SOWING: Broccoli prefers a well-drained, fertile soil high in organic matter, and a pH of 6.0–7.5 with a consistent supply of moisture throughout the growing season. Irrigate regularly for best results. Broccoli does not generally do well in hot weather. The best success is with spring and fall crops.
EARLY SPRING CROP: Use early and midseason broccoli varieties in spring. Sow 2 seeds per cell or 3–4 seeds/in. in row flats. Seedlings should be ready to transplant in 3–4 weeks. If possible keep soil temperature at 80°F until germination, then reduce air temperature to about 60°F. Ensure good air circulation and light. Transplant outdoors 10–18″ apart in rows 18–36″ apart. Broccoli prefers cooler growing temperatures, between 55–75°F but will produce good crops under warmer, summer conditions.
FALL CROP: Start seedlings indoors 3-4 weeks before transplanting. as above in May and transplant to the garden in June–July. To ensure mature heads, seed the crop early in areas where heavy freezes occur early in fall.
WINTER CROP: Successful broccoli crops can be grown where winters are rarely below 32°F. Transplants can be set out from September to February in these regions.
DIRECT SEEDING: Sow 3–4 seeds 12″ apart, ½” deep, rows 18–36″ apart, thinning to one plant in each group.
INSECT PESTS: Repel flea beetles and root maggots on young seedlings by covering with floating row covers from day of planting. Treat flea beetles with pyrethrin or azadirachtin if heavy pressure is observed. For cabbage worms and loopers, use Bacillus thuringiensis (Bt.).
HARVEST: Before flower buds open, cut center head. Harvest secondary side shoots regularly to encourage continued production.
AVG. PRECISION SEEDING RATE: 1,000 seeds/83′, 50,000 seeds/acre spaced 7″ apart in rows 18″ apart.