broccoli

Grow broccoli as an annual vegetable: start it in spring, plant it outdoors from May, harvest from summer to autumn, after which the plant dies off; you do not overwinter normal summer varieties. If you want to harvest the following spring, choose a winter broccoli variety (e.g. Purple Sprouting), sow it in summer and cover it with horticultural fleece or brushwood in hard frost.

You propagate broccoli exclusively from seed; cuttings or division are not standard practice with brassicas. For saving your own seed, be sure to use open-pollinated varieties (e.g. ‘Calabrese’ or ‘Rasmus’); F1 hybrid varieties do not produce true-to-type seed.

Spring growing: From February or March, sow indoors in low-nutrient seed compost, about 0.5 cm deep; broccoli is a dark-germinating seed, so cover the seeds well. At 15 to 20 °C the seeds germinate within around 7 to 14 days. As soon as the seedlings show their first true leaves (about three to five leaves), prick out each plant into its own pot. After about 4 to 6 weeks, when night frosts are no longer a threat (from mid-May), plant the young plants out in the bed at a spacing of 40 to 50 cm.

Summer sowing for the autumn harvest: A second sowing period runs from May to July, directly outdoors or in a seedbed. Starting them in trays is safer here too, because the seedlings are then protected from slugs and weather swings. That way you harvest heads from August to October.

Seed saving: If you want to harvest your own seed, let a few open-pollinated plants flower fully and the pods ripen. This is for the patient, as broccoli often only completes flowering in the second year. As soon as the pods are light brown and dry, cut off the shoots and let them dry further before you extract the seeds and store them cool, dark and dry.