Broccoli is a cool season vegetable that is in the cabbage or cole family. It grows best when the daytime temperatures are between 65F and 80F. Broccoli needs a fertile, well drained, moist soil with lots of added organic matter. The soil pH should be between 6.0 and 7.0 for best growth. Have your garden soil tested and adjust the pH according to the recommendations.
Transplants are best for spring plantings because they get the plants established more quickly and they can produce the crop with minimal interference from the early summer heat. The transplants should be planted 16-18" apart with 24" inches between rows. A liquid starter fertilizer applied at the time of transplanting helps get the plants off to a good start. Adding an organic mulch will help to keep the soil cool and moist and keep the weeds to a minimum.
Harvest the broccoli when the center flower head is dark green and fully formed but before any yellow petals begin to show. Any sign of yellow in the buds indicates the head is overripe. Cut the head free from the stalk 5-6" down from the head. Many varieties will continue to produce smaller side shoots as long as there are a few leaves on the plant which can extend your harvest for several weeks.