When To Sow: January-March (early); March-May (main crop); May-July (fall/winter crop)
Harvest: June-September (early crop); August – October (main crop); December – March (fall/winter crop)
Germination: 6-14 days Full Sun
Cauliflower grows best in rich, well-drained, moisture-retentive soil with a pH between 6.5 and 8.0. (If your soil has a history of club root, make sure your pH is closer to 8.0.) Choose a sheltered location, as cauliflower does not like extremes of temperature, either hot or cold. It also doesn’t tolerate dry conditions. Add aged compost to the bed before planting, but stay away from adding too much nitrogen (this can cause the heads to get “ricey,” where the curds separate out into small, rice-like grains).
Starting Indoors: Start indoors no more than 4-6 weeks before the last frost. Keep the soil warm (about 75F) until germination. Sow 1-2 seeds per module and cover with 1/8” fine soil. Keep the soil moist, but not wet. Once germinated, keep the seedlings around 60F and provide direct sun so they don't get leggy. Once plants are 4-6 weeks old (i.e. after your last frost), harden off gradually and transplant out with a spacing of 15-24”, in rows 2-3’ apart.
Direct Seed: Sow 15-24” apart, in rows 2-3’ apart once all threat of frost as passed and the soil temperature has reached 65°F and 75°F. Do not wait too long, however, as cauliflower truly loves cooler temperatures.
For a fall crop, direct seed 8-12 weeks before the first expected frost in fall.
Maintenance
One of the most important issues with cauliflower is that it needs continual, evenly moist soil for uninterrupted growth and head formation. Do not let the ground dry out, but also do not over water.
As cauliflower has a shallow root system, avoid even the shallowest of cultivation. Instead, mulch to protect the roots, reduce weeds and conserve moisture.
Here in the U.K., pigeons love our brassicas. If you find them stealing your seedlings, place netting over your beds.
If grown in cool temperatures, Snowball cauliflower does not need to be blanched, as the leaves will stay wrapped around the curds.
Cauliflower can be sensitive to boron deficiencies.
Harvesting
Snowball cauliflower is ready to harvest when the heads reach a size of 6-8” and the curds are still tight. (Waiting too long can cause the curd to become grainy in texture.) Cut the whole head from the stem, leaving a few leaves around the curds to protect them and prolong storage quality. The leaves are also tasty when cooked like cabbage or collards.
Transfer heads to a cool location immediately after harvest to retain quality.
Companion Planting
Cabbage grows well with beets, celery, herbs, onions, and potatoes. Avoid pole beans, strawberries, or tomatoes.