Overview
What cauliflower needs, when it crops, and whether it suits your garden.
Cauliflower has a name for being tricky, and it has earned it: cold, heat, drought or a root-bound transplant can all leave you with a head the size of a coin. The fix is steady growth from sowing to cutting. Raise young plants, plant them firm, keep the water coming, and time the crop so the curd forms in cool weather.
Quick facts
- Botanical name
- Brassica oleracea (Botrytis Group)
- Soil pH
- 6.0 – 7.0
- Feeding
- Heavy feeder
- Temperature
- 16 – 21 °C
- Hardiness
- Any zone, as an annual
- Time to harvest
- 50 – 80 days
- Propagation
- Seed
Optimal growth
Growing details
- Germination
- 14 days
- Spacing
- 60 cm (24 in)
- Sowing depth
- 15 mm (⅝ in)
- Frost sensitivity
- Frost hardy
Growing calendar
- Start indoors: January, February, March, April, May, June
- Sow outdoors: April, May, June
- Transplant: March, April, May, June, July, August
- Harvest: January, February, March, April, May, June, July, August, September, October, November
Early-summer types Jan to Feb; summer and autumn types Mar to Apr; winter types May to Jun. Summer and autumn types mid to late spring; winter types late spring to early summer. About six weeks after sowing, 10 to 15 cm (4 to 6 in) tall. Early summer to autumn from summer and mini types; winter and spring from winter types, in a cool temperate climate.
Is this plant right for you?
- Cool-season crop
- Needs steady moisture
- Heavy feeder
- Needs pest netting
- Mini types for pots
- Takes space
- Spring and autumn crops
Good to know
It is a hungry plant, so feed it regularly right through the growing season. It stands frost, so it can go out earlier than tender crops.
Before You Grow
Choose a type for the season you want to harvest, and a sunny spot with deep, firm, fertile soil.
New to cauliflower? Start with a summer or mini variety: they grow faster and meet fewer problems.
What you need
Seed or young plants
Seed gives the widest choice. Bought plants should be young, stocky and not root-bound. See choose your cauliflower.
Module trays and seed compost
One seed per module means no root disturbance later. See how to raise plants.
A sunny bed with firm, fertile soil
No brassicas there for at least two years. See soil.
Fine insect mesh
On hoops, from planting day. See pests.
Twine or large rubber bands
To tie leaves over the curd. See blanching.
A sharp knife
For cutting the head with a few leaves attached.
Choose your cauliflower
Cauliflowers are grouped by when they crop. Pick the type for the season you want to eat them, then a variety.
Early-summer types are sown indoors in winter, planted out under cloches in spring, and ready in early summer. ‘Tirza’ is one.
Summer and autumn types are the most popular: sown in spring, cut from late July to October in the UK, before the first frost. ‘Nautilus’ and ‘Raleigh’ are reliable; US extensions suggest ‘Snow Crown’, ‘Amazing’ and ‘Denali’.
Winter and spring types are sown in late spring and take six months or more. They are big, hardy plants with heads up to 30 cm (1 ft) across, and take a lot of room for a long time. ‘Triomphant’ is often cut at Christmas; ‘Jerome’ copes well with cold.
Mini cauliflowers are summer types grown close together and cut at tennis-ball size, in as little as three months. They suit small plots and pots.
Coloured types have orange, purple or lime-green heads, such as ‘Sunset’, ‘Graffiti’ and the romanesco ‘Veronica’. They need no blanching.
Self-blanching varieties, such as ‘Self Blanche’, curl their own leaves over the head.
Cauliflower types compared
-
Early summer
- Sow
- Indoors, mid to late winter
- Harvest
- Early summer
- Spacing
- 45 to 60 cm (18 to 24 in)
- Notes
- Planted out under cloches in spring
-
Summer and autumn
- Sow
- Spring, indoors or out
- Harvest
- Late July to October
- Spacing
- 45 to 60 cm (18 to 24 in)
- Notes
- The most popular; cut before frost
-
Winter and spring
- Sow
- Late spring to early summer
- Harvest
- Winter to spring
- Spacing
- 70 cm (28 in)
- Notes
- Six months or more; big heads
-
Mini
- Sow
- Spring
- Harvest
- About three months from sowing
- Spacing
- 15 cm (6 in)
- Notes
- Tennis-ball heads; suits pots
-
Coloured and romanesco
- Sow
- Spring
- Harvest
- Summer to autumn
- Spacing
- As summer types
- Notes
- No blanching needed
Spacing is between plants, in UK conditions (RHS). For most gardens, a summer or autumn variety gives the surest crop.
