One of the finest types of broccoli to grow is ‘Early Purple Sprouting’ although the fine green heads of other kinds are highly regarded.
Broccoli or Calabrese is usually sown outdoors from late winter – early March to mid-spring such as late May, very thinly in a seed bed dedicated to the crop alone. Seeds sown as early as possible appear to produce the best plants we’ve noticed but a decent crop can be obtained with late sowings. I’ve noticed they almost leap out of the pot once they’ve started. The seedlings must be allowed to grow on until they are large enough to be planted in their cropping positions, usually elsewhere in the garden.
Seed needs to be sown thinly, about 1.5cm deep into a soil which has been tilled to a fine, crumbly texture. This will have been watered previously and once the seeds are sown covered over. Most seedlings appear between 2 and 3 weeks.
Seeds can also be sown in a propagator if late winter is really too harsh. In mild spells they will germinate on greenhouse staging or in a propagating tray which has some under heat.
The ground needs to be kept well watered if the ground dries up. A watering can with a fine rose is ideal until the plants are fully established in the ground.
Seedlings are transplanted when they are above 10cm tall. They must be carefully handled using just the leaf and not the stem which could damage the young seedling. The seedlings are laced 60cm apart in all directions, firmed and watered in well.
The other technique is to sow indoors into compost or John Innes No. 1 compost about 0.5cm deep. This is watered beforehand and placed in a cold frame or unheated greenhouse. The soil is kept moist and the seedlings transplanted to other trays at 5cm apart. Once they have sprouted, the seedlings should be large enough to handle. The young crops are accustomed to the outdoors before planting out in July or August.
The shoots of sprouting broccoli are cut when 15 cm long from February to May.
Cut main heads promptly and side shoots will then produce secondary and even tertiary pickings.
Cultivars Of Broccoli And Calabrese
cv. Ironman – reliable, producing dense, domed heads of blue-green flower buds. Holds well, re-sprouts vigorously and tastes great.
cv. Monciano – dense green heads and lots of tasty side shoots as usual but this one has good resistance to club root.
cv. Broccoli ‘Kabuki‘ – an early variety cropping 65 days after planting out. Plant 15-17cm apart for ‘baby veg’. Ideal for pots or small raised beds.
Clubroot Resistant Varieties To Try. If clubroot is a major issue on your soil, then try the Brassicas collection from Simply Seeds which has four resistant varieties for sowing. They include a cauliflower (cv.Clapton), brussel sprout (cv. Crispus), calabrese (cv. Monclano) and the cabbage (cv. Kilaton).