Broccoli is an indispensably important vegetable with a history. The plant originated in Europe, possibly in Italy. There it evolved from a wild cabbage through selective breeding by the Romans. It has been consumed there in several forms for at least 2000 years.
Roman colonization allowed Broccoli to spread throughout the continent and into the Middle East and Asia. Italian Immigrants first imported it into the USA and the Southern Hemisphere, especially Australia, New Zealand and South Africa in the 1920’s.
Today Broccoli is an important commercial crop grown in great numbers in: China, India, U.S.A. Spain, Italy, France, Mexico, Poland, Pakistan and the United Kingdom plus to a lesser degree in most other countries with temperate climates. In cooler and moderate climates Broccoli can be grown all year but it is primarily grown and understood to be a ‘cool season’ vegetable, often grown from Autumn through Spring.
Broccoli oleracea is a species member within the genus Brassica which is a grouping of related plants of the Brassicaceae (Cabbage or Mustard) Family. Included here are many weeds plus 30 wild species and several very important Vegetable species. These include: Broccoli, Brussel Sprouts, Cabbages and Kales plus Savoy, Cauliflower, Chinese Broccoli, Collard Greens, Kohlrabi, Mustard and Rape seed, Rutabaga, Turnip and a few more lesser-known species.
Abundant research has confirmed Broccoli to be one of the most important of all Vegetables. It is very high in Vitamin C, dietary fiber and Beta Carotenoids plus Lutein and Selenium. It also contains high quantities of Diindolylmethane, an anti-carcinogenic potent modulator of the innate immune response system. Broccoli also contains Indole-3-Carbinol which boosts DNA repair in cells which is a further blocker of cancer cells. The organosulfur chemical agent Sulforaphane is also highly anti-cancerial provided the Broccoli is not overcooked. Best and highest levels occur when steamed for no more than 3-4 minutes.
This means that Broccoli is anti-cancerial, anti-bacterial, anti-viral and an important aid in proper digestion and elimination. There is conclusive evidence that generous and regular consumption of Broccoli is extremely helpful in lowering the possibility of prostate cancer and most other related forms of cancer as well as significantly reducing the risk of heart attack. All this makes Broccoli quite a valuable healing Vegetable which off-sets its somewhat disagreeable reputation for causing ‘malodorous flatulence’. A full listing of all the nutritional values of Broccoli is contained in the chart at the end of this article.
There are several types of Broccoli commonly grown in gardens today.
The most common and popular of these is known as Full Head, Italian or Calabrese Broccoli, named after the Italian city of Calabria where it is said to have first originated. This is the classic green-headed Broccoli of which there are now numerous cultivars and hybrids. The plants are upright with blue-green-grey leaves often with a soft, powdery bloom and numerous compound lobed somewhat irregularly shaped leaves extending outward in all directions around a fleshy, thick main stem, trunk.
The Calabrese flower bud heads are usually 10-20cm/4-8inches across and occur at the top of the plant on a thick (edible) stalk with the tightly packed flower buds arranged in close bunches that resemble a small, stocky tree. Broccoli heads are best harvested while compact and young as opposed to loose and beginning to flower; as once the simple cream to yellow flowers begin to open, the flavour of the heads becomes stronger. However, the edible flowers are often used in salads and have a flavour similar to mild Cabbage or Kale.
Once the initial large flower head is harvested by being cut at a slight slant with secateurs, several small side heads will emerge within a few weeks. Some species will branch and produce many smaller heads for several months upward to 18 months. But most Full Head Broccoli produces just one really impressive head followed by a few more side heads and then it is best pulled out. While considered a ‘cool season’ vegetable, there are cultivars and hybrids that will produce crops almost any month of the year.
Sprouting Broccoli is a group of Broccoli cultivars and hybrids that have been produced through natural selection and cross breeding from the original Italian Broccoli. Sprouting Broccoli appears nearly identical to large-headed Italian Broccoli while young. It also produces a large single head of clustered buds atop the classic Broccoli leaves. But this head is somewhat smaller and in some hybrids much smaller with more open florets on thinner stalks. Once harvested the plant branches quite considerably to create a bushy shrub often 60cm-100cm/2-3.34ft. tall and often as broad. This shrub produces numerous small Broccoli shoots on thin stalks. These are edible but often with a more delicate flavour and texture that can often resemble that of Asparagus. “Broccolini’ is one of the finest for edible stalks as well as flower heads.
Sprouting Broccoli will often produce edible crops for 12-18 months. Whenever the plant appears to be spent or is producing very small and thin edible stems, the entire plant can be cut back severely to within a few inches/centimetres from the ground and it will often re-sprout an entirely new plant. In temperate climates Sprouting Broccoli is traditionally sown from seed in Mid/Late Spring for Late Autumn and Winter harvests. In cool climates with moderate Summers and Winters with little frost, Sprouting Broccoli can be sown at almost any time but still favours Spring and Autumn sowings.
Romanesco Broccoli sometimes known as Broccoflower or Green Curd Cauliflower was first introduced during the 16th Century and remains very popular in Europe. The flower heads and growth of this variety most closely resembles Cauliflower. The growing stem is short, stocky and thick with the light green-yellow head of florets tightly arranged at the top and surrounded by a rosette of protective leaves very similar in appearance to Cauliflower. The many-branching bed heads are arranged in a very decorative and interesting logarithmic spiral pattern finishing in many spirally soft points creating natural fractals.
Romanesco Broccoli has a creamy, light almost nutty flavour which is less bitter than either Broccoli or Cauliflower. But it is important to not over-cook this vegetable, just a few minutes will do, otherwise its flavour and texture become less desirable and much of its nutritional qualities are lost. Romanesco Broccoli usually only produces a single large head and then it is finished and the plant can be removed. Occasionally, if the plant is cleanly cut back with secateurs, it will re-sprout several more leafy florets from the stem stump which will later produce several more small edible heads. Seed can be sown in Spring or Autumn. In moderate climates with cool Summer weather and mild nearly frost-free Winters, Romanesco Broccoli can be planted or sown almost all year. In hot climates with frost-free Winters, sow or plant in Autumn for Winter and Spring harvests. In climates with Winter freezing but cool to mild Spring and Summer weather, sow or plant in Spring for Summer and Autumn harvests.
Purple Cauliflower is almost identical to regular Cauliflower and very similar to Romanesco Broccoli only the softly lobed and rounded heads of tightly-packed florets are tinted with pink or purple pigmentation. Some resemble exactly a traditional Cauliflower with a pink of purple tinge while other hybrids can be bright pinkish purple or bold deep purple. Other hybrids can produce curds that are shades of blue, lavender, lilac, and mauve, many shades of pink and purple plus occasionally apricot, orange and even red! The colour is retained both raw and when lightly cooked and they make an unusually conversation piece in salads. Their taste is almost identical to traditional Cauliflower.
These delicious, mineral rich vegetables have been hybridised so that they can be grown for much of the year. But Broccoli in all its forms is still best when grown as a ‘cool season’ vegetable. Thus in climates with cool Summer weather and mild Winter climates with only occasional frosts, they can be planted or sown all year. But they are best sown from seed or transplanted from advanced seedlings during Early/Mid Autumn and again in Spring. The Autumn sowings will provide the best Late Autumn and Winter harvests often lasting into Spring. Spring planting will produce Summer and Autumn harvests. When sown in Spring, care must be taken to insure a cool root run. In climates experiencing hot or scorching sunlight, they may need a bit of sun screening plus protective mulching.
Choose a sunny site with some wind protection. All Broccoli cultivars do best growing in temperatures between 18-23C/64.4-73F and seed germinates best within this range. Hotter temperatures will often result in poor germination and little if any flower head production. Yet the plants can easily tolerate an air and soil temperature range between 7-30C/44.6-86 and often even more extreme than that in air temperature!
Seed will usually germinate within 10 days. Seedlings transplant easily at about 4-6 weeks. They can also be grown on in individual small containers to a much larger size which can then be transplanted to their final garden space. Larger plants must be transplanted with more care to not damage their root system. Once transplanted, each plant will produce its best efforts when spaced 35-50cm/14-20in. apart in all directions.
Because of the issue of root disturbance potentially checking later growth, Broccoli and all Brassica are often sown and grown-on in separate small containers or punnets. The root ball lifts out easily for flawless and simple transplanting success.
Another more radical approach is to grow a larger number of seedlings in either a seedling flat or punnet. When grown in a seedling flat, the entire group of seedlings can be grown-on as a single unit. Usually this is most effective when the seedling flat is placed over cultivated and enriched earth where the seedling roots can penetrate through the bottom of the container and feed on the enriched soil below. When successful, one or two of the strongest plants will produce the first and largest heads. But this will be followed in succession by the smaller plants. While each head may be smaller, the seedling flat can often produce a continue supply of smaller heads over six months or more. This often suits an Individual Gardener whose vegetable requirements are considerably less than a Family.
Alternatively, an entire punnet containing four to ten seedling plants can be planted as a single unit in enriched earth. Provide plenty of space between punnets as each punnet colony will spread out to make a large shrubby mass of plants. Feed regularly and water generously. Once again, the strongest plants will produce their heads first, followed in succession by the smaller plants. While each Broccoli head will be smaller, they often produce enough for the small Home Gardener.
The Colony planting system works very well for Broccoli, Collard Greens and Kale, Mustard Greens and Rape seed but to a lesser degree with the ‘heading’ Brassica like Cabbages, Cauliflower and Romanesco types. These need considerably more room to develop to their full potential. But for the Individual and small Home Gardener, growing Broccoli and similar Greens in a colony system saves space and produces just enough for a fresh and vitamin-enriched meal. In such situations, there is little advantage to raising large quantities of these healthy green Vegetables that mature all at once. Better to raise a few plants every month or easier still, raise small colonies. For while Broccoli and all the Brassica are most healing and nutrient-rich when consumed fresh or lightly cooked, they lose much of their nutritional benefit when frozen, then thawed and re-heated.
Mature Broccoli plants can often withstand mild frosts and short freezes but the flower heads will be tainted and probably will need to be cut back to allow small side shoots to form for a proper harvest. They respond well to being covered over with protective frost cloth. Alternatively, Broccoli can be raised in the unheated or very cool and sunny glasshouse or high-built cold frame. They are best raised from in-ground plantings or in large planters or tubs that allow the free spread of their extensive root systems.
Broccoli along with all other related Brassica vegetables perform to their very best when sown into a cool to moderate climate with ample rainfall and bright sunlight. Under these conditions they will often produce crops within 60-90 days. But when conditions are less ideal, they may take many months longer until harvest. Often when planted in Autumn, they will begin to produce crops whenever a few days of sunny and warm weather present themselves; otherwise as soon as weather breaks in Late Winter or Early Spring.
Broccoli and its relatives will grow in a variety of soils. Broccoli will produce crops in average soil but prefer those enriched with compost and well-rotted manures. They all prefer alkaline soils with a high Lime content and thus a relatively high soil pH. They will survive in acid soils of pH 5.3 or more but prefer at least pH 6.0 and ideally pH6.8-7.3 or even higher.
They most prefer loamy land, like pasture land, with a bit of body but free drainage. This free drainage is especially true with Broccoli crops grown through the cooler and damper months. Then they will even grow in sandy land provided feeding and water are amply provided. If water stands around the plants, they will often develop root or crown rot. This is also a contributing factor to Club Root fungus. If this fungus ever develops, stop planting any Brassica plants in the immediate environment. Treat the soil with generous applications of Lime and an appropriate fungal soil drench and attempt to improve the drainage and soil aeration to protect future Brassica crops.
Broccoli love Lime in any form which strengthens them against blights and fungus. Gypsum Lime is ideal in very heavy clay soils as it also helps improve drainage. Garden Lime will give them a quick boost and Dolomite or Dolomag Lime will improve their soil pH over the longer-term. Dolomite Lime is very beneficial in acid and lighter soils.
Many Gardeners also add a balanced General Garden Plant Food such as a ratio like 10-10-10 or 20-20-20. And because Broccoli is a leafy Vegetable, they respond very well in their early stages to additional Nitrogen to promote leafy growth. This could be organic Blood and Bone, mature compost, aged manure or Nitrate of Soda. Add this to the soil several weeks prior to planting or as a side dressing once the plants are established and growing strongly.
This extra Nitrogen also can be supplied organically by planting into soil which has recently grown a healthy crop of Beans, Clover, Lupines, Peas or other Nitrogen-producing legumes, especially if their vegetation has been dug into the soil. Maintaining high levels of Nitrogen in the early stages of plant growth will insure large and leafy, stocky plants that will produce the biggest flower heads.
Once plants show the first signs of flower buds/curds developing in the centres, shift to a fertiliser higher in Phosphorous and Potassium to encourage better bud, curd, pre-floral development over leaf production. This might be organic Phosphate Rock or Superphosphate; granite dust, Green Sand or Sulphate of Potash; well-composted seaweed or aged compost produced from fruit and vegetable scraps. Too much Nitrogen during bud/curd production can produce large leafy plants but smaller Broccoli heads, although this usually is less of a problem with Sprouting Broccoli.
Keep the young plants growing strongly at all times. The most essential requirement here is good sunlight and ample moisture. If Brassica Family plants ever dry out or sustain severe root damage while young, this will often ‘check’ their growth. This often appears as a brown, cream or soft beige band low upon the growing stem although sometimes nothing will show at all. But the obvious result of root or water stress is permanent stunting. The plants remain small and never attain their full size. Sometimes they will produce a small harvest, but often this is minuscule. Once growth is checked usually no amount of care of feeding will alter the diminished results. It is often best to pull these plants out and start again.
If conditions remain dry consider mulching the plants. In very warm climates or whenever hot sun is expected, mulching is essential to keep the plant roots evenly cool and moist. Always make sure to artificially irrigate all Brassica Family plants unless regular rainfall is generous. Guard against the Caterpillar of White Butterfly with Derris Dust or a suitable insecticide or herbal spray. This should not affect the harvest provided nothing toxic is sprayed upon them for at least 4-6 weeks prior to harvest. Small plants must also be guarded against the ravages of Slugs and Snails that can decimate a young crop overnight.
Aphids as well as Beetles and Caterpillars can be stopped organically by placing a bird feeder in or near to the Brassica patch. Fill the feeder with protein-rich Finch and Sunflower seeds. This will attract protein-feeding Birds that will also eat Aphids and Caterpillars. If the feeder is installed several weeks prior to planting the crop, helpful Birds will already be nearby in significant flocks by the time of planting. The young seedlings may need covering against the Birds at first. They usually do not eat Broccoli but in times of famine, they will consume almost any tender, young green vegetable foliage. But once their leaves become more mature and bitterer, the Birds will perch upon them and pick off every predatory insect from the developing Broccoli heads without the need for toxic spraying.
When harvesting, cut the heads on a slant with a sharp knife or secateurs while still in tight bud with a generous stem. Tight cuts heal faster and slanting forces dew and rain to drain away; rather than collect and promote stem rot. It is much better to cut Broccoli a bit too early than to wait until too late! New smaller side shoots will soon appear and can continue into Spring. These slender side stems often resemble Asparagus in taste and texture.
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