Broccoli is a cool-season crop that can be planted in late winter for spring harvest and in late summer for a fall harvest. While frozen ground in winter usually requires you to raise spring broccoli from transplants, fall crops can be grown from seeds sewn directly in your garden. Broccoli contains vitamins A, C, D and beta carotene, according to the University of Illinois, which rates this vegetable as the most popular cruciferous vegetable in the United States.
Determine the average first frost date for your area. This information is available from your local county extension office or online. Consult the seed packet to find the days to harvest for the variety of broccoli you have chosen. Add ten to this number. Count backwards this many days from the first frost date to determine the date you should plant your broccoli seeds.
Prepare the soil by clearing it of all weeds and large stones. If this is a new bed, dig the soil to a depth of 10 inches or more with a shovel, breaking up the clods of dirt, then raking it smooth. Work in composted manure or compost.
Plant seeds ½ inch deep. Plant seeds 12 inches apart in rows that are also 1 foot apart. Make a dimple in the soil with your finger or a stick, drop the seed in and rake soil lightly over the seed.
Water the bed where the broccoli seeds are planted. Use a hose nozzle with a sprinkler nozzle to avoid disturbing the seeds.
Water daily to keep the soil moist until the seeds germinate. Water until soil is moist to a depth of 1 inch. Continue to water as needed to keep the soil moist to a depth of one inch as the seedlings emerge and throughout the life of the plant. Broccoli especially needs regular water as the heads form.
Work in a high-nitrogen fertilizer around the plants when you see the beginnings of a broccoli head forming at the center of the plant.
Harvest the broccoli when the head is full and round, but before the buds begin to open and flower. Cut off the stem with a sharp knife where the stem meets the main plant. Leave the broccoli plant in place to produce side shoots, which can also be harvested and eaten.