Types of Plants–Very Tender, Tender, Semi-Hardy and Hardy
Plants can be divided into several types depending on how well they tolerate cold, freezing temperatures, and frost.
Hardy plants require less light (3-6 hours of direct sun), can tolerate hard frost, and grow best in cool weather. Many will die, bolt, or go to seed when temperatures rise. These should be planted early in the spring, as soon as the soil can be worked (soil temperature 40°F/5°C), or late in the summer to be harvested in the fall. In areas with short periods of frost, hardy vegetables can be grown all winter.
Some examples of hardy vegetables: Asparagus, Broccoli, Cabbage, Kale, Kohlrabi, Leeks, Onions, Peas, Radish, Rhubarb, Rutabaga, Spinach, Turnip
Semi-hardy plants require more sun (6 hours), tolerate light frost, and grow best in cool weather. Some of them can tolerate heat, but many will bolt or go to seed when temperatures rise. These should be planted in the spring, about 3-5 weeks before the frost date. They can also be planted late in the summer for a fall harvest, or during the winter in temperate regions without any frost.
Some examples of semi-hardy vegetables: Beets, Carrots, Cauliflower, ENdive, Lettuce, Mustard, Parsley, Parsnip, Potatoes, Swiss Chard
Tender plants need more sun (8 hours), do not tolerate frost, and grow best in warm (not hot) weather. Any frost will kill them, so they should be planted on or after the frost date, which usually occurs in late spring or early summer.
Some examples of tender vegetables: Celery, Corn, Cucumber, Dry Beans, Snap Beans, Summer Squash, Zucchini
Very tender vegetables require a lot of sunlight (8-12 hours), will be stunted by cold temperatures, and grow best in very warm weather. They should be planted after all danger of frost has passed, about 3 weeks after the frost date.
These vegetables have long growing seasons (they take a long time to go from seed to harvest), so you want to wait until the weather is warm enough for them, but you can’t wait too long or you will not have a chance to harvest before hot or cold temperatures set in. For this reason you should use transplants, not seeds.
Some examples of very tender vegetables: Cantaloupe, Eggplant, Lima Beans, Melons, Okra, Peppers, Pumpkins, Tomatoes, Winter Squash
Here is a chart that lists many vegetables and their category.
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