Start your soil preparation November to December, this is the best time to prepare the ground for cauliflowers. Add a barrow full of rotted, two year old manure or compost, per square metre and dig well into top 25cm (10”) of soil. Leave to over winter. In mid-March or early April lightly rotovate or breakdown with a three pronged cultivator or rake. If required lime the soil early to mid-April. Test the soil for pH at five different places where you are growing your cauliflowers. Dig down 10 to 15cm (4-6”) deep and pool all five lots together. When testing pH this will give you an average. The lime to use is carbonate of lime. There are different ways of taking pH tests, the best is to send it away to a laboratory or to do it yourself with the kits that are available. For every point on the pH scale, for example to raise pH from 6 to 7, (seven being neutral) you should add 1lb (450g) of lime per square metre. Lightly rake into the top 15cm (6”).
The correct fertiliser to use should contain a high nitrogen level, the NPK ratio being 25, 15, 15. This is best applied approximately 10 days before planting the cauliflower out and is lightly raked into the top 10 to 15cm of soil.
Variety of Cauliflower
Early cauliflower’s: Beauty F1, Memphis F1 and Sergeant F1 or mid to late season use Virgin F1, which is banker. It is advisable to grow a few Lateman but this is not an F1 Hybrid but is well worth growing. There are others available Ice Burg F1, Liberty F1 and Minneapolis F1 and all male sterile strains from France. Most of the early varieties of cauliflower take approximately 13 to 15 weeks (such as Virgin, Memphis and Liberty).
When sowing seed, sow in a peat based compost in modules, put the seed in, lightly cover, water, tag and date; half fill a standard seed tray with compost and put the module tray on top. The reason for this is, when the seeds germinate and the roots go down it makes a good root structure when pulling the plugs out to pot on. Please note, never put cauliflower seed on any bottom heat, when the green house temperature rises above 70% move your seed trays under the benching out of direct sunlight the reason being that all cauliflower seed prefers to be germinated at 50° to 55°.
When the seedlings in the plug get big enough to handle (2 true leaves), pot on in 7cm (3”) pots of John Innes No. 2 mix when the seedlings roots have filled the pots. Pot on again in a 10cm (4”) pot of John Innes No. 2. All the plants should be well hardened off well before planting out.
The spacing given to early cauliflower is 40cm (16”) between each plant and 61-180cm (2ft – 6ft) between each row. Mid and late season cauliflower require 51cm between each plant and 61 – 81cm between each row, the reason being Virgin etc are bigger and need that bit of extra space. When planting out, dig a hole 10 to 15cm (4 – 6”) deep put 1 heaped tablespoon of lime in the hole, put the plant in, dust the root with a chemical to protect from cabbage root fly, fill in and scatter another tablespoon of lime round each plant. This helps to keep the growing area neutral and helps control club root if you have it in your ground. Keep up a rigorous spraying program, every 14 days if possible, using alternative insecticides and fungicides. Scatter slug pellets every so often round the plants. Water when necessary, when the cauliflower starts to bulk and starts to get a curd approximately 10cm (4”) round increase the watering to every other day and give half gallon per plant. When the cauliflower’s are mature tie the tops up with string or twine, in order to keep the curd shaded and as white as possible.
Heads that have solid white curds. Also free from pests and other damage, a good specimen should be no more than 200mm (approximately 8”) in diameter. The curd should form a perfect circle when viewed from above. The curd should have a medium dome shape when viewed from the side with the foliage neatly trimmed and root stems pruned to 76mm (approximately 3”).