Start seeds indoors
Sow 0.25 inches deep and keep the mix evenly moist; do not let the surface crust or dry out before sprouts emerge. Seedlings emerge in 5–10 days in warm soil.
A cool-season crop grown for its dense, edible head — called a curd — that demands steady conditions but rewards patience with a versatile harvest.
Brassica oleracea var. botrytis · also called white cauliflower, colored cauliflower
Windows are counted from the average date of your last spring frost.
Home-grown cauliflower can be harvested at peak sweetness before the curd loosens, and colored varieties (purple, orange, green) are rarely available in shops. Growing your own also lets you time the harvest to avoid the bitterness that develops in overripe heads.
A little history. Cauliflower is a cultivated form of wild cabbage native to the Mediterranean coast. The edible curd is a mass of arrested, undeveloped flower buds; any heat stress during head formation can cause the buds to resume development and the curd to 'rice' (break into grainy, separated segments).
Sow 0.25 inches deep and keep the mix evenly moist; do not let the surface crust or dry out before sprouts emerge. Seedlings emerge in 5–10 days in warm soil.
Beds strongly preferred; containers work only in large volumes — needs at least 12 inches of soil depth and consistent moisture. In containers: 15-gallon pot minimum; one plant per container. Space plants 18 inches (45 cm) apart.
Water deeply and consistently; do not let the soil dry out between waterings. Water when the top inch of soil feels dry to the touch. Aim for 1–1.5 inches per week including rain.
Side-dress (scatter fertilizer along the row and water in) once at transplant, again when the plant is half-grown, and once more when the curd begins to form. What to use: balanced 5–5-5 organic or compost-enriched fertilizer; avoid excess nitrogen once heading begins.
For white varieties, blanch the curd by gathering the outer leaves up over the developing head and securing them loosely with a rubber band or twine once the curd reaches 2–3 inches across; this prevents yellowing from sun exposure. Colored varieties do not require blanching.
It's ready when curd is firm, compact, and 6–8 inches across with tightly packed segments; harvest before segments begin to separate or the surface turns grainy or discolored. Cut the main stem 2–3 inches below the curd with a sharp knife in the morning; remove the whole plant including roots to reduce disease carryover.
Wrap unwashed curd loosely in a damp cloth or perforated bag; refrigerate at 32–35 °F (0–2 °C) for up to 2 weeks. Blanch and freeze for longer storage.
Sow a new batch of transplants every 3 weeks from late winter through early spring, and again from midsummer onward, to extend harvest across both cool seasons.
Celery
Gardeners have long paired celery with cabbage-family crops, and the two do share a need for steady moisture and rich soil, so they can be tended on the same watering schedule. No pest-deterring effect has been demonstrated.
Onion
The strong smell of onion foliage can help hide cauliflower from pests that locate their host by scent, such as the flies that lay cabbage root maggot eggs. Results vary, so keep row covers and stem collars as the main defense.
Garlic
Garlic's pungent leaves can confuse pests hunting by smell and often reduce early aphid settling on nearby brassicas. Garlic is shallow-rooted and low, so it takes little light from the cauliflower rosette.
Nasturtium
Cabbage aphids and some caterpillars often settle on nasturtium first. Treat it as a sacrificial planting a few feet out from the bed and pull or wash down heavily infested growth rather than leaving it as a pest nursery.
Dill
Dill's flat flower heads feed hoverflies, lacewings, and the tiny parasitic wasps that attack cabbage aphids and cabbageworms. Let a few plants flower at the bed edge, and give them their own space so they do not compete with the heads.
Strawberry
Old charts keep strawberries away from cabbage-family crops, and no mechanism has ever been shown. The practical issue is simpler: cauliflower is a hungry, wide plant that shades and crowds a low strawberry bed you cannot easily dig around.
Tomato
Tomatoes are tall, heavy feeders that shade a cauliflower rosette just as the curd needs light and steady food, and they peak in the heat that pushes cauliflower to rice. Give each its own season and space.
Give the cabbage family 4 years away from this spot before any of its relatives return.
The tomato family, the pea and bean family or the carrot family thrive in this ground next season.
Cauliflower is a heavy feeder that leaves the bed short on nitrogen and full of leafy debris — clear every stump and leaf. Keep cabbage-family crops out of this ground for 4 years, then follow with peas or beans, a nightshade such as tomatoes, or carrots and their relatives.