliflower
- Broad Beans
Beans fix nitrogen, and leafy brassicas such as cauliflower benefit when they follow or grow near legumes.
- Celery
Celery is traditionally grown with brassicas in the belief its scent deters cabbage white butterflies, though the evidence is anecdotal.
- Runner Bean
Runner beans leave nitrogen in the soil, and cauliflower is a heavy feeder that benefits from it, whether grown alongside or in the same bed the following year.
- French Bean
Beans add nitrogen to the soil as their roots break down, which suits leafy, hungry brassicas such as cauliflower.
Expected Yield
One head per plant, typically 400g–1kg. Mini cauliflowers produce 200–300g heads.
Common Problems with Cauliflower
Buttoning (tiny, premature curds)
Cauliflower produces small, button-sized curds when the plant is stressed — typically by drought, cold snaps, transplant shock, or root disturbance. Ensure consistent moisture throughout the growing season, transplant carefully without disturbing roots, and avoid checking growth by letting seedlings become root-bound in modules. Rich, fertile soil and steady conditions are essential.
Caterpillars
Cabbage white butterfly caterpillars can devastate cauliflower leaves, reducing the plant's ability to form a decent curd. Cover with fine mesh netting immediately after transplanting and keep it secure throughout the growing season. Hand-picking eggs (yellow clusters on leaf undersides) and caterpillars is effective on a small scale — check every few days from May onwards.
Discoloured curds
Cauliflower curds turn yellow or brownish when exposed to direct sunlight. As soon as the curd reaches 5cm across, snap a few of the large inner leaves over the top to shade it — a technique called 'blanching'. Check regularly and harvest promptly once the curd is tight and white, before the florets start to separate and the surface becomes grainy.
Cauliflower: common questions
When should I sow cauliflower in the UK?
Sow cauliflower in February–May and August. Sow under cover (a greenhouse, windowsill or heated propagator) and plant out once the weather has warmed.
How far apart should I plant cauliflower?
Space cauliflower about 60cm apart. It grows to around 60cm tall. Sow seeds 1–2cm deep.
How long does cauliflower take to germinate?
Cauliflower seeds usually germinate in 5–10 days, depending on temperature.
When is cauliflower ready to harvest?
In the UK, cauliflower is usually harvested from June to November. It's ready about 3 months after sowing.
Does cauliflower come back every year?
No. Cauliflower is a biennial that's grown for a single season: it's harvested in its first year, before it would flower, so sow it fresh each year.
What grows well with cauliflower?
Good companions for cauliflower include Broad Beans, Celery, Runner Bean and French Bean. See the companion plants section above for why each one helps.
Is cauliflower frost hardy?
Only partly. Cauliflower is half-hardy: it copes with cold but not frost, so plant it out after the last frost (usually mid to late May) and protect it if frost is forecast.
Is cauliflower a brassica?
Yes. Cauliflower belongs in the brassicas group for crop rotation. Grow it in a different bed each year, alongside other brassicas, so pests and diseases don't build up in the soil.
Cauliflower guides
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