Brassica family a tasty, versatile bunch
The brassicas we commonly grow in the vegetable garden include cabbages, broccoli, cauliflower, and brussels sprouts.
The Asian brassicas pak choi (bok choi), tatsoi, joi choi, sumo, mizuna and mibuna are becoming more popular here as a delicious stir fry ingredient or eaten raw in salads. Asian greens are cold tolerant and may be planted in spring or late summer or autumn for a winter crop.
All members of the family prefer a heavy soil rather than a light sandy one, with an alkaline reaction of about pH7-pH8. meaning most soils will require applications of lime or dolomite.
They should be grown in an open sunny airy position in well dug, compost enriched soils which will aid in moisture retention as brassicas in general do not like dry soils. This is especially true of cauliflower and the Asian section.
From Spring onwards brassicas can be sown on the surface of trays of seed-raising mix, just covering them and firming the soil before a thorough watering.
The seeds should germinate in between 6-10 days and can be transplanted into the garden or small containers when about 7.5 cm high. For the average family probably no more than six to eight plants at a time will be enough as they all tend to mature together. Sow every month to get a good succession of mature vegetables, or buy young plants from the nursery in six packs.
After planting they should be kept weeded and hoed, and dead and decaying leaves removed. A sharp lookout should be kept for the caterpillars of white butterflies and cabbage aphids which are grey-green with a mealy covering.
These aphids can cause considerable harm if left unchecked especially on young plants. They are usually found in colonies on the undersides of the leaves and their presence can be detected by the resultant blistering, curling and discolouration of the leaves.
A spray of insecticide, making sure that the undersides of the leaves are covered, may be necessary to get rid of them.
The other pest with which we are all too familiar, are the caterpillars of the cabbage white butterfly.
These can completely defoliate young plants and make a horrible mess of the adult leaves. Vigilance is the best defence against both of these pests and a routine inspection of the leaves will lead to early detection and damage control.
The yellow-green eggs of the cabbage white are usually laid on the underside of the leaves and can be easily spotted. On small plants they can be destroyed by wiping the leaves between thumb and forefinger which crushes the delicate eggs and small caterpillars can be dealt with in the same way.
Do this on a regular basis when the butterflies are egg laying. Serious attacks may require spraying with an insecticide or dusting with something like pyrethrum.
In recent years the health properties of brassicas has been more widely known to the public. They are rich in fibre, vitamins and minerals. They also contain phytochemicals which are believed to protect us from heart disease, diabetes and cancer. Unlike vitamins, phytochemicals are not destroyed by cooking but long boiling should be avoided, microwaving and stir-frying being more preferable.