Growth habits and planting needs
Cabbage is a hardy annual cool-weather crop that is easy to grow and is an important vegetable, protective against cancer and for lowering cholesterol when cooked for a short time or eaten raw.
In fact, the humble cabbage is one of the oldest known vegetables and was known to the Ancient Greeks and Romans.
If your garden is small you can still grow small varieties like the mini Sugarloaf shown above. As cabbages require a large space to grow optimally it is important to select the variety suited to the space available.
A mature cabbage in optimal conditions can grow to 30 cm tall with a spread of 60 cm. A cabbage of this size, with all its leaves, can have a transpiring area of 10 sq m. (Weaver and Bruner). This is why cabbages need adequate water throughout its growth and why mulching is so important for the optimal development of the cabbage. It more quickly uses water than other garden crops, especially in the first 30 cm where its roots are most abundant and especially when the head is forming. It will suffer greatly if watering is inconsistent and the leaves will quickly yellow. So make consistent watering a first priority when growing cabbages making sure they have have plentiful and consistent watering.
The following diagram shows the mature cabbage root system with the grid in feet.
Select a position that is in full sun with lots of air.
Preparation of the soil is also vital to grow large cabbages with a well formed heads and tender leaves. The root system needs a light, friable, well aerated soil that is rich in aged compost and well rotted chicken manure to a depth of at least 30 cm with a pH between 6.0 and 6.5. The plants also require nitrogen and potassium and should follow nitrogen fixing legumes in the crop rotation system.
Cultivate the soil around the plants only if absolutely required and only while they are small to remove any weeds. As the root system of the cabbages inter grow as the plants mature, do not cultivate around them as this will cause damage. Rather, mulch well to stop weeds growing and to conserve moisture because the root system even occupies the top 5-7 cm of the soil.
Cabbages can be sown in seedling trays 6-8 weeks before being planted out after the last frost or can be planted directly into the ground during Spring. Keep the seedling trays consistently moist but never allow the soil to become soggy. Good drainage is required throughout a cabbage’s growing life.
Cabbages, like tomatoes, survive transplantation well so they can be grown as seedlings in the greenhouse and then planted out. The most important aspect when planting out the seedlings is to make it once only and space them well apart so that they do not need to be moved again. For success choose only the strongest seedlings.
Depending on the variety, cabbages seedlings should be spaced about 30 -60 cm apart with rows spaced at 60 – 105 cm apart. Fertilize with liquid fish emulsion. Once grown the roots will occupy the whole area between the plants so thinning will not be an option. Make sure that they are well spaced from the outset.
Just before the head forms apply a side dressing of aged chicken manure to address the depletion of the nitrogen over time.
Here are some picture of different types of cabbages over their growing life.
A cabbage matures in about 60-100 days and the head should be firm to the touch.
Cut the cabbage in the morning when it is the coolest and using a sharp knife, cut it from the base of the head, keeping the closest whorl of leaves to wrap the head in.
The rest of the plant can then be removed completely and composted or if the weather still permits you can leave the base and the plant will produce small cabbage heads that you can harvest.
Store the harvested heads tightly wrapped in cling wrap in the refrigerator as soon as possible.
- Land Cress
Moths and butterflies are attracted to land cress away from your developing cabbages. Grow some near your brassica’s to protect them. The plant releases a chemical that attracts the pests to lay it s eggs on it and when the eggs hatch they eat the leaves and die.
Hyssop is another plant, a perennial, that attracts the white cabbage butterfly to itself. I t also has long spikes of blue flowers that attract bees to the garden and so is a very useful plant to grow in beds or in pots to move around where needed.