THE absolute key to growing good Brussels sprouts is planting them in reasonably heavy soil. 

If you’re gardening on light soil, then you’re better off buying them from the supermarket. 

The main reason for this is that it’s almost impossible to firm a light, sandy soil sufficiently around the bottom of the stems of the plants. 

Without that, the stems will rock in the wind, and the result is invariably sprouts that “blow,” instead of forming solid buttons. 

So, if there’s a part of your allotment or vegetable plot that consists of solid, hard-to-work clay, that’s your Brussels patch.

March and April are the best months to sow sprouts intended for eating at Christmas. The simplest way is to use a seedbed. 

This is a piece of ground that gets plenty of daylight in spring, though if possible it should also be sheltered from the wind, and on which the top of the earth is as finely textured as you can make it. 

Use a hoe and a rake on the soil a few weeks before sowing to achieve this open tilth — and to ensure that the seedbed is weed-free.

Sow a row of seeds thinly — that is, with space between each seed — at a depth of half an inch (13mm). 

Once the seedlings have grown large enough to be handled, remove some of them so those that remain are about 3 inches (7.5cm) apart. 

Alternatively, you can start the seeds off in trays or pots in a cold frame or greenhouse.

By early summer, when the seedlings have six or seven leaves and are 4-6 inches (10-15cm) tall, they’ll be ready for transplanting from the seedbed to their final positions. 

Most Brussels cultivars should be planted about 2 feet (60cm) apart, but check the instructions on the seed packet as some types need more space.

Before digging the seedlings up for moving, and after planting them, give them a good watering. At the time of sowing the seeds, decide where the plants are going to end up and use a garden fork to dig plenty of manure or garden compost into that patch of soil. 

Even better, choose ground which was manured the previous autumn. That way, the loosened soil will have had time to settle again.

Wind is the great enemy of sprouts, which some diners may find ironic, so try to put them in a spot where they’re not going to get the worst of the gales. 

Hammer strong stakes into the ground next to them, and as the plants grow through the rest of the summer and autumn, periodically tie their stems to their stakes. 

Mounding soil around the base of each plant, and using your boot to make it as firm as possible, is likewise an ongoing job.

You’ll almost certainly have to protect the Brussels from birds and caterpillars. The only guaranteed way to do this is to cover the whole lot with horticultural mesh, right through from transplanting to harvest.