How to Grow Cabbage

Botanical Name: Brassica oleracea

Plant Type: Hardy Biennial

Cultivated for more than 1,000 years, cabbage is not only one of the best yielding leaf crops there is, but cabbage also has the best storage life of any leaf crop – and that’s even without fermenting it! There are many different varieties available to suit varying cuisines, a range of harvest times as well as nutritional profiles. Rich in folates, cabbage is a must for mothers-to-be; and when mixed with caraway or fennel seed, the ‘windy’ side effects often associated with cabbage consumption are greatly reduced. Preserved as Sauerkraut (fermented cabbage), the nutritional benefits of cabbage have once again been noted and celebrated but let’s not forget our favourite use: coleslaw and baby wombok salads.

The cabbage itself, in its modern form, is known to have been around for at least 1000 years and was developed into a number of types in Germany and Italy. The modern cabbage is a biennial, that is, a plant taking two seasons to grow from seed until it produces seed. A large, compact head produced over the first summer helps to store energy for seed production the following summer. No doubt the importance of the cabbage is due to the extended period over the autumn, winter, and spring seasons when the heads can be harvested.

Varieties

As can be expected from such an important staple crop, there have been a huge number of varieties developed over the years. Two methods of classification are used to group cabbages, which are based either on the season during which they are harvested, determined by their maturation characteristics, or according to their appearance.

Spring cabbages are slow-growing types that are sown or transplanted during mid-summer for harvest the following spring.

Summer cabbages are rapid growing types that are sown in spring for a late summer harvest.

Winter cabbages are intermediate in their growth, are sown in spring, and can be harvested from late autumn through to the following spring.

Groups of cabbages based on appearance include:

• Savoy - crinkled or blistered leaves
• Drumhead - very compact, round heads composed of smooth leaves
• Pointed cabbage - conical-shaped heads.

A further distinction is made through their colour: Green, red, blue, and purple.

More recently, a popular trend towards growing miniature vegetables has resulted in the classification of some types of cabbage as ‘mini’.

A combination of these descriptions can also be used to describe a variety.

The summer varieties offer the advantage of producing the fastest crop but have proved a bit tricky in our trials because they have sometimes bolted and flowered in early summer in particularly hot seasons. Therefore, they offer a fast crop, but often a short season for harvest.

Spring types have the disadvantage of a long growing period and are also prone to bolting in a hot, unseasonal spring.

If you can grow only one variety of cabbage, we recommend selecting winter types, because in our trials they offer the longest season for harvest, being able to be harvested when heads are small in autumn, to maximum size in early spring.

Growing From Seed

Sow: in punnets, raise as seedlings for transplanting.

Ease of Germination: Easy

Germination Temperature: 5-21 degrees C

Germination Time: 1-6 weeks

Spacing: Transplant 40-60cm apart

Harvest: 50-164 days

Yield: 1-6kg

Cabbage seed germinates over a very wide temperature range, down to as low as 5°C, though at this temperature, germination will take six weeks. Between 18-21°C, germination will take place in less than a week. Seedlings transplant very easily and love nutrients, so place a quantity of well decomposed manure at the base of the hole before transplant.

The correct time for sowing and transplanting is largely dependent upon the maturation time of the individual variety and the gardener’s desired season for harvest. In the cooler regions, sowing or transplantation can take place from mid spring to mid-autumn. Of course, as the temperatures fall, the time to maturity lengthens, so with experience gained through staggered sowings throughout the year, gardeners can eventually develop a schedule for virtually year-round cabbage production for their particular locality.

Maintenance and Additional Care

Cabbage will grow in sun or partial shade and needs rich soil with plenty of well-rotted compost dug in and some lime for a pH of about 7.5. Once established, cabbage enjoys regular applications of organic fertilizers rich in nitrogen to boost growth; the various fish and seaweed types are well suited for this purpose. Diluted liquid fertilizers applied as a foliar spray are also beneficial and can be a useful source of boron and molybdenum to compensate for soil deficiencies.

