Broccoli is a highly popular, tasty and versatile veg, famed for it’s high content of vitamins and ‘anti-cancer’ properties.
Broccoli falls into three categories, purple and white sprouting and calabrese (the green varieties). Calabrese is harvested in autumn, extending into winter if the weather is mild whilst the hardy white and purple sprouting types are overwintered and harvested in the spring, handily providing veg between the end of the sprouts season and the beginning of the spring cabbage harvest. Broccoli is part of the Brassica family of vegetables. Although some root veg are classified as Brassicas, the term is usually reserved for those veg we grow as ‘greens’, such as cabbage, sprouts and broccoli.
Soil & Growing Position
All brassicas prefer a reasonably sunny spot and firm, rich ground so dig in some organic matter such as Farmyard Manure or compost, , ideally during the winter prior, to allow the soil to settle and consolidate as brassicas dislike loose soil and freshly manured soil. Mulching around the growing plants will help to retain moisture. Remember to plant any veg of the brassica family in a different patch of soil each year to stop the build-up of diseases such as clubroot (see Soil Preparation and Crop Rotation). If you have very acidic soil, add in some lime during the winter as this will also help to control clubroot. You can test your soil’s acidity by using a Soil Testing Kit. Brassicas are quite nitrogen hungry so they thrive in ground where peas and beans have previously grown (see Crop Rotation). Apply a general fertiliser to the soil a couple of weeks prior to sowing or planting. Broccoli plants can grow up to around a metre in height so may need staking on windy or exposed sites.
Sowing from Seed
Sow from March in mild areas, April to May for the rest of the country and in June for the later varieties. In a prepared seed bed (see VegGrowing from Seed), sow the seeds thinly in rows of 15cm (6in) apart and 13mm (0.5in) deep.
For earlier cropping, seeds can also be sown indoors/under glass and planted out at the 5-6 leaf stage, although Calabrese is best sown where it is to crop.
Growing on and Young Plants
When the young broccoli plants have four or five leaves /10-15cm (4-6in) high, transplant to their final positions leaving between 30 cm (12”) 45cm (18”) depending on variety. Do check, as some varieties require more space such as Nine Star Perennial which needs around 90cm (36”). If you are short on room, choose a small-headed variety such as Broccoli Kabuki F1 which was bred for close spacing, 25-30cm (10 to 12 inches) apart each way. Directly-sown Calabrese can be thinned to 30cm (12”) apart.
Ensure the plants are watered well the day before lifting and again after transplanting. Plant the seedlings firmly, about an inch deeper than in the seed bed. As brassicas prefer a firm soil, do not fork over the soil before planting. Instead lightly rake the surface and tread down the soil prior to planting.
Calabrese grown from seed takes around 12 weeks from sowing to cutting whilst Purple and White Sprouting Broccoli takes 44 weeks from sowing to harvest so there is a good case for buying young plants rather than seed! Furthermore, if you start from young plants, you'll miss out the first couple of months when the little seedlings are at their most vulnerable to predators such birds, caterpillars, slugs and snails.
Crop Care
Feed during the summer with a liquid fertilizer such as Liquid Growmore and water well during dry spells. Mulching will help to retain moisture. Use Cabbage Collars around the plants to stop cabbage root fly. Keep an eye out for pests such as caterpillars and aphids. Birds can be a problem, so net the plants when the heads are being produced. Using a growing tunnel of micromesh is a very easy way to protect your young crop from the risk of birds and in particular caterpillars and aphids but don’t be tempted to take it off as that let’s the blighters in! The micromesh lets through sufficient light and water so can remain in place. If you find your plants get too big for the tunnel, remove it and replace with netting to keep those pesky birds off.
Harvesting
Cut when the spears are well formed but before they break into flower. Start with the central spear first and then cut the sideshoots. These can be picked regularly over four to six weeks but do not strip a plant completely. Cropping lasts for around six weeks but avoid letting any of the spears flower as this will end cropping prematurely.
