How to grow cauliflowers

Cauliflowers form large-leaved plants with a single head (curd) in the centre, which is the immature flower cluster, harvested while still in tight bud. Although traditionally white, you can also grow orange, green or purple varieties, as well as handy mini caulis. You can use your home-grown harvests in soups, curries and classic cauliflower cheese. You can also grate them to make low-carb ‘cauliflower rice’, and enjoy the crunchy raw florets in salads or with dips.

The head of a cauliflower is made up of tightly packed, immature flower buds

Moving a plant from one growing position to another, often from a pot to its final spot in the garden.

transplanted

There are lots of cauliflower varieties to choose from, traditionally grouped according to harvesting time, with faster-growing and generally less hardy varieties for summer and autumn crops, and slower-growing, hardier varieties for harvesting in late winter and spring. Newer varieties often have an extended sowing and cropping period, so may overlap these traditional groupings: 

• Early-summer varieties – these are usually sown indoors in winter, then planted out in spring under cloches. They grow quickly and are ready to harvest in early summer
• Summer/autumn varieties – these are popular types. Sown from early spring indoors, or outdoors from mid- to late spring. They’re ready to harvest from late July to October, and sometimes into November, although they should be harvested before the first frost
• Winter/spring varieties – these are sown indoors or outdoors from late spring to early summer. They are slow growing, taking six months or more to mature, and form large heads, potentially up to 30cm (1ft) wide. They need wide spacing and can take up quite a lot of room over a long period. Most modern varieties are very hardy and can be harvested well beyond winter, into spring and even early summer

You can also choose more compact or more colourful varieties:

• Mini cauliflowers – these are mainly summer varieties, grown at closer spacing to keep them small, and harvested when they are the size of a tennis-ball. They are ideal if space is limited or you only want small servings, and they can even be grown in containers. They are relatively quick to mature, in as little as three months, and less prone to problems
• Coloured varieties – there are several varieties with orange or purple heads, as well as romanesco types that produce a green head with peaked florets. These are mainly summer/autumn varieties

Bring extra colour to your veg plot by growing purple or orange cauliflowers

Choose a sunny site with deep, fertile soil that is moist but free-draining. Make sure you haven’t grown cauliflowers or other brassicas in that spot for at least two years – see our guide to crop rotation.

It’s best to start preparing the soil well ahead of sowing or planting if possible. Dig in a couple of bucketfuls of well-rotted manure or garden compost per square metre/yard, ideally the autumn beforehand so the ground has time to settle, as cauliflowers like firm ground. If you add compost just before sowing or planting, firm the soil by shuffling across the surface. Remove any weeds then rake the surface level, creating a fine, crumbly texture ready for sowing/planting.

Alternatively, if you're practicing no-dig, mulch the soil with organic matter ahead of sowing or planting directly into the mulch. 

If your soil is acidic, apply lime the previous winter to raise the pH and deter club root disease  – you can carry out a simple pH test to check if this is necessary. Cauliflowers grow well in soil with a pH of about 6.5.

Cauliflower seeds are usually sown indoors, but can also be sown outdoors from mid- to late spring. The main sowing season is March to May, although you can sow in January or February indoors – or even the previous autumn – for earlier harvests. As cauliflowers tend to mature in a rush, avoid raising too many plants at a time, as they don’t store well. Sowing several small batches about three weeks apart will spread out your harvests.

Young cauliflower plants – either growing in a seedbed, raised from seed indoors or bought as plug plants – should be moved to their final growing site when 10–15cm (4–6in) tall, at about six weeks old. Indoor-raised plants must be hardened off before transplanting, to gradually acclimatise them to outdoor conditions.

Choose a suitable site and prepare it carefully, ideally well ahead of planting – see Preparing the ground, above. It’s important to give cauliflowers plenty of space, especially larger winter varieties. Wide spacing helps them grow bigger and keeps them healthier by allowing good air circulation and preventing any shading. Mini cauliflowers are the exception and are planted closer to restrict their growth. Use the following spacings: 

• Summer/autumn varieties – 45–60cm (18–24in) between plants, 60cm (24in) between rows 

• Winter/spring varieties – 70cm (28in) between plants, 70cm (28in) between rows

• Mini caulis – 15cm (6in) between plants, 15cm (6in) between rows

Water your young cauliflower plants ahead of moving them, then carefully lift them from the seedbed or remove them from their modular tray, trying not to disturb the roots. Set them in their new planting holes more deeply than before, with the lowest leaves at the soil surface, so they root in deeply. Backfill with soil, firm in and water well.

Planting in containers

Mini caulis can also be grown in large, deep pots – plant up to four in a 40cm (16in) diameter container filled with peat-free multi-purpose compost. Position them deeply, with their lowest leaves at the surface of the compost, and water well. Stand the container in a bright, sheltered spot, and continue watering whenever necessary to prevent the compost drying out, especially in summer.

Use a sharp knife to cut the stem below the head, taking several leaves too

Cauliflowers are best eaten fresh, but can be stored in a fridge for several days – they keep better with a few leaves intact. Cauliflower florets can also be blanched then frozen.  

Cauliflowers have a reputation for being tricky to grow successfully, but they should be fine if you take care to provide the right growing conditions – firm, fertile soil and consistent moisture. If not, you may encounter the following issues:  

• Deformed or button heads or bolting (premature flowering) – these can be caused by various conditions that lead to a check in growth, including root disturbance due to transplanting too late, loose soil, irregular or insufficient water, cold temperatures in spring and/or hot weather in summer 

• Discoloured heads – protect the developing curds from sun and frost, which can turn them yellow or brown, by folding the leaves over the head and tying in place with string if necessary

Cauliflower plants can also be damaged by various brassica-loving creatures, and are susceptible to several brassica diseases – for prevention tactics and more details, see Common problems, below.