Cauliflower is a difficult veg to grow well, takes up a good deal of space and doesn’t store particularly well - so when it comes to deciding whether it’s worth growing you really have to consider how much you like to eat it. Home-grown cauliflower is definitely tastier than the mass-produced alternative.
A foolproof way to grow healthy cauliflower seedlings is to sow them in module seed trays – sow one or two seeds in each module 1.5cm deep. Thin out the weaker seedling. They will germinate in about a week and will be ready for planting about three weeks later (when 5cm tall). Make sure to harden off early sowings carefully. For a steady supply of cauliflower, sow a few plants in March, May and June. Spacing will determine the size of the curds - between 60-70cm is about right. The more space you can give them, the healthier the plants will be. As with cabbages, cauliflowers should be planted in to firm, fertile, free-draining ground – the root and stem will eventually have to support a very heavy head! Water plants well before sowing – create a hole with a dibber, pop the seedling in and then firm in very well. Include cauliflower in your brassica rotation – do not plant them where there have been brassicas for at least 3-4 years previously.
Keep plants free of weeds and water regularly – if they dry out they are inclined to bolt. Late sowings can be given a feed of an organic liquid feed to encourage growth. You can protect curds from sun and frost damage by folding some of the surrounding leaves over the curd and tying with a rubber band or some twine.
Harvest while curds are white, packed firm and tight. Remove the plant from the soil and cut the head from the stem. Wash carefully (slugs can make their home in the base of the curds).
Cabbage Root Fly maggots eat the roots causing the plant to stop growing. Prevention is better than cure – 15cm wide “collars” made from felt or carpet placed around the stem at soil level, can prevent the adult fly from laying its eggs. The other major pests are butterfly (large and small white) and moths which lay their eggs on the underside of leaves – the resulting caterpillars will munch their way through your crop in no time. You can remove the caterpillars as they appear, but again the best option is prevention – cover your crop with appropriate netting to stop the butterfly laying its eggs on the leaves. A more serious (though less prevelent) problem is clubroot, a fungus which can stay in the soil for up to 20 years. Acidic soils can cause “tip-burn” which discolours the curds.