A fresh, home-grown crown of cauliflower is a thing of beauty – crisp, nutritious, and intensely flavourful. Among the Brassicas, it is mild in flavour and surprisingly versatile in the kitchen. Continue reading for some tips on how to grow cauliflower from seed.
Brassica oleracea var. botrytis
Season & Zone
Season: Cool season
Zone: Overwintering types are only hardy down to -12 to -19°C (16 to -5°F).
Start indoors four weeks before the last frost to late spring. Transplant in 5-6 weeks. Direct seed when temperatures are reliably above 10°C (50°F). Overwintering types are started in July where winters are mild, and transplanted by August 15th. Optimal soil temperature: 10-30°C (50-85°F). Seeds should germinate in 7-10 days.
Sow 3-4 seeds 5mm (¼”) deep in each spot you want a plant to grow. Thin to the strongest plant. Space transplants 45-60cm (18-24″) apart in rows 60-90cm (24-36″) apart.
Days to Maturity
From transplant date.
Ideal pH: 6.0-6.8. Humus-rich soil amended with composted manure is best. Mix ½ cup of complete organic fertilizer into the soil beneath each transplant. From seedling to harvest, cauliflower must grow steadily to make a large plant and curd. If growth slows, scratch additional fertilizer into the surface of the soil around each plant. Maintain even soil moisture with regular watering. Shade the developing curds from sun by tying up leaves or using newspaper. This is known as “blanching,” and will keep them white. Add 20-25 days to the maturity dates if direct sowing.
Once curd forms, check every day and cut when the florets are just beginning to separate. At this point the flavour is at peak quality and the size is maximum.
In optimal conditions, at least 80% of seeds should germinate. Usual seed life: 3 years. Per 100′ row: 200 seeds, per acre: 44M seeds.
Diseases & Pests
Slugs and snails – Slugs are attracted to beer, so place a little beer in a cup dug into the ground. Sprinkle broken eggshells around plants to deter slugs and snails.
Flea beetles – Use row covers to help protect plants from early damage. Put in place at planting and remove before temperatures get too hot in midsummer. Control weeds.
Cabbage root maggot – White maggots (larvae) attack all plants of the cabbage family. Larvae tunnel in and feed on roots of plants. Damage causes wilting early on, death of plants a little later on.
Cabbage aphids – A hard stream of water can be used to remove aphids from plants. Wash off with water occasionally as needed early in the day. Check for evidence of natural enemies such as gray-brown or bloated parasitized aphids and the presence of alligator-like larvae of lady beetles and lacewings.
Cabbageworms – Hand-pick and destroy. Row covers may be useful on small plantings to help protect plants from early damage. Put in place at planting and remove before temperatures get too hot in midsummer.
To help reduce disease, do not plant cauliflower or other Brassicas in the same location more than once every three or four years.
All Brassicas benefit from chamomile, dill, mint, rosemary, and sage. Avoid planting near eggplants, peppers, potatoes, or tomatoes.
More on Companion Planting.