Brassica
How to grow cauliflower
Brassica oleracea (Botrytis group)
Cauliflower is the hardest brassica to grow well, because the plant must never stop growing between sowing and cutting. Choose the type for the season: sow summer varieties under glass in January or February, autumn ones in April or May, and overwintering ones in May for heads the following spring. Plant into rich, firm, moist soil at pH 6.5 or above, water through every dry spell and feed generously. A plant that is checked makes a head the size of a golf ball.
- Hardiness
- Hardy; winter types fully hardy
- Position
- Full sun
- Soil
- Very rich, firm, moisture-retentive
- Ideal pH
- 6.5 to 7.5
- Water
- High, any dry check makes curds button
- Feeding
- Heavy feeder
Sowing and planting cauliflower
WhenSow Jan to May by type; transplant 6 weeks later; harvest Jun to Nov (overwintered types Mar to May)
Starting off
Sow 1 to 2 cm deep in modules at 15 to 20 °C, germinating in 7 to 12 days: January to February under glass for early summer, April to May outdoors for autumn, May for overwintering types. Transplant at 6 weeks with 4 to 5 leaves, watering well before and after, and never let seedlings sit pot-bound, which causes buttoning.
Spacing and planting
Summer and autumn types 60 cm apart in rows 60 cm apart; winter and spring-heading types 70 to 75 cm each way; mini-cauliflowers 15 cm each way for single-portion curds. Plant deep and firm hard. Only mini types suit a container, and then a 30 cm pot each.
Varieties worth growing
- All The Year Round
- The forgiving standard: sown in succession it heads through summer and autumn. Start here if you have not grown cauliflower before.
- Snowball
- Compact early summer type with tight white heads from a January or February sowing; suits closer spacing in small beds.
- Clapton F1
- Resistant to clubroot, with large white curds in late summer and autumn. The answer on infected allotment soil.
- Graffiti F1
- Deep purple curds that need no blanching and keep most of their colour when steamed. Summer to autumn.
- Aalsmeer
- Overwintering type: planted in July, stands the winter and heads in April, when little else is ready.
Cauliflower month by month
Timings are for central England. Allow two weeks later in the north and on cold, heavy soil.
- January
Sow early summer varieties under glass at 15 °C. Check netting on overwintering plants.
- February
Sow summer varieties under glass. Give overwintering plants a nitrogen top-dress late in the month.
- March
Harden off and plant January sowings under fleece. Sow more summer varieties. Cut the first spring heads.
- April
Sow autumn varieties. Plant out February sowings with collars. Cut spring heads.
- May
Sow winter and overwintering varieties. Plant out, water in well. Last spring heads; clear the stumps.
- June
Plant autumn varieties. First nitrogen top-dress three weeks after planting. Cut early summer heads.
- July
Plant winter and overwintering varieties. Water twice a week in dry weather. Fold leaves over swelling curds.
- August
Cut summer heads. Keep watering. Last nitrogen for plants that will stand the winter.
- September
Cut autumn heads while tight. Check the mesh for gaps.
- October
Cut autumn heads. Swap insect mesh for pigeon netting on plants staying in the ground.
- November
Last autumn heads; fold leaves over them against frost. Firm in any overwintering plants rocked by wind.
- December
Nothing to do except check the netting.
Feeding cauliflower
One of the hungriest crops in the vegetable garden. Feed the bed well before planting and keep nitrogen coming while the leaves are being made, because the size of the plant when it starts to head sets the size of the curd.
One of the hungriest brassicas, steady nitrogen and unbroken growth, or the curds 'button' prematurely.
Feeding plan
The winter before planting, only if a test shows pH below 6.5
Garden Lime (calcium carbonate)
About 0.5 kg/m², at least a month apart from manure. Acid soil also locks up the molybdenum that cauliflower needs.
One to two weeks before transplanting
Fruit & Vegetable Fertiliser 4-5-6
100 g/m² raked into the firmed surface. At 60 cm each way a plant has 0.36 m², so that is 36 g per plant.
Three weeks after transplanting, and once more 5 to 6 weeks later
Organic Nitrogen Fertiliser 13% N
40 to 55 g/m², the label rate for the hungriest brassicas: 14 to 20 g per plant, roughly half a rounded handful, scattered round the plant and watered in. Fast summer types are cut before the second dose is due.
