Course extract from Organic Kitchen Gardening

Study book Five

Vegetables

5.1 Introduction to study book 5

The next three study books will deal with propagation methods, cultivation, pests and diseases as they apply to a wide range of plants.

5.2 Vegetables

Brassicas

This is a group of vegetables that as a rule do quite well in the British Isles. Many are quite large, leafy plants which, as you would expect, need the ample rainfall we usually complain about and can generally cope quite well with cold northern winters.

The cabbage is the 'chief of the tribe' here and there is a very wide range of types able to be grown to mature in different seasons and so provide a succession of crops for the table all the year round. As with many other vegetables, the introduction of the F1 hybrid cultivars greatly increased the vigour, uniformity and reliability of the various types - remember, however, that saved seed will not breed true to type - which has also increased their popularity among market growers.

Cauliflowers too, can be grown throughout the year by selecting from the various cultivars of summer cauliflowers and heading broccoli and, although the kales, sprouting broccoli, calabrese and Brussels sprouts are still seasonal vegetables, the period of maturity can be quite extensive if advantage is taken of the 'early', 'mid' and 'late' maturing cultivars available.

Brassicas have a very important place in vegetable garden or field rotations (see study book 4 ~ intro.), but are equally suited to growing as individual crops in plots, raised beds or, increasingly in the small garden, in containers.

The most important thing to remember here is that members of the family Cruciferae must not follow each other year on year since they are all susceptible to the same type of pests and diseases.

They do best on a rich, fertile soil, manured for the previous crop e.g. potatoes, or in the year of planting and, although this is particularly important for Brussels sprouts and especially so for cauliflowers, one needs to be careful not to provide too much nitrogen which tend to make the plants 'flabby' and less able to cope well with low winter temperatures.

A firm, but not compacted, soil is required and liming may be necessary to provide a pH of at least 6.6 if club root problems are to be avoided.

Brassicas are usually raised in outdoor seedbeds and then transplanted to their final positions ~ except plain-leaved kale, which is best sown directly and thinned as required. The seed bed needs to be fertile to give the seedlings a good start and it must be firm; after sowing in shallow drills and lightly covering the seeds, the soil should be well firmed with the head of a rake. Do not forget to label the rows clearly ~ the seedlings look notoriously similar at first!

When transplanting, hold the seedling by a leaf and not the stem, handling as little as possible to avoid damaging the delicate root system.

Cabbages should be lowered very carefully into the prepared hole so that the lowest leaves are at soil level but cauliflowers should be planted no lower than they were in the seed bed. It is very important to firm the seedlings in well with the hands and then water well.

As with all transplanting, early evening is the best time but, whatever the time of day, strong sunlight must be avoided and, if possible, windy weather which will increase transpiration rates and put a big strain on the 'in shock' plantlet.

Brassica seeds are usually sown at a depth of around 1 cm in rows some 15 cm apart. They are then thinned ~ according to cultivar ~ to around 8 cm and 10 cm. When thinning, place a finger and thumb on the soil close to the base of the seedling that is to stay to avoid disturbing the roots as the rejects are pulled out.

Transplanting is usually carried out, at a favourable time, when there are around 4-6 true leaves - about six weeks after sowing - with final spacings of 30 cm (some cabbages), 45 cm or more (cauliflowers) or, as much as 75 cm (some sprouts). Advice from seed suppliers (usually on the packet), the growing system and your own experience will dictate the appropriate spacings of both rows and plants within the rows

Some cultivars of cabbage and cauliflowers that mature during June and July are often started under glass and transplanted out ~ after hardening off ~ in March or April. The pointed cabbage 'Pyramid', shown above, is a suitable example that can be sown early under glass in early February and has the added advantage that it can be grown either as spring greens or as a heading cabbage. Spacings, of course, must be adjusted accordingly and in this particular case 15 cm x 15 cm (6' x 6') would be appropriate for greens while a smaller heading cabbage of this type will require some 40 cm x 25 cm (15" x 10" to 12') in normal circumstances.

Among the most commonly grown garden brassicas are:

Brussels sprouts (Brassica oleracea Gemmifera group),

Broccoli (Brassica oleracea Italica group),

Cabbages (Brassica oleracea Capitata group),

Calabrese (Brassica oleracea Capitata group),

Cauliflowers (Brassica oleracea Botrytis group)

and Kale (Brassica oleracea Acephala group).

Overleaf is a table showing the different species available to the gardener - all members of the Cruciferae family - and the appropriate seasons of sowing and use.

__________________________

Back to Course Summary

Back to ‘Our Courses’