- Sow; February-May, October-December
- Plant; May-July
- Harvest; February-May, October-December
Cauliflowers have a reputation for being tricky to grow, but with the right growing conditions and care, you can successfully grow cauliflower to rival any you can buy in the shops. What’s more, you’ll find a huge variety to grow, including the alien-looking green romanesco cauliflower.
How to grow cauliflower
Plant cauliflowers in rich, heavy soil with plenty of moisture. Prepare the soil well and add plenty of organic matter such as well-rotted horse manure or compost. Firm them in well to prevent cabbage root fly laying eggs in the soil around the stem, and use a root collar if necessary. Feed fortnightly with nitrogen-rich liquid food and harvest between three and five months after sowing.
Growing cauliflower from seed
Cauliflowers can be sown direct in a seedbed although results tend to be better from sowings made in seed trays and then planted out later. Sow from February under glass or March direct. You can also make later sowings under glass from October, and overwinter the plants for an early harvest the following year.
To sow direct, sow thinly, 2cm deep in a well-prepared bed, free of weeds. Thin seedlings to 60cm.
To sow under glass, fill a multi-celled tray with moist, peat-free seed or multi-purpose compost and sow seeds 2cm deep. Thin seedlings to one per cell and wait until all risk of frost has passed before gradually acclimatising plants to outside conditions before planting out.
How to plant out cauliflowers
Cauliflowers do best in a sunny spot with rich, moist, alkaline soil incorporated with plenty of organic matter such as well-rotted horse manure or garden compost. If you think your soil may be acidic then do a pH test and add lime if necessary – not only will the plants grow better but it’s also thought this can prevent the fungal disease club root. The best month to plant cauliflower is either May, June or July.
Plant out young plants you have grown from seed or mail-ordered plug plants that have been potted on and acclimatised to outdoor growing conditions.
Plant deeply, spacing summer and autumn cropping varieties at 60cm, and winter varieties at 75cm. Reduced spacings of 30-45cm apart will result in ‘mini’ cauliflowers suitable for one person. You can expect to grow one cauliflower head per plant.
Ensure the soil is moist before planting – dry soil could lead to a check in growth which can cause cauliflowers to bolt or bear deformed heads. Firm soil around the plants and water thoroughly. Add a collar to prevent cabbage fly if needed.
How to care for cauliflowers
Water every 10 days to two weeks, more frequently in dry weather. Hoe around the base of plants to reduce competition from weeds. Once the plants are established, start feeding with a high nitrogen feeder to boost growth and aid the formation of curds.
Growing cauliflowers: problem solving
Protect plants from pigeons and the caterpillars of small and large white butterflies, known as ‘cabbage whites’. Cover plants with a fine mesh netting to deter caterpillars, and string up some old CDs to deter birds. If you do find eggs or caterpillars on your cauliflower plants, transfer them to nasturtium leaves, which they also eat. This will enable them to continue to complete their lifecycle without harming your cauliflower plants.
Clubroot is a fungal disease, affecting the roots of cauliflowers and other brassicas, including Brussels sprouts, cabbages, turnip and swede. Roots become swollen and distorted and overall growth can be stunted. It’s difficult to completely remove from soil, but there are plenty of ways to prevent it.
How to harvest cauliflowers
Cauliflowers typically take three to five months to mature, depending on when you sowed the seed. Bear in mind that it can be tricky to know when to harvest your cauliflower at first – check the seed packet for the ideal harvesting size (this can vary by variety) and ensure there’s a good, firm head – you’ll have missed the harvesting window once the head has started to separate. White varieties should be harvested before the head turns yellow.
To harvest cauliflower, cut the stem with a knife or good pair of secateurs, taking the whole head and a few of the leaves beneath it.
Advice on buying cauliflower
- Make sure you have the right conditions for growing cauliflower, including a rich, alkaline and moist soil
- If buying plug plants, pot them on individually and water well before planting
Cauliflower varieties to try
Cauliflower ‘All Year Round’ – popular for summer and autumn harvesting. Compact habit with white, tight heads.
Cauliflower ‘Walcheren Winter Pilgrim’ – winter hardy, bearing creamy white, compact heads.
Cauliflower ‘Depurple’ – unusual variety with purple heads and a sweet taste.
Cauliflower Romanesco precoce – whirling green spirals high in antioxidants.
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