Biennial vegetables normally require two growing seasons from seed to flowering. Biennial vegetables include beets, Brussels sprouts, cabbage, carrots, cauliflower, celery, chard, collard, endive, kale, kohlrabi, leek, onion, parsley, parsnip, rutabaga, salsify, and turnip. When young biennial plants are subjected to cold weather early during their growth, they may produce seed the first season.