UK crop guide
Cabbage is four crops that share a method. The RHS times them like this: summer types sown from late winter to mid-spring, autumn types from mid-spring to early summer, winter types in late spring or early summer, and spring cabbage in July for heads the following year.
Outdoor sowings line up as February to April for summer cabbage, April to June for autumn and winter cabbage, and July for spring cabbage. Plants take about four to six months. A mix of types is how you cut cabbage all year.
Modules give you a cleaner start, out of reach of slugs, and they can reduce the effect of club root because the plants are already growing before they meet garden soil. Sow two seeds per cell, about 1cm deep, and thin to one. Sowing time still depends on the type, from late winter through summer.
Plant out when the plants are 10 to 15cm tall, with five or six true leaves, usually about five weeks from a module sowing. Harden off anything that has been on a windowsill.
Cabbages are often sown in a seedbed and moved later, because they sit for a long time at their final wide spacing. You can also sow them where they will stay. Outdoor drills are about 2cm deep.
February to April is for summer cabbage, with cover on the early sowings. April to June covers autumn and winter types. July is spring cabbage. In a seedbed, aim for seedlings about 10cm apart, then transplant. In the final row, sow three seeds at each station, 30 to 45cm apart, and thin to one.
Spring cabbage is sown in July and overwintered. Space those plants about 10cm apart at first, then thin in late February or March to 30cm. Eat the thinnings as spring greens.
Water the day before you move them, and plant firmly into ground that was manured the previous autumn if you can. Cabbages like rich, firm soil, and they should not follow other brassicas. If the soil is very acid, lime it the winter before to raise the pH above 6, which also discourages club root.
Compact varieties can sit 30cm apart. Large autumn and winter heads need up to 45cm. Cover the bed with insect-proof mesh on hoops. It keeps off caterpillars, cabbage root fly, whitefly and pigeons.
Cut when the head is firm and the size you want. Taking every other plant first lets the rest grow on. Spring and summer stumps, scored with a cross about 1cm deep, often throw a smaller second head. Dig the finished stump out rather than leaving it to harbour disease.
Winter cabbages, including Savoys, stand in the garden for months once they are mature, or they can be stored somewhere cool, dry and frost-free. Spring cabbage is the April to June crop from a July sowing, picked either as greens or as a heart.
Pigeons strip leaves back to the midrib. Cabbage white caterpillars do the same from the inside of the plant. A proper mesh cover, held off the leaves, is the RHS approach from planting onwards. Check inside the cover now and then.
Swollen, distorted roots and a plant that wilts in mild weather can be club root, a long-lived soil disease. Do not replant brassicas in that spot. Lime acid soil the winter before, choose a resistant variety, and consider modules or a large pot of fresh compost so the young plant is not in infected ground from day one.
Seedlings in a seedbed disappear overnight. Module sowing avoids the worst of it. Once plants are outside, they still need protection until the stems toughen.
Kit for this crop, based on the method above.
A fine compost for modules and small pots. The RHS recommends peat-free mixes.
For crops started under cover. Deep pots suit peas, beans and sweetcorn.
The RHS found a full cover is the most effective defence against carrot fly, and it also keeps pigeons and caterpillars off brassicas.
For early sowings and for covering tender plants if a late frost is forecast.
Dug or mulched in before planting. Do not use fresh manure.
Variety and sowing date, so succession sowings do not get mixed up.
In July. The plants overwinter and are eaten as spring greens or as hearts from mid-spring into mid-summer. Thin them to about 30cm in late February or March.
A compact variety can. The RHS suggests one plant in a 30cm pot, or up to three in a 50cm pot, in peat-free compost. They still need mesh if caterpillars and pigeons can reach them. Growing bags are not suitable.