Late February, overwintering types only
Organic Nitrogen Fertiliser 13% N
40 g/m², about 14 g per plant, as growth restarts. Give these plants no nitrogen between the end of August and February, so they go into winter hard.
Before planting, only where earlier curds were brown inside or stems were hollow
1 to 2 g/m², a quarter to half a level teaspoon per square metre, scattered evenly, once a season and never exceeded.
Signs to watch
Thin, strappy leaves with no blade and a blind centre
Molybdenum short on acid soil (whiptail)
Lime to pH 7 and apply sodium molybdate
Brown, bitter curds and hollow stems
Boron short
Seaweed or a light borax dressing
Tiny, premature curds (buttoning)
A check from drought, cold or pot-bound seedlings
Keep growth unbroken
Pests, diseases and problems
Transplants wilt, turn blue-grey and stop growing; roots eaten away by white maggots
Cabbage root fly. Even plants that survive are checked, and a checked cauliflower buttons
Brassica collars fitted flat round the stem at planting, or fine insect mesh over the whole bed from day one.
Holes in leaves and caterpillars with their droppings lodged in the curd
Cabbage white butterflies and cabbage moth, June to October
Fine mesh on hoops, clear of the leaves, for the whole summer. Soak a cut head in salted water for ten minutes to float out any that got through.
Leaves stripped to the ribs, especially on overwintering plants
Woodpigeons
Net on a frame from planting; keep it on overwintering types until the heads are cut.
Plants wilt on warm days and stay small; roots swollen and distorted
Clubroot
Lime to pH 7 or slightly above, improve drainage, raise plants in 9 to 12 cm pots of clean compost, and grow Clapton.
Seedling leaves peppered with small round holes in April and May
Flea beetle
Raise seedlings in modules under cover, plant out only when sturdy, keep them watered and cover with fine mesh.
Grey, mealy insects in dense colonies under the leaves and in the heart
Mealy cabbage aphid
Squash colonies early, wash off with a strong jet of water, and clear old brassica stumps by April.
White curd turns yellow in summer, or brown and soft after a frost
Sun or frost reaching the exposed curd
Snap two or three of the inner leaves over the curd as soon as it is the size of an egg.
Harvest and rotation
Harvest and storage
Cut in the morning while the curd is tight and white, before the florets separate, 16 to 20 weeks from sowing for summer types, 40 to 50 weeks for overwintered ones. Cut with a knife, keeping a frame of inner leaves around the curd. One curd of 0.5 to 1.5 kg per plant. Hang upside down in a cool shed for 3 weeks, or freeze florets.
Rotation and companions
Rotation: brassica group, 4-year gap, planted after peas or broad beans on limed, settled ground. Celery and dwarf beans alongside suit the same rich, moist regime.
Good to knowAny check ruins the curd, so never let it dry out; bend a few leaves over the curd to keep it white.
Growing cauliflower in pots
Full-sized cauliflowers are a poor use of a pot: each needs a 40 to 50 litre container, daily watering and three to four months to produce one head. Mini cauliflowers are the exception. Sow a summer variety such as Snowball or All The Year Round, grow one plant in a 30 cm pot (about 15 litres) of peat-free compost with 5 g per litre of the 4-5-6 mixed in, which is 75 g, and expect a single-portion curd 8 to 10 cm across. The compost must never dry out, so stand the pot in a saucer in hot weather and water morning and evening if needed. A dry day in a pot does the same damage as a dry fortnight in the ground.
Cauliflower: common questions
Why is my cauliflower not forming a head?
The plant has been checked at some point, or it is a winter type that is not due to head yet. Drought, cold, root fly damage or seedlings left too long in their modules all cause tiny, premature heads or none. Overwintering varieties planted in July will not head until the following March to May, however large they grow.
How long does cauliflower take to grow?
Summer types take 16 to 20 weeks from sowing to cutting, and autumn types up to six months. Overwintering types take 40 to 50 weeks, because they stand through winter and head in spring. The variety decides the timing, so check the packet and sow by type.
Why has my cauliflower gone purple or yellow?
Light on the curd causes both. Sun turns white curds yellow or flushes them purple, and cold nights deepen the purple. The head is safe to eat and tastes the same. To keep curds white, snap inner leaves over them once they reach egg size.
Sources
Growing information on this page was checked against these references in November 2026. Feeding rates are Dr Forest label rates.