How to Grow Brassicas

Summary: Find out all there is to know about growing Brassicas from the best preparation techniques to all the essential growing tips you need

Brassicas are a really versatile family of vegetables, and with a little planning they can keep you fed throughout the year.

What Are Brassicas?

The leafy brassica family includes cabbages, cauliflower, kale, Brussels sprouts and broccoli. Swede, turnips and radishes are also part of the family.

Kale is a very easy member of the brassica family, so it’s a good one to start with if you’re new to brassicas. It has the added bonus that you can pick a few leaves at a time rather than having to wait for it to form a head, like a cabbage. Purple sprouting is another great vegetable to grow – it can be expensive in the shops, and it’s really nutritious as well as tasty. Brussels sprouts are fun to grow, and there’s nothing like eating your own crop for Christmas dinner!

Cabbages can be very rewarding when they grow well, and very disappointing when they don’t! It’s worth trying a couple of different varieties, as you may find you have better luck with some than others. Cauliflower are the trickiest of the lot to get right, so perhaps worth waiting until you’ve got some experience with other brassicas.


Brassicas like a bit of shade, so pick an area that won’t be in full sun all day if you can. Ideally, you should begin by digging your brassica patch over in the autumn, adding a good dose of compost or well-rotted manure to it and working it in well. Once dug, trample over it to make it nice and firm, just how brassicas like it.

Brassicas can be quite picky about the soil they grow in. They like a pH of 6.5 to 7.5, so get a soil tester and add some lime to the soil if it’s too acidic.

Growing From Seed

You might decide to buy young plants at a garden centre, but if you have a greenhouse it’s worth a go at growing your own plants from seed. Also all brassicas benefit from being started off under glass, so don’t be tempted to just sow them straight in the ground.

Sowing in modules makes it easier to transplant the plants at a later date – these are sets of small, square plantpots, joined together. Fill the modules with seed compost and water it well. Try to place just one seed in each module, so you don’t need to worry about disturbing the roots later by thinning them out. Scatter some fine compost over the top of the seeds.

Winter brassicas should be sown in spring – April is usually about the right time.

Planting Out

Once the plants reach about 8cm (3”), or 15cm (6”) for kale and Brussels sprouts, they should be ready to plant out. Make sure you give the young plants a good soak the day before you move them. Dig a hole in the soil with a trowel and pour some water into it, remove the plant from the module carefully and place it in the hole, then fill in the sides and firm it down well.

Spacing will depend on the type and variety – check the seed packet for information.

Growing Tips

These leafy plants will benefit from a couple of feeds. Use a nitrogen-rich feed once when you plant them out in June, and again in September.

Most brassicas are quite drought-hardy, but they will need watering when you first plant them out, until they are settled in and well-established.

If you don’t want your brassicas to be decimated by caterpillas, set up netting over them. Make sure the netting is high enough for taller plants like kale and purple sprouting. The netting will also stop the brids from going after young, tender plants.

Whitefly are another pest that enjoy brassicas. They are unlikely to decimate your crop, so you can choose to spray them, or just wash them off when it comes to eating the leaves.

Slugs and snails love brassica leaves, so put down pellets or set beer traps.

Rotate crops each year to avoid diseases. There are a large number of diseases that can affect brassicas, from club root to wet rot. If any plants do become infected, remove and destroy them. Making sure the ground is limed and well-drained will help to combat these diseases.

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