History
Broccoli is perhaps the most unusual of all vegetables. Botanically speaking it is not much different than a cauliflower. Like the cauliflower it is an immature flower of a plant belonging to the cabbage family and like the cauliflower it stops growing while it is still in bud. Its origins too are linked with the cauliflower as wild cabbage (a common ancestor to all brassicas) can exhibit freak growth in the form of non-maturing flowering buds quite independently. So forms of proto-broccoli could have existed in the wild for centuries independently and in many different places.
In terms of modern cultivars however reports are conflicting which came first. It seems that cauliflower may have been bred from these early forms of broccoli as cabbage was first grown for its shoots rather than its compact head as it is today.
It was not until 1724 that the first published reference to broccoli emerged in an edition of Miller’s Gardeners Dictionary where it was called Sprout colli-flower? or Italian Asparagus. So as the latter name suggests its origins are likely to be Italian and it seems that it was introduced to the rest of Europe around the same time as the reference was published in the early part of the 18th Century.
Nutrition
As broccoli consists of immature flowering buds which would normally contain the energy for a plant to fruit it is very high in nutrients and often termed as a super-food.
It is very high in Beta Carotene the precursor to Vitamin A (100g contains 500 micrograms of carotene)
It is also high in vitamin C although a lot of this is lost through cooking
It also contains significant amounts of potassium, folic acid and several phytochemicals.
Broccoli can also be a good source of calcium and this can be enhanced if the soil is limed, as calcium-deficient soil will produce calcium-deficient crops.
Growing Broccoli
Seed should be sown in the spring in fertile soil. They should not be placed in where they could be exposed to strong winds as they can be fairly tall growing. Sow thinly in rows 8cm (3 inches) apart allowing 15cm (6inches) between each row. If growing from seedlings then they can be planted out after they have grown to about 8cm (3 inches) tall. Plant them in firmly, setting them down about 3cm (1inch) deeper than they were in the seed bed. Water well after planting.
Weeds should be kept at a minimum around your crop, so regular hoeing is an essential. You should also consider putting up some netting as bird can destroy broccoli.
Apply a mulch in the summer months to retain moisture. Watch out for pests as broccoli is a troublesome crop.
In the colder months draw up the soil around your plant.
Your crop should be ready to harvest about 10 months after sowing or when the flower shoots have appeared. Cut off the central spear first as this will encourage growth of new spears for harvesting.