Growing your own cabbages is relatively easy as they are suitable for most temperate climates and soil types, and they require very little attention. They are members of the brassica family and are extremely hardy being able to withstand conditions that would kill off many other crops, they thrive in cold damp winters. They are a biennial plant grown as an annual.
Soil and Site suitability.
As already stated cabbages will do well on almost any soil type provided that it is well drained, however they do prefer a medium to light soil which will retain a reasonable amount of water.
Ideally the ground should be prepared several months in advance by applying lime and manure. If this is not done then apply a general fertilizer prior to sowing. The best site is an open sunny one that has not had any of the brassica family grown on it for at least two years, this is done to reduce the risk of disease being passed on to them.
You can sow cabbages outdoors or under glass and the method is basically the same. You will want to plan a succession of sowing from about mid spring until early summer which will give you a long harvesting period. The exact timings will depend on the variety you are growing and when you want to harvest the crop. The seed should be sown in a seed bed that has been finely raked, prepare drills that are 1.5cm (½ inch) deep and 15cm (6 inch) apart and aim for no more than 8 seeds per 30cm (12 inch).
If you require a mid to late summer crop the seed should be sown in late winter or early spring protected by cloches or in a cold frame.
Once the seedlings have four or five good cabbage like leaves transplant them to their permanent positions leaving 30-40cm (12 –15 inch) between the plants in all directions. If this is done in mid to late spring then some protection from frost may still be needed.
You must never allow the plants to dry out as this will severely check their growth so water liberally especially in hot dry weather. Keep the soil free of weeds by frequent hoeing this will also help to aerate the soil and to deter pest from laying their eggs near the crop.
Now as cabbages are greedy plants it is as well to give them applications of liquid fertilizer during the growing season but do not used those based on nitrate of soda as these will give the leaves a bitter taste. As they begin to mature some of the outer leaves may turn yellow break off these leaves as soon as you see them.
You can tell when they are ready to harvest as the heart will be firm if you give it a gentle squeeze. You may either lift the cabbage in its entirety and remove the roots at a later time or pull back the outer leaves and using a sharp knife cut the heart out just a little above the lower leaves. If you used the second method you may want to leave the stems in the ground to over winter these will then produce new shoots in the spring that can be used as spring greens.
It is possible to keep good mature cabbages that have firm hearts for several weeks after harvesting, if they are kept in a cool airy frost free shed. Do not stack them on the ground but make a rack out of wood or chicken wire that is raised of the ground.
Red cabbages are usually sown in the spring for harvesting in autumn. All red varieties are of the roundhead type and need to mature for a longer period of time than spring sown green varieties. They also in general have smaller heads than their green counterparts, and are mainly used for pickling but are also excellent if cooked simply and served hot.
Sow the seed in an outdoor seed bed in mid spring and once there are four good leaves transplant to the permanent position. Make sure you do not let the plants dry out and apply a liquid fertilizer during the growing season.
As they are not as frost hardy as the green varieties it is best to harvest them before the first frosts come, they will keep well in a cool, dry frost proof shed for several months.
Savoy cabbages are extremely hardy and have wrinkled curly leaves. In general they tend to have a milder flavour than some of the other spring sown varieties. Due to the large range of varieties of savoys it is possible to have crops ready for harvesting through out the winter and into early spring
Sow the seeds in succession from early spring until early summer in prepared outdoor seed bed with some protection from frost for the earlier sowings. The savoy seedlings should be transplanted when they are large enough to handle and spaced out at about 45cm (18 inch) apart. Again keep the soil free from weeds by frequent hoeing and keep well watered.
Like the other types savoys are harvested when they are firm hearted by lifting with a fork and then removing the roots and outer leaves. Ideally they should be used as they are harvested although some varieties will keep for a month or so after harvesting if kept in a cool dry airy shed.
Spring cabbages are sown in the summer for harvesting the following spring, and are particularly welcome as at time there is a lack of fresh vegetables in the garden and those in the shops are expensive.
The spring grown varieties unlike the others will need a bit of protection from the worst of the winter winds, so they need a more sheltered site giving some protection from the predominant winter wind in your location. Although they do like a sunny site but be careful not to provide a site that is too warm and sheltered as the plants will have a tendency to run to seed in spring rather than producing firm hearts.
Ideally the soil will be light and well drained so as to avoid water logging during the winter. If you have heavy soil you can try growing the plants on ridges will help with the water drainage. Do not grow spring cabbage on freshly manured soil as this will lead to bolting, the soil will ideally have been manured for a previous crop some months previous.
Make two sowings two weeks apart in mid to late summer, the soil should be moist, if there has been a hot dry summer water the site well about a week before sowing and then again just before sowing so that the soil is moist.
Spring cabbage can either be sown in a seedbed or in the permanent bed. Which ever you choose rake the soil to a fine tilth and created drills that are 1.5cm (½ inch) deep. In the seed bed leave 15cm (6 inch) between the rows. In the permanent bed the rows should be 45cm (18 inch) apart if you are going for hearted cabbage, or 30cm (12 inch) for spring greens. Aim for no more than 8 seeds per 30cm (12 inch).
In the permanent bed thin out the seedlings as soon as they are large enough to handling, leaving 30cm (12 inch) between the plants for spring greens and 45cm (18 inch) for hearted cabbages.
Cabbages sown in the seed bed can be transplanted when they have four or five leaves and is usually done in early to mid-autumn. Ideally aim to transplant during showery weather, if this is not possible water the plants and the permanent bed well the day before. To transplant lift the young plants with a trowel keeping plenty of soil around the roots, in the permanent bed dig a hole that is large enough to take the root ball and fill with water. Place the young plant carefully into the hole so as not to disturb the soil around the roots, then as the water is absorbed into the soil firm the ground down around the young plants
Unlike the other types, spring cabbage do not need applications of fertilizers etc. as this would cause the plants to bolt in the spring. The only time a fertilizer should be applied is if the plants have been stopped by severe winter weather when an application of quick acting nitrogenous fertilizer will give them the boost they need to produce a good crop.
Keep the bed clear of weeds by lightly hoeing several times being careful not to loosen the soil around the plants. In late autumn you will need to earth up the soil around the plants to make a continuous ridge, this will help to stabilised the plants and to drain off excess water. If you have a very exposed site you will need to provide some form of protection from late autumn through to mid spring, this is normally done with the use of cloches. Even if you have a sheltered site you will need to provide some protection from birds as they will find the green young leaves very attractive during the winter. This can be done with wire netting.
You can harvest spring cabbage at three different stage of their development. In early spring you can pull them before a head has formed, giving you young spring greens, if you do this every other plant then those plants left will have more space to mature to their full size.
The hearted plant should be ready in late spring and can be harvested by either lifting with a fork and then removing the heart, or if you are not clearing the ground for another crop you may want to cut the heart from the stem leaving the roots in the ground, these will then produce a second or even third crop of spring greens.
You should now have enough information on how to grow cabbages, to be able to grow them to get a good fresh supply the whole year round.