Broccoli - Harvest when flower heads are firm and fully developed but before individual flowers start opening. Cut 6 to 7 inches below the flower head. Exclude sunlight when curds are 2 to 3 inches across by loosely tying the outer cauliflower leaves together with a rubber band above the curd. Curds exposed to sunlight rapidly become discolored, rough in appearance and coarse in texture. Collard Greens - Break off older lower leaves when they are 8 to 12 inches long.
New leaves grow for a continuous harvest.
Leaf lettuce - Cut older, outer leaves when they are 4 to 6 inches long. Young leaves will continue to grow and can be harvested over a long period of time. Larger leaves tend to become bitter and tough. Parsley - Harvest throughout the season as leaves reach 3 to 5 inches in length. Radish - Because radishes mature quickly, at least two crops can be grown per season.