Newcomers to vegetable gardening often have problems with growing good cauliflowers. this need not be the case. However, there are a few things to get right when trying to grow good cauliflowers.
Cauliflowers are members of the Brassica family, so need an alkaline, not acid, soil. Do a basic soil test and add garden lime to bring you ph level up to around ph7.
Firstly, make sure that you sow the right variety at the right time for your particular area: Check on this in a good seed catalogue. Secondly, you should grow your cauliflowers very steadily - don't try to rush them - and give them plenty of attention to make sure that they grow without undue stress: They do not like any kind of check to their growth.
Raise them in soil blocks - or peat pots if possible, and transplant them when they are still small - about 6 weeks old. Ensure that the young transplants are firmed well when planting - otherwise yellowing and wilting of the young plants will follow.
Cauliflowers can be sown from February through to October, then harvested from September through until the following March. A succession of sowing will give you good Cauliflowers for around seven months of the year.
Be aware that the different varieties - which will give you this seven months of Cauliflowers – will probably have different planting distances. It is not a one size fits all!
A well grown and cared-for cauliflower head
Cauliflowers need plenty of moisture throughout their growing period. This is especially so in the early stages. They need less nitrogen than most other Brassicas. Too much feeding makes them produces masses of leaves rather than curds. Keep watering throughout dry periods, or the heads can grow loose.
As the Cauliflower heads start to develop, break the leaves at the central vein and bend over onto the head. This will help to keep the heads white.
Cauliflower seedlings can be attacked by the cabbage-root fly. To deter these, you can protect the stem with a disc of foam carpet underlay. Slip this collar around the stem at soil level after planting. It should be about 150 mm (6 in) in diameter, with a slit from the outside to a small central hole as wide as the stem. You can also buy special Brassicas rings for this job.
Alternatively, dip the transplants in calomel dust before planting. This deters the cabbage fly.
As above, when planting young cauliflowers into the open ground, they must be firmed in.