Where cauliflower grows best
Cauliflower is a cool-season crop, and the fussiest of the cabbage family. It likes cool, damp weather.
Temperature. It grows best at 16 to 21 °C (60 to 70 °F) (Iowa State), and Utah State finds it does best below 24 °C (75 °F). Both frost and heat above about 27 °C (80 °F) slow growth and spoil the heads.
Heat. Iowa State finds days of 30 °C (86 °F) or more with nights of 25 °C (77 °F) or more can stop heads forming. Hot weather also gives loose heads with leaves growing through them.
Cold. Cauliflower is more sensitive to cold than its relatives. Illinois notes the timing is a compromise: early enough to head before summer heat, late enough to escape cold. Young plants chilled below 10 °C (50 °F) for long spells may button.
Sun. Full sun: at least six hours of direct sun a day, and UMD prefers eight to ten. Wide spacing keeps plants from shading each other and lets air through (RHS).
Where summers are hot, as in much of the eastern US, an autumn crop is usually more reliable than a spring one (UMD).
- Best growth
- 16 to 21 °C (60 to 70 °F)
- Stops heading
- Days 30 °C (86 °F), nights 25 °C (77 °F)
- Buttoning risk
- Long spells below 10 °C (50 °F)
Soil
Cauliflower needs deep, fertile soil that holds moisture but drains freely, and it must be firm.
Preparation. Dig in a couple of bucketfuls of well-rotted manure or compost per square metre, ideally the autumn before so the ground can settle. If you add it just before planting, firm the soil by shuffling across it.
pH. Iowa State gives 6 to 7; the RHS aims for about 6.5 and limes acid soil, which also helps against clubroot.
Rotation. Don’t grow cauliflower where any brassica grew in the last two years (RHS); Iowa State prefers three or four.
Planting
Raise plants in modules, move them young, and plant them deep and firm.
Plant out at about six weeks old, 10 to 15 cm (4 to 6 in) tall. Older, root-bound plants are the likeliest to button.
When to sow and plant cauliflower
Time cauliflower so its heads form in cool weather: before the heat of summer, or after it.
In the UK, the main sowing season is March to May. Sow early-summer types indoors in January or February, and winter types from late spring to early summer (RHS).
Spring crop in a warm-summer climate. Sow indoors four to seven weeks before planting out. Plant out two to three weeks before the average last frost (Illinois, Utah State); UMD allows three to four. Planted too early, plants may button.
Autumn crop. Plant out in early to late July, raised from a sowing four to five weeks earlier (Iowa State, Illinois). It heads in cool autumn weather, and in warm-summer climates it is often the more reliable crop (UMD).
Avoid gluts. A row sown on the same day tends to mature together. Sow small batches a few weeks apart instead.
- UK: sow mainly March to May.
- Spring crop: plant out 2 to 3 weeks before the last frost.
- Autumn crop: plant out in July.
How to raise cauliflower plants
Raising plants in modules gives the most reliable results: you control the temperature, slugs can’t reach them, and they move without a check.
-
Sow one seed per module
In peat-free seed compost, about 1.5 cm (⅝ in) deep, into damp compost.
-
Keep them warm and bright
At 12 to 22 °C (54 to 72 °F). Seeds germinate in about two weeks. Keep the light good and water regularly.
-
Thin to one
Remove the weaker seedling in each module.
-
Or sow outdoors
From mid to late spring, 1.5 cm (⅝ in) deep in a seedbed, 10 to 15 cm (4 to 6 in) apart, to lift and replant later.
-
Don’t let them stall
Illinois warns never to hold plants in trays after they are ready: they harden, stop growing, and rarely head well.
-
Move them at about six weeks
When they are 10 to 15 cm (4 to 6 in) tall with four to six true leaves and roots filling the module.
How to plant cauliflower
Deep, firm planting with as little root disturbance as possible.
-
Harden off indoor-raised plants
Over several days, starting in a shaded, sheltered spot and giving a little more sun each day.
-
Water before moving them
Then lift or unplug each plant gently, keeping the rootball whole.
-
Plant deeper than before
With the lowest leaves at the soil surface, so they root deep and firm.
-
Give them room
Summer and autumn types 45 to 60 cm (18 to 24 in) apart in rows 60 cm (24 in) apart; winter types 70 cm (28 in) each way; minis 15 cm (6 in) each way.
-
Firm in and water well
Press the soil firmly round each plant, then soak it.
-
Cover straight away
With fine insect mesh on hoops, against pigeons, caterpillars and root fly. In early spring, fleece or cloches also keep off frost.
Care
Even moisture, a nitrogen boost, mesh against pests, and leaves folded over the curd to keep it white.
