Sow calabrese in modular trays, to minimise root disturbance when transplanting later. Fill the tray with seed compost, water well, then sow two seeds into each module, 2cm (¾in) deep. Calabrese is a member of the cabbage (brassica) family, so should be grown alongside its relatives in crop rotations and protected from the main brassica pests and diseases – see Problem solving, below. You can also sow in autumn and overwinter the young plants in a greenhouse, to plant out the following spring for an early crop. Calabrese doesn’t transplant well in warm weather, making it prone to bolting (premature flowering), so after April it is best sown in its final position outdoors (see below). Seedlings should appear within a couple of weeks. As soon as they are large enough, thin them out to one seedling per module.

To grow well, plants need a wide range of nutrients in various amounts, depending on the individual plant and its stage of growth. The three key plant nutrients usually derived from soil are nitrogen, phosphorus and potassium, while carbon, oxygen and hydrogen are absorbed from the air. Other vital soil nutrients include magnesium, calcium and sulphur. Gardeners can add nutrients by applying fertilisers (either artificial or naturally derived) to boost plant growth and improve flowering and fruiting. nutrients are at their peak.

Growing calabrese from seedFrom February to April, you can start calabrese seeds off in a greenhouse or on a windowsill. This should give reliable results, as seedlings are protected from harsh weather and pests such as slugs, however calabrese doesn’t like root disturbance, so take great care when transplanting. Sowing indoors is also preferable if you have clubroot disease in your soil, so the plants can develop a strong root system before being moved outside. Broccoli plants (also known as sprouting broccoli) produce much smaller clusters of purple or white buds on the tips of leafy stems. For more on this crop, see our guide to growing broccoli Calabrese and broccoli are two different crops, but they are often muddled up, with both plants widely referred to as broccoli. But in gardening terms there’s a clear distinction: