Guide to Growing Cauliflower | How to Grow Cauliflower

Cauliflower is the most luxurious of the brassicas, and the one requiring most care. While other brassicas, such as kale, cabbage and Brussels sprouts, are regarded as reliable standbys, able to cope with the worst winter weather, growing cauliflower is regarded as something of a challenge. It is a very popular vegetable, though, because of its delicate taste and pleasing appearance, and is well worth the extra effort involved. For exhibition work, it carries the highest maximum number of points, and perfect cauliflowers can be the focal point of a mixed vegetable display.

In the kitchen, cauliflower is the most versatile of the cabbage family. Its tightly closed, creamy white flower buds, or curds, can be eaten raw with a salad dressing, boiled and served on their own or as an accompaniment to a main course, or preserved in various pickles. When cooking, cauliflower does not fill the kitchen with that unpleasant cabbage smell, and it is eminently suitable for freezing.

Technically, there are two sorts of cauliflowers: summer and winter. The former is a proper cauliflower, while winter cauliflower is actually a type of broccoli. They look practically identical, however, and both sorts are sold in the market as cauliflowers. They grow on short, tough stems 7.5-15 cm (3-6in), crowned by a cup of leaves which contains the flowering head. The leaves surrounding summer cauliflowers are loose and spreading, while those of winter cauliflowers are tightly curled around the head to protect it. The curds of winter cauliflowers are slightly coarser in texture, but there is really not much difference in taste between the summer and winter varieties.

The names ‘summer’ and ‘winter’ are a bit misleading. Some summer cauliflowers are planted in winter under glass, for harvesting in late spring or early summer. Maincrop varieties of summer cauliflower are sown outdoors in spring for harvesting in summer and autumn. It is unlikely, however, that cauliflower can be harvested in high summer, because of its dislike for hot, dry conditions. Summer cauliflowers are very particular about soil and moisture requirements, and extremely sensitive to lack of nutrients.

Winter cauliflower is easier to grow, but it is much slower growing. It will take up space in your garden for a longer period of time than summer cauliflower; remember this when working out your crop planting plan. Although hardier than summer cauliflower, it will not survive very cold weather. Unless you live in a mild, sheltered area, do not expect to harvest any cauliflower in the depth of winter.

There are dwarf growing varieties available, such as Early Snowball and Bondi, which are suitable for small gardens. Recently developed Australian strains, bred for hardiness, are also available to the amateur grower, and well worth trying.

Suitable site and soil

All cauliflowers need a neutral or slightly alkaline soil to do well. If the soil is too acidic, the plants will be unable to obtain molybdenum, a trace element, and may develop whiptail. However, soils which are too chalky or limey may lead to a boron deficiency; stunted, discoloured and useless curds would result. The best and safest method of dealing with soil acidity is to take a soil test and correct the soil, if necessary, so that the pH is between 6.8-7.0. There should be a minimum of six weeks between liming and manuring. As with all brassicas, avoid using a plot on which a brassica crop was grown within the past two years. Cauliflowers are even more susceptible than most other brassicas to the pests and diseases encouraged by continuous cropping.

Because summer and winter cauliflowers are grown under different conditions, cultivation needs differ. Summer cauliflower is grown quickly and requires an enormous supply of nutrients to make this rapid growth; the soil should be as rich as possible. Work on the permanent bed should be done in autumn, so the soil has time to settle and consolidate before spring planting. Dig the soil to a sufficient depth to take a good layer of rotted farmyard manure or garden compost. The lighter the soil, the more organic matter it needs. It is a waste of time, however, to try to grow summer cauliflower on dry, gravelly soil or waterlogged clay soil. About a week before planting summer cauliflower, apply compound fertilizer at the rate of 120 g per sq m (4 oz per sq yd).

Cauliflower photographed in Woolworths store i...

Cauliflower photographed in Woolworths store in Melbourne, Australia (Photo credit: Wikipedia)

The best site for planting summer cauliflowers varies according to the time of year. Early crops should have a site in full sun and one which is sheltered from winds. It must not be in a frost pocket or low-lying ground. It must also be well away from any overhanging trees or tall hedges, or the plants will be poor. Winter cauliflowers are much more tolerant of soil conditions, and will grow on most types of soil, as long as there is no water-logging. Because they grow slowly over a longer period of time, and have to face winter conditions, the one thing you want to avoid is lush, rapid, and therefore vulnerable growth. The site should have been prepared for a previous crop, such as potatoes, beans or spinach. If plenty of manure has been dug in, there is no need for additional fertilizer prior to planting out winter cauliflower. If you are applying fertilizers, avoid using those high in nitrates. They need a sheltered, rather than exposed, site, and one with some protection from north and east winds. They do better in sun than in shade.

Sowing cauliflowers

The small round cauliflower seeds, particularly those of early varieties, tend to be very expensive, but there are several ways to overcome the initial expense, and still have a good successional supply. Either buy one packet of the variety All the Year Round, and sow in succession, or organize a group of friends and neighbours so that each one buys a variety harvested at a different date. Then divide up the seeds so that each person has a few seeds of all the varieties. The seeds are large enough to handle singly, so there should be no loss in dividing them up or sowing. If properly stored, the seed will remain viable for at least three years, so you can save any extra; 8 g (I oz) will yield about 500 seeds. Do not buy inexpensive seeds; they are more than likely to be inferior strains, and the whole exercise will then be a waste of time, garden space and money.

Cauliflower varieties are divided into four groups, according to the time of harvesting, and the time of sowing is related to this. Seed packets have a sowing date on them; do not sow earlier than this date or the plants may bolt.

Group one contains the earliest summer cauliflowers, which are intended to be harvested in late spring and early summer. These are all dwarf varieties, only 30 cm (1ft) or so high. They should be sown under glass in boxes from early autumn to mid-winter, and will require a constant temperature of 10-16°C (50-60°F) while germinating, but while growing through the winter, a lower temperature of 7-10°C (45-50°F) or thereabouts. They produce a minimum of small, light green leaves which give little protection to the curd; the heads are pure white and delicately flavoured.

Group two is made up of the second earlies, consisting of rather hardier varieties, for harvesting in mid-summer. They are also small, but not as dwarf as those in the first group; the leaves are rather larger and darker. These should be sown in boxes, trays or pots under glass at the same time as the group one cauliflowers. A second sowing may be made outdoors in early spring, although this should be protected by cloches against night frosts and chilly daytime weather. The plants come to maturity a month or two later than those sown and brought on under glass.

The third group contains the main-crops; these are larger and hardier varieties of cauliflower, for harvesting from late summer to mid-autumn. Sow in an outdoor seed-bed in mid-spring, giving some protection against night frosts. Sow in drills 1.2 cm (5in) deep in rows 22-30 cm (9-12in) apart, depending on the variety.

The fourth group consists of a number of dwarf, very hardy varieties, originating in Australia and introduced into Great Britain and the United States in recent years. Sown at the same time and in the same manner as those in group three, they come to maturity rather later and will tolerate a moderate amount of autumn frost. They have compact, high quality, uniform curds, protected by tightly in-curling leaves.

Seed compost is the best medium for sowing under glass. Germination should take place within one or two weeks. With those sown under glass, pricking off or thinning should take place as soon as the seedlings are large enough to handle; they should be at the two leaf stage. If pricking them out into boxes or trays, leave 5 cm (2”) in all directions; if using individual pots put one plant in each.

Early cauliflowers (groups one and two) can be pricked out from mid-autumn into a cold frame to overwinter. Keep the frame open during warm days, and close it at night and in cold weather. In early spring take the frame light off the plants to harden them off for final planting out in mid-spring. These types can also be sown outdoors in early autumn and overwintered under cloches.

If you live in a very mild, sheltered area, you can sow winter cauliflower in mid-spring, for planting out in early summer and harvesting the following winter. Otherwise, it is best to delay sowing until late spring, planting out in mid-summer and harvesting the following spring.

Planting out

Transplant young seedlings to the prepared outdoor bed when the plants have about five leaves and cloche the varieties in groups one and two, if frost is likely. Do not leave it later than mid-spring, even if the weather is cold and windy. The young plants, if allowed to grow too big and lush before transplanting, will be unlikely to form good heads. Reject any plants which are ‘blind’, that is, those which have no visible growing point; they will never develop any further. Also do not plant any that have a markedly blue tinge compared with the other plants—these will not develop good hearts.

Take great care to avoid any check to the plant when transplanting, as this is one of the main reasons for small or nonexistent heads. Do not plant the roots too deeply. In times of drought, water both the plants and the prepared bed before transplanting. Keep a ball of soil around the roots during the transplanting, and lift only half a dozen or so plants at one time, to avoid dried out roots. Use a trowel rather than a dibber; although for winter cauliflower, which appreciates a firm soil, a dibber is better. In warm, sunny weather, fill each individual hole in the soil with water, insert the plant roots, and firm the soil around them. This ‘puddling in’ ensures that the roots come well into contact with moist soil, and the plants can establish without any check. It is especially important for winter cauliflower.

For crops in groups one, two and four, plant 45 cm (1’ 6”) apart in rows 60-90 cm (2-3’) apart. For crops in group three, allow 60 cm (2’) between the plants.

Care and development

The secret of success with summer cauliflowers is rapid and continuous growth. From transplanting time onwards they need copious watering; if checked at any time, they are liable to ‘button’ or form very small heads. Even though the soil may have been very rich as a result of its preparation, it can do with even more feeding. There are several methods. One is to mulch the soil around the plants with rotted farmyard manure or garden compost three weeks after planting, drenching it with water afterwards. Another method is to work a top dressing of a nitrogenous fertilizer, such as sulphate of ammonia or nitro-chalk, into the soil around the plants with a hoe at the rate of 15-30 g per sq m (1/2-1 oz per sq yd) and 30 g per sq m (1oz per sq yd) respectively, again followed by a generous watering. This should be done five weeks after planting. When the curds have just started to form, give a top dressing of nitrate of soda at the rate of 30 g per sq m (1 oz per sq yd).

