Step 1: Broccoli can germinate in soil with temperatures as low as 40ºF.
Step 2: Broccoli requires full sun and moist, fertile soil that's slightly acidic. Work in 2 to 4 inches of rich compost or a thin layer of manure before planting.
Step 3: For spring plantings, seed or set transplants 2 to 3 weeks before last spring frost date. If you transplant, assume 10 less days for growth or the "days to maturity" on the seed packet.
Step 4: For fall plantings, seed 85 to 100 days before your average first fall frost. If you live in a warm climate, a fall planting is best, as broccoli thrives in cool weather. Plant seeds in mid- to late-summer in most places.
Step 5: Plant seeds 1/2 inch deep, or set transplants slightly deeper than they were grown originally.
Step 6: Within a row, space your plants 12 to 24 inches apart with 36 inches between each row.
Step 7: Space plants 12 to 24 inches apart, depending on the side heads you want to harvest.
Step 8: If you overseed, you will need to thin seedlings to 12 inches apart to give room for the broccoli to grow.
Step 9: Provide consistent soil moisture with regular watering, especially in drought conditions. Some varieties of broccoli are heat tolerant, but all need moisture.
Step 10: In terms of timing: Harvest broccoli when the buds of the head are firm and tight before the heads flower. If you do see yellow petals, harvest immediately.