The one rule: no check in growth. Dry soil, cold snaps and hungry roots all show in the head.
Care by growth stage
Young plants
Protect: mesh, slugs, spring frost · Water: regularly
Water until they root deeply, weed, and keep them covered. See watering.
Growing on
Feed: 3 to 4 weeks after planting · Mulch: 5 to 8 cm (2 to 3 in)
Feed and mulch; keep growth steady. See feeding.
Curd forming
Water: most critical now · Blanch: tie leaves over
Keep moisture even and cover the curd at 5 cm (2 in). See blanching.
Ready to cut
Harvest: about a week after tying
Check every day or two once tied. See harvesting.
End of season
Rotate: no brassicas for 2 years
Pull and compost plants, clearing debris that harbours pests and disease.
Watering cauliflower
Cauliflower needs soil that is damp at all times but never waterlogged. Dry soil can stop growth and spoil the head.
How much. About 2.5 cm (1 in) a week, rain included (Iowa State); Utah State, in a dry climate, gives 2.5 to 5 cm (1 to 2 in). Water deeply and keep the moisture even.
When it matters most. Young plants until they have rooted deeply, and again as the curds form, so they reach a good size.
How. At the base, ideally with a soaker hose or drip line, to keep leaves dry. Collected rainwater is fine.
Mulch with compost, straw or shredded leaves to hold moisture and smother weeds, leaving a small gap around the stems. Utah State lays organic mulch once it gets hot, to keep the roots cool.
Feeding cauliflower
Cauliflower has a high nutrient requirement, and hunger is one of the stresses that cause buttoning.
Before planting, dig in compost or manure. Without a soil test, Iowa State works in a general fertiliser, such as 10-10-10, at 0.5 to 1 kg per 10 m² (1 to 2 lb per 100 sq ft).
At planting, UMD uses a starter feed.
Three to four weeks later, side-dress with nitrogen along the row, about 15 cm (6 in) from the plants, and water it in (Utah State, Iowa State). Illinois feeds when plants are half grown.
In the UK, the RHS finds feeding isn’t usually needed on good soil; on poor soil, give an organic, nitrogen-rich feed before heads start to form.
Blanching and protecting the curd
Cauliflower needs no pruning. What it needs is shade over the curd: sun turns white heads yellow or purple and can spoil the flavour.
When. When the curd is about 5 cm (2 in) across, the size of a tennis ball (Iowa State, UMD).
How. Pull three or four large outer leaves up over the head and tie them loosely with twine, cloth strips or a large rubber band. Or snap a leaf over the curd and tuck it in on the far side.
Then check often. The head grows fast after tying and is usually ready 7 to 12 days later (Illinois); UMD gives 4 to 8 days, longer in autumn. In warm weather, look every day or two.
In winter, tie the leaves over the curd to protect it from hard frost, with fleece over the top for extra cover (RHS).
Coloured varieties don’t need blanching, and self-blanching ones cover their heads themselves.
- Cover the curd at about 5 cm (2 in) across.
- Tie loosely, leaving room to grow.
- Ready about a week later: check often.
Cauliflower in containers
Full-size cauliflowers are too big and too thirsty for most pots, but mini cauliflowers grow well in them.
Pot. Large and deep: the RHS plants up to four minis in a 40 cm (16 in) diameter container of peat-free multi-purpose compost.
Planting. Set them deep, with the lowest leaves at the compost surface, and water well.
Care. Stand the pot in a bright, sheltered spot and water whenever the compost starts to dry. Net it like any brassica.
Problems
Most failures are growing problems: buttoning, loose heads in heat, and discoloured curds.
Common cauliflower problems
Most cauliflower failures are growing problems, and most come down to a check in growth.
Tiny heads soon after planting
- Buttoning
- Stress
Buttoning: the head stops at 2.5 cm (1 in) or less. Causes are long cold spells below 10 °C (50 °F), dry or poor soil, loose soil, and planting out old, root-bound transplants. Plant young and keep growth steady.
No head at all, or a loose one in summer
- Heat
Hot days and warm nights stop heading. Plant earlier in spring, or grow an autumn crop.
Leaves growing through the head
- Heat
The curd matured in hot weather, which also makes it separate into loose, small clusters (Illinois). Time the crop to head in cool weather.
Yellow or purple-tinged curd
- Sun
- Blanching
Sun on the curd. Tie leaves over it when it is 5 cm (2 in) across. See blanching.
Grainy, ‘ricey’ curd
- Overmature
The head was left too long and its buds began to open. Cut while it is still firm and smooth.
Brown spots on the head, hollow stem
- Boron
- Nutrients
A nutrient deficiency (Utah State). A soil test tells you whether your soil is short.
