Cauliflower needs a long season. Seedlings, sown in the autumn, can be wintered over free of frost, in hotbeds or a greenhouse and set out in spring when the risk of frost is over. Sowing in greenhouses in Jan.- Feb. may produce mature cauliflower plants in northern European climes, if the autumn is really long. Throw away plants which are not typical of the sort and also the ones with through-grown or hairy heads. Cauliflower belongs to Brassica oleracea and can cross-fertilize with other kinds of cabbage. Read more under "how to grow cabbage plants".