How to grow broccoli (Calabrese)
Broccoli has long been hailed as one of the world's most powerful "superfoods" due to its beneficial properties that include two major antioxidants or cancer-fighting substances. Studies have shown that broccoli is particularly effective in the prevention of both breast and bowel cancer.
Broccoli is a half hardy perennial that is grown as an annual. The green varieties or Calabrese are planted in spring and harvested in autumn, whilst other varieties take almost a full year to mature.
Broccoli is a half hardy perennial that is grown as an annual. The green varieties or Calabrese are planted in spring and harvested in autumn, whilst other varieties take almost a full year to mature.
Types of broccoli
Broccoli belongs to the Brassica family and is related to the cabbage. There are a number of popular varieties that are grown throughout Europe. The most common type of broccoli that is consumed in the UK is actually known as Calabrese, although it is often labelled as broccoli in the shops and supermarkets.
Calabrese consists of a large, domed, dark green head made up of smaller florets, with a thick stalk, and has a milder flavour than other types of broccoli.
Broccoli generally produces smaller heads and is purple or white in colour. These types of broccoli are more popular in southern European countries such as Italy and Spain.
Romanesco broccoli resembles a cauliflower in appearance and consists of small, tightly formed swirling, flowery heads that are bright green in colour, and are surrounded by thick, dark green leaves.
Calabrese is easier and quicker to grow than other types of broccoli, with only 15 weeks to harvest from planting. Broccoli requires approximately 40 weeks.
Calabrese consists of a large, domed, dark green head made up of smaller florets, with a thick stalk, and has a milder flavour than other types of broccoli.
Broccoli generally produces smaller heads and is purple or white in colour. These types of broccoli are more popular in southern European countries such as Italy and Spain.
Romanesco broccoli resembles a cauliflower in appearance and consists of small, tightly formed swirling, flowery heads that are bright green in colour, and are surrounded by thick, dark green leaves.
Calabrese is easier and quicker to grow than other types of broccoli, with only 15 weeks to harvest from planting. Broccoli requires approximately 40 weeks.
Soil conditions for growing broccoli
As with other brassicas, broccoli should not be planted where other brassicas have been cultivated during the previous two years. For the best results, broccoli should be planted after a crop of peas or beans, as these vegetables leave deposits of nitrogen in the soil, which is much needed by the broccoli for healthy growth and development.
Broccoli and Calabrese thrive in a rich, well draining, medium-heavy soil that has a pH of between 6.5 and 7.5. The soil should be prepared well in advance and allowed to settle.
Broccoli and Calabrese thrive in a rich, well draining, medium-heavy soil that has a pH of between 6.5 and 7.5. The soil should be prepared well in advance and allowed to settle.
Climate conditions for growing broccoli
Broccoli is a cool weather crop that generally thrives in cooler temperatures that do not exceed 30°C (86°F). The ideal temperature for cultivating broccoli is between 18 - 23°C (65 - 75°F).
Broccoli should be planted in an open, sunny or partially shaded area.
Broccoli should be planted in an open, sunny or partially shaded area.
Soil preparation
Calabrese should be sown and planted in the same spot if possible, as they don't fare well when transplanted. They are generally sown in late April or early May and should be protected for the first few weeks if frost still persists.
Prepare the cultivation patch in the autumn or winter by digging the soil thoroughly, removing any large stones and weeds, and by adding plenty of organic material such as manure or well-rotted compost. If the soil is weak or particularly light, add some nitrogen fertiliser as well.
Prepare the cultivation patch in the autumn or winter by digging the soil thoroughly, removing any large stones and weeds, and by adding plenty of organic material such as manure or well-rotted compost. If the soil is weak or particularly light, add some nitrogen fertiliser as well.
Sowing the broccoli seeds
Sow broccoli seeds thinly, in April or May, approximately 2.5cm (1 inch) deep in rows that are 60cm (2ft) apart. Cover the seeds loosely with soil and water well. The seeds will germinate within about 10 days and then the seedlings can be thinned out to 30cm (1ft) apart (for Calabrese).
Caring for the broccoli plant
The broccoli (Calabrese) plant is generally easy to care for and the novice gardener should not have too much trouble with this crop.
Mulch around the plants to ensure moisture retention and water well in dry weather. However, be careful not to water too much as broccoli is susceptible to fungal disease. Mulching will also keep weeds at bay, but if any do appear be sure to remove them.
Mulch around the plants to ensure moisture retention and water well in dry weather. However, be careful not to water too much as broccoli is susceptible to fungal disease. Mulching will also keep weeds at bay, but if any do appear be sure to remove them.
Broccoli pests and diseases
As with other brassicas, broccoli may also be affected by caterpillars, cabbage root fly and aphids. The cabbage root fly and cabbage root both affect the roots of the broccoli, causing them to swell and distort, and in the case of cabbage root fly, rot with maggots. Both can be prevented by chemicals.
Harvesting the broccoli
Calabrese is an extremely fast-growing crop and some varieties will be ready to harvest from anything between 40 - 65 days. If sown in April or May, the broccoli should be ready to harvest from July onwards until November.
Harvest the broccoli when the side florets start to loosen slightly but the main head is still very compact. Cut the Calabrese at the base of the stalk, so that the main head is removed.
Harvest the broccoli when the side florets start to loosen slightly but the main head is still very compact. Cut the Calabrese at the base of the stalk, so that the main head is removed.
Storing the broccoli
Broccoli may be refrigerated but only for up to a week. For the best results, blanch the broccoli florets in boiling water for approximately 3 minutes, allow to cool for several minutes and then freeze.