More problems with cauliflower
Common pests
Cabbage caterpillars
Cabbage white butterflies and moths lay eggs whose green caterpillars eat holes in leaves and hide in the heads. Net the crop, pick them off, or treat young caterpillars with Bacillus thuringiensis (Bt).
Pigeons
Tear the leaves, often leaving only stalks and veins. Keep plants under mesh or netting.
Cabbage root fly
Maggots eat the roots and young plants wilt. Mesh from planting day keeps the flies off (RHS).
Flea beetles
Tiny, shiny black beetles that jump and pepper seedlings with small round holes. Minor damage doesn’t matter; mesh keeps them off young plants.
Aphids
Mealy cabbage aphids form grey colonies under leaves, which crinkle and curl. Knock them off with a strong jet of water or use insecticidal soap.
Cabbage whitefly
Small white insects under the leaves that fly up when disturbed. Often not a serious problem.
Slugs and snails
Eat young plants, especially in damp weather. Weeds give them cover: keep the bed clean.
Common diseases
Clubroot
A soil-borne disease that swells and distorts roots and stunts plants, and lasts in soil for many years. Improve drainage, lime acid soil, and rotate.
Downy mildew
Brought on by wet weather. Raised beds and anything that improves soil and air drainage help (Illinois).
Leaf spot
Black, sooty spots in rings on leaves and heads. Avoid overhead watering, clear debris and rotate (Utah State).
White blister
White pustules on the leaves that reduce vigour (RHS).
Harvest & Use
Cut the head while it is firm and tight, with a few leaves to protect it.
Harvesting cauliflower
Cut as soon as the head is a good size and still firm and compact. Don’t wait: once it starts to separate, it is past its best and tastes bitter.
When. Three to six months from sowing, depending on type and weather (RHS). A well-grown head is 15 to 20 cm (6 to 8 in) across (Illinois); minis are cut at tennis-ball size.
Signs it’s ready. A compact, firm, fairly smooth curd, white in white varieties, before it yellows or loosens.
How. Cut the stem below the head with a sharp knife, keeping a ruff of leaves round it to protect the curd and help it keep.
A row ready at once? Start cutting some heads a little small, rather than losing the last ones to overmaturity.
- Cut while the head is firm and tight.
- Keep a few leaves round it.
- Start early if a whole row is ready together.
Storing and using cauliflower
Cauliflower is best eaten fresh, but keeps well if it stays cold.
In the fridge. The RHS keeps it several days, better with a few leaves left on; Iowa State stores it up to 2 to 4 weeks in a perforated bag. UMD gives 2 to 4 weeks at near freezing and very high humidity.
Freezing. Blanch florets in boiling water, cool quickly, drain, and freeze.
Cooking. Roast, steam, or use in soups, curries and cauliflower cheese. Grate it into ‘cauliflower rice’, or eat the florets raw. Purple heads turn green when cooked.
More to Explore
Quick answers, guides that pair well with cauliflower, and the sources behind this one.
Frequently asked questions
Why is my cauliflower head so small?
Usually buttoning, from a check in growth: cold, drought, poor or loose soil, or old transplants. See common problems.
Why is my cauliflower turning yellow?
Sun on the curd. Tie the leaves over it when it is about 5 cm (2 in) across. See blanching.
Do I have to blanch cauliflower?
Only white varieties, and not self-blanching ones. Unblanched heads are cream or yellowish, and can taste stronger.
Why is my cauliflower loose and separating?
It headed in hot weather, or was left too long. Time crops for cool weather and cut promptly.
When should I plant cauliflower?
It depends on type and climate: in the UK, sow mainly March to May; in warm-summer US climates, plant out two to three weeks before the last frost, or in July for autumn. See when to sow and plant.
How far apart should cauliflower be?
It depends on type, from 15 cm (6 in) for minis to 70 cm (28 in) for winter types. See how to plant.
Can I grow cauliflower in a pot?
Mini varieties, yes: up to four in a 40 cm (16 in) pot. See containers.
Does cauliflower grow back after cutting?
Not usefully. Unlike broccoli, it makes one head; pull the plant after cutting.
Is purple cauliflower grown the same way?
Yes, and it needs no blanching. The colour turns green when cooked.
Related guides
Sources
- How to grow cauliflowers (opens in a new tab) Royal Horticultural Society
- Growing cauliflower in the home garden (opens in a new tab) Iowa State University Extension and Outreach
- Growing cauliflower in a home garden (opens in a new tab) University of Maryland Extension
- Cauliflower (opens in a new tab) University of Illinois Extension
- Cauliflower in the garden (opens in a new tab) Utah State University Extension