Winter cauliflowers have the hazard of too much water to contend with in winter, as well as that of too little during the summer. Many market gardeners earth-up round the plants in early to mid-autumn, forming continuous low ridges. This ensures that excess water drains away from the stem. It also helps firm the plants against strong winter winds. If the winter has been severe, it is a good idea to give the plants nitrate of potash, at the rate of 15 g per sq m (1/2 oz per sq yd) in late winter or early spring, so the cauliflowers can make additional growth. It is not necessary to feed winter cauliflower during the early part of their life, in summer or autumn.

Cauliflowers, particularly the early varieties, are not strongly competitive plants, and should be thoroughly weeded throughout the growing period. Be careful when hoeing not to damage the roots. Heavy mulching helps supress weeds for a time.

Harvesting and aftercare 

One advantage of choosing your seed from seed catalogues instead of buying plants from nurseries is that you can make a selection of varieties which will extend your harvesting period so that it covers the whole year, even early winter. A cauliflower is ready for cutting when the upper surface of the curd is fully exposed, and the inner leaves no longer cover it. Unfortunately, cauliflowers tend to mature all at once. If the weather is warm and you leave them in the ground once they are mature, the heads expand and they become discoloured and less appetizing. To avoid this, and to lengthen the season, lift some of them before they are fully grown; they will be quite edible. Another way of extending the harvesting period is to hold back the heads by breaking the ribs of some of the large outer leaves and folding them over the curds. Alternatively, gather up the leaves and tie them together over the curd so that they cover it, using a piece of garden twine, an elastic band, or raffia. Heads treated this way can be left up to a week. It will also protect the winter kinds from frost. To keep them for two or three weeks once they are mature, lift the whole plant, including roots. Hang them upside down in a cool shed or cellar, and syringe them daily.

Cauliflowers freeze well and if you have a freezer, you can deal with an over-abundant crop by freezing the surplus for future use.

When harvesting the heads, cut in the early morning when the plant is freshest—ideally with dew on it. During frosty weather, however, it is best to wait until the warmest part of the day. Cut straight through the stalk with a very sharp knife, making sure you leave sufficient leaves around the curd to protect it.

If there is a late autumn frost which threatens to be prolonged, it is best to lift and store all plants with mature or nearly mature heads. Dig them up, with the roots, and put them on the clean floor of a cool shed or cellar. Make sure the heads are completely protected by the outer leaves, and then cover the roots completely in moist sand or soil. They will keep in this way for two to three weeks.

Unlike some brassicas, the cauliflower will not produce worthwhile shoots after its head has been cut Clear the remains of the crop as quickly as possible, either burning the surplus leaves, stems and roots, or putting them on the compost heap if they are free from pests and diseases. If you are composting them, chop up the stems and roots first.

Tips for exhibiting cauliflowers

Because of the timing of most local shows, summer cauliflowers are more often exhibited than winter ones. The best variety to grow for show purposes is

All the Year Round, because it is accommodating enough to be grown for most show dates. The exact timing of sowing for a particular show is virtually impossible, due to unforeseen changes in weather. Make a small sowing 22 weeks before the date, and make weekly sowings for the next month; this way you will be able to select the best heads, and avoid disappointment.

Although the best cauliflowers for exhibit are those which have been picked on the day, you can pick mature heads up to a week before the show and store them. Cut the roots off and strip the outer leaves; leave about 20 cm (10”) of stem. Hang the cauliflowers in a cool, dark shed. If the temperature drops below freezing, though, the curds will be damaged, and useless for exhibition work.

A few days before the show syringe the cauliflowers selected and fold over the leaves to protect them. Three heads is the usual number shown in single classes, and six heads in collections. On the morning of the show, make your final selection and cut the smaller inner leaves off, leaving the outer ones with the tough mid ribs to protect the plant. It is unlikely you will have to wash the heads, as they do not come into contact with the soil. To take them to the show, leave the outer leaves on, roughly trimmed, wrap the heads in tissue paper and put each head in a plastic bag and place close together, head to tail in a box. It is best to pack them in a single layer; fill the spaces between the heads with wood wool.

Keep the heads covered until the last moment before the show. If three heads are being shown, arrange them on a plate or in a round basket, with the heads pointing outwards. To display six heads, special triangular mounting boards are used. The heads are spiked onto 15 cm (6in) wire nails, which are evenly spaced over the board. Pack the spaces in between the heads with fresh moss and parsley sprigs. Make sure the parsley is neat, well back and close to the base, so that the depth of the heads can be seen.

The judges will look for reasonably-sized heads, 12.5-15 cm (5-6in) in diameter; they should be pure white, tightly packed with solid curds, without any staining or frothiness. Heads with brown or pink curds, usually a sign of lack of water, will not win prizes, nor will those which have irregularly shaped heads, or leaves mixed in with the curds. The process of setting up a triangular display of cauliflower heads may take up to two hours to do properly, so leave yourself plenty of time. Have a trial run, the day before the show, using second best specimens; with this experience it will be easier to set up the final exhibit.

23. June 2013 by admin
Categories: Tips and Advice, Vegetable Gardening | Tags: , , , , , | Comments Off on Guide to Growing Cauliflower | How to Grow Cauliflower


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