Broccoli is a cool-weather vegetable, which makes it ideal for early spring or fall planting. It prefers being grown where daytime temperatures remain around 60 degrees Fahrenheit. As a cole crop, broccoli is a member of the same family as cabbage and Brussels sprouts. When sowing broccoli seeds it's recommended you start them early indoors about 8 weeks before the last anticipated frost date in your growing region.
Planting Broccoli Seeds
Pack a good-quality seed compost into plastic planting packs until they are filled to nearly 1/2 inch from the top of the rim.
Place two to three broccoli seeds into each of the cells in the planting packs. If handling the seeds proves difficult, you can use a pair of tweezers or forceps to pick up the individual seeds.
Cover each of the broccoli seeds with approximately 1/4 inch of seed compost.
Place the planting packs in a cool location that is not in direct sunlight. The temperature should remain at about 60 to 65 degrees Fahrenheit. Check on the planting packs at least once a day to make sure the seeds are kept moist. Mist them with a fine spray of water as needed. Broccoli seeds should begin sprouting between 10 and 14 days after planting.
Transplant the seedlings approximately five weeks after germination.
Locate a suitable site, in full sun, for planting the broccoli. Broccoli needs a minimum of between five and six hours of direct sunshine daily for optimum growth.
Prepare the garden site about two to three weeks before translating the broccoli. To do this, break up the soil to a depth of about 10 to 12 inches to work in a 3- to 4-inch layer of aged steer manure or plant-based compost.
Incorporate into the soil between 1 and 1 1/2 pounds of 8-16-16 fertilizer for every 50 square feet of planting areal. Mix the fertilizer thoroughly into the soil using a fork or a spade.
Create 2- to 3-foot-wide rows in the planting area that are about 24 inches apart.
Dig holes down each row that are the same size as a cell in the planting pack. The distance apart for each hole should be approximately 24 inches.
Pop out a broccoli seedling from a cell using your thumb. Place the seedling into the hole. Hold the seedling level in the hole while you slide soil in and around the seedling. Firm the soil down around the seedling.
Mix together 1 to 2 tablespoons of a 20-20-20 or 10-10-10 starter fertilizer made especially for vegetable transplants with 1 gallon of water. Water each of the broccoli seedlings with approximately one to two cups of the solution.