Cauliflower Growing Calendar: Summer, Autumn and Winter Crops

Decide which crop you are growing

Cauliflower is not one crop with one calendar. Summer types are sown under cover in late winter and cut in early summer. Autumn types are sown in late spring and cut from early autumn. Overwintering types are sown in early summer, stand through the whole winter as leafy plants, and head the following spring. The plants look similar; the timetables have almost nothing in common.

Choosing the wrong one is the most expensive mistake in growing cauliflower, and it is invisible until nothing heads. An overwintering type sown in spring will simply make leaves all summer and wait for a winter that has not arrived yet.

For a first attempt, the autumn crop is much the easiest. Sowing falls in mild weather, the plants grow through the warm part of the year, and heading lands in cool autumn conditions, which is exactly when curds are at their best.

If you only grow one, grow the autumn crop. Its difficulties are the ones you can do something about, and heading falls in the season that gives the best curds.

The autumn crop, stage by stage

This is the straightforward crop and the one worth learning on. Sowing goes in as the weather warms, so there is no fight with cold germination and no buttoning risk from a cold snap. The plants build their canopy over the summer, which means water and caterpillars are the two jobs, and then head as the nights cool.

Roughly 90 to 110 days from sowing to cutting. Count backwards from when you want to be cutting and you have your sowing date.

The summer crop

A summer crop means sowing in late winter under cover and getting the plants to a decent size before they meet the cold. That is the whole difficulty: the plant must be large before the cold arrives, or the cold triggers a curd on a plant that has no canopy, and you get buttons.

So this crop is about protection rather than speed. Raise the seedlings warm and bright, pot on rather than plant into cold soil on schedule, and use a cloche or row cover over the bed for the first few weeks outdoors.

1. Sow under cover in late winter Modules on a bright windowsill or in a heated propagator at 68F (20C). Sowing outdoors at this point simply does not work.
2. Grow them on cool but never cold Aim for 59 to 68F (15 to 20C) by day and above 50F (10C) at night. Long spells below 50F on a small plant are what cause buttoning.
3. Pot on rather than plant into cold soil If the soil is not fit, move the plants into three inch (8 cm) pots. Two weeks in a bigger pot costs nothing; two weeks root-bound costs the head.
4. Harden off over a full ten days Plants raised indoors through winter are soft. Build up outdoor exposure gradually and bring them in for the first few nights.
5. Cloche the bed for the first weeks Row cover or a low tunnel over the row after planting keeps the young plants above the heading trigger and gets them established faster.
6. Aim to cut before the real heat Curds forming in warm nights go ricey. Sowing early enough that heading falls in early summer is the point of the whole exercise.

If a hard cold spell is forecast just after planting out, cover the row. A single week of cold on a six-leaf plant is enough to cost you the crop.

The winter and overwintering crop

Overwintering types are sown in early summer, planted out in midsummer, and then spend six months or more as large leafy plants doing very little before heading in late winter or spring. They occupy a bed for the best part of a year, which is the real cost, but they crop at a time of year when almost nothing else is ready.

Almost everything that goes wrong over winter is physical: plants levered loose by wind, roots sitting in saturated soil, and pigeons stripping the leaves. Prepare for those three at planting and the crop mostly looks after itself.

1. Space them wider, at 24 to 28 inches (60 to 70 cm) These plants get very large and stand for months. Crowding them means wet canopies all winter and every rot that follows.
2. Plant on a ridge or a raised bed on heavy ground Winter waterlogging kills the shallow roots. Raising the planting position four to six inches (10 to 15 cm) is often the difference between a crop and none.
3. Firm hard and earth up the stems Draw soil three or four inches (8 to 10 cm) up the stem in autumn. A plant rocked loose by winter wind fails to head in spring.
4. Stake exposed plants A cane and a soft tie on each plant in a windy site prevents the root plate being levered open, which is the commonest winter loss.
5. Net against pigeons before winter Hold netting off the leaves on hoops. Pigeons will strip a row to the midribs in a morning once other food runs short.
6. Feed once as growth restarts A nitrogen top dressing when new leaves appear in late winter drives the last of the canopy before heading. Stop as soon as the curd shows.

Do not blanch tightly in winter. Water trapped in a tied head in cold wet weather rots the curd; a light fold of leaves over the top is enough, and in weak winter sun often unnecessary.

How the timings shift with your climate

The stages above are fixed relative to each other, but where they sit in the year depends on how mild your winters are and how hot your summers get. The two constraints are that curds should form in cool weather, and that young plants should not meet a long cold spell.

Work it out for your own garden in one season by sowing the autumn crop in two batches a fortnight apart and noting which headed better. That single comparison settles your sowing window more reliably than any general advice.

Where summers are hot, the autumn crop is worth deliberately sowing later than seems natural, so that the fortnight of curd expansion falls after the worst of the heat rather than in it.

Recovering a late start

A cauliflower sown late does not simply crop late. It reaches its heading trigger at the wrong size or in the wrong weather, and you get buttons, ricey curds or nothing at all. So the answer to lateness is usually to change crop rather than to push on.

1. Two weeks late for the autumn crop Carry on, but choose a faster type of around 75 to 80 days and keep the water and feeding exactly on schedule. There is no slack left in the season.
2. A month late for the autumn crop Switch to an overwintering type and cut it the following spring, or plant the bed with a fast brassica such as calabrese instead.
3. Late for the summer crop Do not sow. A late summer sowing heads in the heat and goes ricey. Wait and put the effort into the autumn sowing instead.
4. Plants ready but the bed is not Pot them up into three inch (8 cm) pots and feed weakly. Holding a plant in a bigger pot costs nothing; holding it root-bound in a module costs the head.
5. Missed the first top dressing Apply it now and keep the second one on schedule. Late nitrogen is a problem only once the curd is visible.

Note down each year which sowing dates produced good heads and which produced buttons. Two seasons of that record narrows your own sowing window to about a week, and that is when cauliflower stops being difficult.