Cabbages, like all the plants in the Brassica family are descended from the Wild Mustard plant and their domestication has led to them resembling nothing much like their naturally-evolved relatives. In fact, they have been interfered with in so many ways that, just like domesticated pets, they would find it difficult, indeed practically impossible to survive in the wild. As a result, they require quite a bit more care and attention than most plants. They certainly can be a challenge to grow but that makes it all the more satisfying if you can manage to produce a perfect specimen.
Pampered pets they may well be but they are worth the effort since they will reward you with a big boost of nutrition. Cabbage is an excellent source of vitamin K, vitamin C, vitamin B6 and dietary fibre although it does have a well-deserved reputation for increasing intestinal gas! Despite that, it is good for you and has even been linked to protecting against cancer and other diseases.
Sowing the seeds
Because it is a cool season vegetable, cabbage likes to take a break during the hotter months of summer. Summer-harvested cabbages are started off indoors quite early on. Mid-February to mid-March is the best time. By the time the seedlings are about six weeks old, they should be ready to be hardened off before being planted outside.
Soil and growing position
Remember that cabbages are not born survivors. They need special care and that care starts with ensuring they have a good amount of nutrition. Deep soil, rich in organic matter and natural nutrients suits cabbages best. In a crop rotation plan, they should follow the legumes (beans, peas, etc.) since the legumes will have left behind plenty of nitrogen to support the densely packed leaves that make up the cabbage head. If the soil is acidic, then you have to add some garden lime since cabbages really do need a neutral soil.
Even though they are a cool-season crop, they prefer a growing position in full sun and they should never be left short of water otherwise they may try to flower before they have completed that lovely tight head that you are looking for.
Apart from that, the main concern you have when growing cabbages is to protect them from pests and diseases.
Pests and diseases
Because they have been so heavily domesticated, cabbages possess no real defence strategies of their own and it seems there are many pests and diseases that are more than happy to exploit this. This is the main challenge attached to growing cabbages or any other brassica.
Let's begin with the fungal infections - downy mildew, blackleg, softrot, black spot, powdery mildew and clubroot. With the exception of clubroot, these infections are caused by either cool, wet or warm, wet conditions. There is really no treatment once the plants are affected so prevention is best by applying good plant husbandry. Even though you need to water the plants little and often, you should ensure they are located in a free-draining soil so that they are never sitting in water. Allow good air circulation amongst the plants as well. For clubroot,which is soil-borne, you should not grow members of the cabbage family in any soil that is affected by it for a number of years. Liming the soil to bring up the pH can help guard against the fungal spores multiplying.
Now, onto the pests.....
The ever-present aphid species attacks cabbages but they're small fry compared to some of the others pests that cabbage plants might encounter. Spray aphids with insecticidal soap or, because cabbages have good thick leaves and form fairly sturdy plants, you could just knock the aphids off regularly with a strong jet of water.
Pigeons are a real pest on allotments especially and they seem to have a liking for cabbage. You can tell if pigeons have been having a go because there will be nothing much left of your cabbage plants except for the thick midribs. If you see a skeleton of cabbage ribs and nothing else, suspect pigeons. Netting should keep the pigeons away but make sure the netting is completely secure as you don't want to trap the pigeons or other birds inside the netting.
Caterpillars do the most damage to cabbages. The densely packed leaves that form the heads are a great place for the small white butterfly, the large white butterfly and the cabbage moth to lay their eggs. When these eggs hatch, the caterpillars will munch relentlessly on the leaves rendering the plant just about uneatable in a matter of days. A good insect netting should prevent butterflies and moths from getting to your plants in the first place but, just as with netting for pigeons, make sure the netting is completely secure all the way round. Companion planting for these pests can also be useful.
Good companion planting requires a multi-pronged approach and this is most important when it comes to cabbages. There are four things you should consider; interrupt the scent locators of flying insects; hide your plants; put off egg-layers altogether and prevent fungal infection.
When a flying insect thinks it has found a cabbage leaf, it lands on the leaf but does not immediately lay its eggs. To ensure it hasn't encountered a single leaf that has fallen off or been removed from a plant, it makes a small number of short test flights. If it lands on another cabbage during these test flights, it knows it has found more than one plant and that its offspring will be well fed when they hatch. If you can plant beneficial plants in between your cabbages, you might confuse butterflies and moths to such an extent that they will fly off without laying eggs.
You begin by hiding the cabbages both visually and by masking their scent. Planting cabbage plants in a nice straight row with nothing else in between is like putting up a big bulls-eye for butterflies and moths to see. Interplanting with strong-smelling plants that also have anti-fungal and anti-bacterial qualities such as chives or garlic will have double benefits. Surround your cabbage patch with a wall of lavender as well to drive the message home. Growing nasturtiums a few feet away from your cabbages will attract aphids away from your cabbages. Growing pot marigolds amongst cabbages has been shown to reduce the amount of eggs that butterflies and moths can lay.
Harvesting and storage
Harvest summer cabbages as soon as you think the heads are large enough. Remember, cabbages don't like it hot so you can't leave summer cabbages on the plant for as long as the winter types.
Cabbages can be stored in the fridge for up to two months. Don't remove the leaves and don't wash them before you put them in the fridge. Inside a plastic bag, they should retain enough moisture to prevent them from drying out too fast.
To freeze cabbage, blanch it in boiling water for a couple of minutes, then plunge into ice cold water before draining thoroughly and bagging them up for the freezer.
Summer cabbage varieties
The best summer varieties are pointed. Pointed white cabbages to try are 'Greyhound' and'Hispi'. 'Kalipos' is a decent pointed red cabbage and 'Drummond', a red variety with a rounded head. For a rounded white cabbage that you can pick in June, try 'Unicorn'.