Planting dates vary widely in Utah depending on local climate conditions. Planting may begin in February in southern Utah (Washington County) and may be as late as early June in cooler mountain areas of northern Utah. Planting is recommended after the danger of hard frost has passed. Access local freeze dates through the Utah Climate Center.

Brassica seeds germinate well in cool soils (below 60 °F) and is most rapid around 75 °F. Plants grow best when the mean daily temperatures are 60 °F to 70 °F and brassicas easily withstand night temperatures below 40 °F. Transplants can withstand temperatures below freezing for short periods, provided they are well conditioned. Large broccoli or cauliflower transplants (six to eight leaves) may prematurely head out (button) if exposed to cold temperatures, while cabbage may not form a head (blind) if excessively chilled. Temperatures above 85 °F significantly slow plant growth, alter head shape (more pointed) in cabbage, and decrease head/curd quality in broccoli and cauliflower. Cauliflower curds and broccoli floral buds grow unevenly (rough head appearance), discolor (yellow), and often have small leaves (bracts) growing up through the heads when exposed to high growing temperatures.

Plant and row spacings vary with cultivar grown, plant growth habit, available equipment, irrigation approach, and market requirements. The following spacings in Table 4.3 are common and only provided as recommendations.

Brassica Row Spacing

Crop	Between Rows (ft.)	Within Rows (in.)	Plants/acre
Brussel sprouts	2.5-3.5	18-30	5,000-12,000
Cabbage, Broccoli, Cauliflower	1.5-2.5	8-24	8,700-40,000
Kohlrabi, Mustards, Pak choi, etc.	1-2	6-15	17,500-87,000

For direct-seeded brassicas, precision plant at 0.5-1.5 pounds seed per acre and place seed ⅓ to ½ inches deep (depending on soil moisture, time of year, and irrigation availability). Thin direct-seeded plants to final spacing when they have three to five leaves.