Cauliflower

Brassica oleracea var. botrytis

Each plant makes one white head, called the curd, in the middle. Cauliflower is the fussiest of the cabbage family. Anything that holds it back, like dry soil, loose ground or late planting, gives small heads that form too early. So keep it growing steadily. In a pot, grow a mini variety.

Looking after it

Water: It needs a lot of water. Keep the soil damp all the time but never soggy, especially while the heads form. A mulch holds the moisture in. A pot needs water whenever the compost starts to dry. Feeding: Cauliflower needs rich soil. Dig in compost before planting. On poor soil, give young plants a fertiliser rich in nitrogen before the heads form.

Harvest and keeping

Cut the head with a few leaves once it is firm, before it starts to break apart. In summer sun, fold a few leaves over the curd to keep it white. In winter, tie them over it to protect it from hard frost. It's best eaten fresh. With a few leaves left on, it keeps several days in the fridge. You can also freeze the florets after a quick dip in boiling water.

What can go wrong

Tiny heads. Small heads form too early after something has held the plant back. Plant young plants on time into firm soil and water steadily.
Club root. The plants stay small, wilt on warm days and have swollen, knotted roots. There is no cure and it stays in the soil for years, so add lime to acid soil until it reaches about pH 6.5. Grow these crops in a new bed each year and start plants in pots, so they go out with strong roots.
Cabbage caterpillars. From early summer to autumn you find holes in the leaves and green caterpillars. Cover plants with fine insect mesh from the day you plant them. Rub off any clusters of yellow eggs under the leaves.

Growing facts: RHS, UC ANR and seed-company sowing guides. Cauliflower care and keeping: RHS. How many to grow: University of Missouri and Kansas State extension. pH: University of Minnesota extension.