Cauliflower Brassica oleracea var. botrytis
Reviewed June 2026 · how we check this
A cool-season brassica grown for its dense white head, or curd, of undeveloped flower buds. Famously fussy — it demands steady cool weather, rich soil, and constant moisture — but a well-grown, blanched head is the prize of the cool-season vegetable garden.
Light
Cauliflower needs full sun — at least six, ideally eight, hours of direct light a day to fuel the leafy growth that powers a big, dense head. Skimp on light and you get loose, undersized curds on lanky plants. The catch is timing: this is a cool-season crop, so you want full sun paired with cool air, which means growing in spring before summer heat lands or in late summer for a fall harvest. In warm regions and the lengthening days of late spring, a little afternoon shade can buy you cooler leaf temperatures and stall the bolting that ruins a crop, but never grow cauliflower in genuine shade.Watering
Cauliflower is thirsty and unforgiving of drought — any check in growth from dry soil can trigger a premature, ricey or 'buttoned' head that never sizes up. Give it a consistent 1 to 1.5 inches of water per week, more in heat or fast-draining soil, aiming to keep the root zone evenly moist but never waterlogged. Deep, regular soakings beat frequent sprinkles; water at the base to keep the foliage dry and discourage disease. A 2–3 inch mulch of straw or compost holds moisture, smooths out the wet-dry swings this crop hates, and keeps the soil cool as the season warms.Soil & potting
Cauliflower demands rich, fertile, firm soil with a near-neutral pH of 6.5–7.0. Work in several inches of compost or well-rotted manure before planting to supply the steady nitrogen heavy feeders need. Unusually, the soil should also be firm, not fluffy — loose ground produces loose heads, so tread the bed lightly or let it settle before transplanting. Good drainage is essential, but the soil must still hold moisture between waterings; sandy beds need extra organic matter. A low-pH soil also raises the risk of clubroot, so lime acidic ground the season before if a test calls for it.Humidity & temperature
This is a temperature-driven crop above all. Cauliflower thrives in steady, cool conditions around 60–70°F and grows best where days and nights stay mild for the eight-to-twelve weeks it takes to head up. Sustained heat above the mid-70s, or a hard cold snap below freezing, stresses plants into bolting, buttoning, or producing bitter, loose curds. Young transplants exposed to prolonged cold below about 50°F can button as well, so harden off carefully and time plantings to dodge both heat and frost. Mature plants tolerate light frost, and a touch of cold can even sweeten the curd, but the window for trouble-free growing is genuinely narrow — which is exactly why cauliflower has its reputation.Fertilizing
As a heavy feeder, cauliflower wants steady nitrogen to build the large leaf canopy that ultimately makes a large head. Mix a balanced or nitrogen-leaning fertilizer into the bed at planting, then side-dress with compost or a nitrogen source about three weeks after transplanting and again as the plants approach heading. Watch for cupped, scorched leaf margins, a sign of boron deficiency common in brassicas, and for purpling that points to a need for steadier feeding or warmer soil. Ease off heavy nitrogen once the curd begins to form so the plant channels energy into a tight head rather than more leaves.Pruning & maintenance
There's little pruning, but blanching is the signature task for white varieties: once the curd reaches egg-size, gather the plant's own outer leaves up over it and tie them loosely with twine or a soft tie to shade the head from sun. Blanching keeps the curd creamy white instead of yellowed and coarse; self-blanching and colored types can skip it. Harvest is the real event — cut the head with a few inches of stem and some wrapper leaves once it is full, firm, and dense but before the buds begin to separate and 'rice.' A loose, spreading head means you waited too long.Propagation
Cauliflower is grown from seed, almost always started indoors for transplanting since precise timing matters so much. Sow seeds a quarter-inch deep in cells or trays about 4–6 weeks before your target transplant date, keeping them at 60–70°F with bright light so seedlings stay stocky rather than leggy. Harden off over a week, then set transplants out 18–24 inches apart in rows about 30 inches apart, after the worst frost for spring crops or in mid-to-late summer for fall ones. Direct sowing works only where the cool season is long; in most gardens transplants give you the head start this slow, demanding crop needs.Common problems
Through the year
Spring
Start seeds indoors 4–6 weeks before transplanting; harden off and set out hardened plants after hard frost passes, racing to head up before summer heat.
Summer
Tough season — keep spring crops cool, mulched, and well-watered, and start seeds indoors mid-to-late summer for a fall planting once heat eases.
Fall
Prime cauliflower weather. Transplant fall starts, blanch white heads as curds form, and harvest into the cool, even temperatures this crop loves.
Winter
Mostly off-season; in mild zones overwinter hardy types under frost cloth, and elsewhere plan next year's varieties and amend beds with compost.
Companion planting
Pairs well with beets, onions, garlic, celery, and aromatic herbs like dill and chamomile that draw beneficial insects; avoid crowding it near other heavy-feeding brassicas, and keep strawberries and pole beans at a distance.
Recommended supplies for Cauliflower
- A seed-starting kit
- Frost cloth for cold snaps
- A raised garden bed kit
- Neem oil for pests
- A balanced liquid fertilizer
Affiliate links — we may earn a small commission at no cost to you.
You might also like
Go deeper
The complete Vegetable Gardening care library
Every species in one printable, organized reference — side-by-side care, a pet-toxicity table, and a seasonal calendar.