All about growing Cauliflower from seed

Growing Guide

Plan your varieites and sowing times right and you could be enjoying cauliflower all year round, in face the varieity All The Year Round is one of our bestsellers!  Typcially a slow growing crop that thrives in cool temperatures, just watch out when the heads start to form they can go from being almost harvest ready to bolting in the blink of an eye. Sow regularly for sucessional harvests, no-one needs 17 caulis ready to harvest 1 week in August!

With so many varieties, its possible to harvest Cauliflowers most of the year. There are several different types, sown and harvested at different times: 

  • Summer varieties – usually sow indoors from winter to early spring. They are fast growing and form smaller heads, ready to harvest in four or five months. They are generally easier to grow successfully than later varieties, especially if harvested before any hot, dry weather.
  • Mini-cauliflowers are mainly summer varieties, grown at closer spacing to keep them small, and harvested at tennis-ball size. They are ideal if space is limited and can even be grown in containers. They are quick to mature, in as little as three months, and less prone to problems. 
  • Autumn varieties – sow indoors or outdoors in mid- to late spring. They are slightly slower growing than summer types and bred to withstand higher summer temperatures, although light shade in the middle of the day is beneficial. They grow best in cool autumn weather and should be harvested before the first frosts.
  • Winter varieties – sow indoors or outdoors from late spring to early summer. These are slow growing, taking six months or more to mature, forming large heads. 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 through to spring.

Sow seed outdoors in April, September and October into a well prepared seedbed, for transplanting to their final positions later on. Sow at a depth of 2cm and distance of 25cm between rows. Outdoor sowings should be thinned to 7-10cm apart and once plants are 15cm tall, they can be lifted and transplanted to their final planting positions. Protect autumn sowings with a cloche or fleece to protect them through the winter.

Sow indoors from February and March at a depth of 1cm in trays of free-draining, compost and cover with a layer of vermiculite. Place in a propagator or seal container inside a plastic bag until germination. Once germinated, grow Cauliflower plants on in cooler conditions until all risk of frost has passed and plants are large enough to be transplanted with 2-3 true leaves.

Gradually acclimatise them to outdoor conditions before planting out. Gradually harden off before planting out, spacing plants 45cm apart between plants and 60cm between the rows for large curds, unless growing a mini variety like Igloo.

Top Tip

Cauliflowers tend to mature in a rush, avoid growing 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.

Cover with a protective netting or fleece to prevent attack from birds and insects. Water the plants thoroughly after planting. Feed with a nitrogen-rich liquid food every fortnight.