Broccoli
Green broccoli is a relatively new crop - the older books barely mention it or do not mention it at all. But in recent decades it has become a popular vegetable. It is very nutritious with good supplies of vitamins and anti-oxidants and it is versatile in cookery, being used as a hot vegetable, steamed or stir-fried, and raw or par-boiled cold in salads.
There is some confusion about the name green broccoli, correctly it is called calabrese. That n
ame is derived from the region of Calabria, the ‘toe' of Italy where this crop originated. It was probably Italian influence on American cookery that expanded interest in this vegetable. Incidentally, the word broccoli means ‘little buds', in this case the massed flower buds of the plant, which is the part that is eaten.
Site and soil
Green broccoli is a very fast-maturing crop and is best planted in a light, open but fertile soil. The soil can be quite rich and following on potatoes should be ideal. The soil should be dug over and loosened before planting, well cultivated, but not firmed as is the case with many other cabbage family vegetables. It needs to root deeply very quickly. It likes warmth early its growth and a space in full sunshine and good shelter should be chosen if possible. But it should not be overly sheltered either.
Varieties
There is a range of varieties available from the seed houses, some are earlier to crop and others take a little longer. ‘Lucky' is early and small-growing and can be spaced accordingly. ‘Arcadia' has tight heads, quick-maturing and very reliable. ‘Green Comet' is quick maturing with large and tightly formed heads. ‘Decathlon' is a vigorous grower that resists summer heat, and does well on less-fertile soils. ‘Belstar' and ‘Ironman' are later-maturing in late summer and into autumn from successional sowings and both of these stand well without running to flower. ‘Tenderstem', and the similar ‘Tendergreen', are very fast to mature with small spears, not like the domed heads of the other varieties mentioned.
Sowing
Broccoli is not completely hardy and the plants can be damaged by frost so it is not sown until April or early May. In the milder parts of the country, the seeds can be sown in early April and up to one month later in the colder inland areas. If frost protection in the form of low polythene tunnels, or horticultural fleece covering, can be given, sowing can start a couple of weeks earlier. Sow batches of seeds in succession about three or four weeks apart to July to spread out the cropping.
Calabrese transplants very badly and has a tendency to ‘button' out with the least set-back, such as transplanting or running dry. When this happens the flower bud may develop to only a couple of centimetres across. To prevent this problem, the seeds are best sown directly where the crop is to mature. Sow three seeds at each station, each group about 30 to 40 centimetres apart.
Separate each of these seeds by a few centimetres in a row or a triangle. Sowing three seeds is an insurance against failure to germinate because it is near-impossible to move plants into gaps, as would be easily possible with cabbage. Be careful about snail-damage because a single snail can devour several groups of tiny seedlings in a single night.
When the little plants are growing well at about ten centimetres tall, each station can be reduced to one plant, snipping off the stem just below the seed leaves, and not pulling them out because of potential damage to the roots of the remaining plant.
Seeds can be sown in pots in the greenhouse in March for planting out in April. Raised in a greenhouse, two or three seeds should be sown per small pot and the plants well watered before being taken out of the pots.
Aftercare
Warm weather or drought can cause buttoning and it is imperative to keep the soil moist. This may require rootball watering, especially during very warm weather or breezy sunny weather when the plants can dry out quickly. If the leaves are seen to wilt, there is a good chance that they will prematurely form a small flower head. Calabrese often does not hold in tight bud for very long if the weather is warm, and the soil dry, and the tendency is for the flower buds to continue to develop and flower.
Picking
Harvesting of the crop is usually about ten to twelve weeks after sowing, or a bit longer later in the year. Pick the main bud by cutting it but leave the plant in the ground. Very often, several smaller side-buds will then form and can be picked a few weeks later. Pick the broccoli heads when ready, as they will not stand long and tend to become tough and stringy. They freeze well, or give them away to friends. Successional sowing helps to spread out harvesting.
Troubles
Calabrese is a cabbage family plant and may suffer most of the pests and diseases of cabbage and cauliflower, but because it is quick-growing, it generally avoids most troubles. The principal problems are caterpillars and greenflies. It is often easy to remove butterfly egg batches by hand, but cabbage moth caterpillars can get into the flower head. If this is a problem, horticultural fleece can be used to exclude the adult moths. This pest is more common in very sheltered gardens. Given the short maturing life of the crop, it is not usual to use any insecticide but derris or natural pyrethrins, which break down within one day, could be used if there is a greenfly attack.