By National Gardening Association Editors, June 23, 2008
- Two broccoli crops a year are possible in many areas.
- Start spring transplants indoors 5 to 7 weeks before the last spring frost date, or buy nursery transplants 3 weeks before the last spring frost date.
- Plan to seed fall crops 85 to 100 days before the average first fall frost date.
- Where the weather is warm, select a variety that is bolt resistant.
- Add 3 to 4 pounds of 5-10-10 or its equivalent per 100 square feet before planting.
- Set out transplants 3 to 4 weeks before the last spring frost.
- Set the transplants 6 to 18 inches apart, with 20 to 36 inches between rows, depending on the fertility of the soil.
- Protect transplants from hard frosts with newspapers, plastic cones, paper bags, or baskets. Provide a windbreak to reduce transplant shock and moisture loss.
- For fall crops, direct seed the broccoli in the garden. Sow the seeds 1/4 inch deep, 2 to 4 seeds per foot of row, leaving at least 20 to 36 inches between rows, depending on soil fertility.
- Thin direct-seeded seedlings when they are 4 inches tall. In rich soil, thin seedlings to stand 6 to 12 inches apart. Where soil is of average fertility, thin seedlings 12 to 18 inches apart.
- Side-dress each plant 3 weeks after setting out transplants or 5 weeks after sowing from seed with 1 tablespoon of fertilizer high in nitrogen.
- See our article Summer's Bad Guys by Charlie Nardozzi for controls of common broccoli pests such as flea beetles, cabbageworms, and cabbage loopers.
- Harvest for peak quality when the buds of the head are firm and tight. If buds start to separate and the yellow petals inside start to show, harvest immediately.