Cabbage heads are prone to splitting and consequently rotting following heavy rain during a dry spell, because of the sudden influx of water. A constant supply of moisture tends to prevent splitting and promote uniform growth. Water regularly- cabbage roots grow at a fairly shallow level, but it’s important to keep the soil moist so your vegetables will be juicy and sweet. Add a thick mulch of organic matter around the base of the plants to help conserve moisture, insulate the roots and suppress weed growth

Cultivation

The best tasting cabbages are produced by growing quickly. Fertilize regularly and sow or transplant new seedlings each month to stagger your harvest.

Net to protect from pests such as cabbage moth and cabbage white butterfly.

Space plants according to their final size, with larger headed varieties spaced at 60cm, and small or mini varieties as close as 30-40cm.

Cabbages need regular, consistent moisture during the growing season to avoid splitting. Mulch will help to maintain constant soil moisture, but regular watering is essential. Do not water the foliage, just the soil.

If the stems grow tall, you can hill soil around the base to keep them firmly anchored and protected from the wind and accidental breakage.

Sun: Full sun

Pollination: Insect, Cross-pollination

Soil: More than any other vegetable, the cabbage enjoys rich soil, high in nutrients, so building up the organic content of the soil with manure is a necessity for best results. Cabbage can use huge amounts of nitrogen and potassium and these nutrients must be incorporated prior to planting. The soil should show good structure and be well-drained to assist in the prevention of a number of fungal diseases; we strongly recommend hilling up beds to improve drainage.

Brassicas, in general, exhibit a few disorders in soils low in boron and molybdenum, lack of the latter producing a condition known as whiptail, where the growing point fails to develop into a head. They are a little sensitive to acidic soil with a pH less than 6.0, and these conditions exacerbate boron and molybdenum deficiencies, so if there is any doubt, apply lime.

Companion Planting

Good companions: Beans, beetroot, capsicum, celery, chamomile, chilli, coriander, cucumber, dill, geranium, hyssop, marigold, mint, nasturtium, onion, oregano, potato, rosemary, sage, silverbeet, spinach, tansy, thyme, wormwood.

Bad companions: Garlic, grapes, strawberry, tomato.

Pests and Diseases

Snails and slugs enjoy munching on cabbage and aphids will often infest cabbage that are weak and vulnerable. They will also need protection from white cabbage moth

Downy mildew and a range of bacterial and fungal leaf spots can also occur in humid, wet. When dealing with soil-borne fungal diseases, crop rotation is the most effective organic method to prevent their build-up.

Container Gardening

Cabbages can be easily grown in pots and containers, but it is best to grow a single plant in each pot to avoid overcrowding. Use a premium potting mix for vegetables and water regularly. A wicking bed or self-watering pot would also be ideal to maintain consistent moisture in your potting medium.  Grow in full sun and space plants accordingly as the leaves grow.

Harvesting

When harvesting cabbage heads, cut the stem a few centimetres above the ground in an effort to encourage another smaller crop. Many varieties will resprout, producing a bonus crop of a miniature cabbage!

Seed Saving

Seed longevity: 4 years

Isolation Distance: 800m

How To Save Seed: All members of the Brassica oleracea will readily cross-pollinate, so if saving seed, isolation distances are vital. Biennials, seed will set in the second year, ripening from the base of the flower upward. Don’t be tempted to harvest too early – while you may lose some of the earliest seed, it needs to brown off before harvesting. Harvest the entire plant and hang upside down over a large tub to capture the seed as it ripens and dries. Once dry, using gloves, rub the stems from bottom to top (as if warming your hands) and sieve the contents. The seed will readily separate from the chaff.  Store in a cool, dry location.

Tips and Tricks for Success

• rotate cabbage crops every three years to reduce soil borne disease
• as plants reach maturity, cut back on watering to avoid splitting heads
• grow nasturtiums close by as a sacrificial crop, also known as a trap crop- caterpillars prefer nasturtiums, so they’ll be more likely to eat these instead of your cabbages.
• through growing a range of varieties from each seasonal grouping, it is possible in most climates to have cabbage available for the dining room table on a year-round basis
• plant stress from irregular watering or high temperatures at the 5 to 6 leaf stage will cause premature bolting. If cabbage moths are a problem, grow through autumn–spring when most pests are dormant.