Cool season plants grow best with a relatively cool air temperature (50 to 60 °F). These plants are the first ones to be planted in the garden year and then again in the fall. They grow well during the short and cool days of spring and fall. They can be planted several weeks up to a couple of months before the last frost date (around May 10th). Plant cool season crops as soon as the soil is workable in the spring. If planted to late in spring, the heat of summer will reduce their quality. They may become bitter, have lower yields or bolt (form flowers and go to seed). Light frost will not injure them.
Many cool season crops can be sown in early spring and again in fall. For fall planting, they must be planted early enough to reach maturity before winter weather, although there are a few winter hardy vegetables. Some of the best quality vegetables are produced during fall’s warm days and cool nights. Plants grown in the fall have a higher sugar content and better flavor.
Examples of cool season vegetables include asparagus, beets, broccoli, Brussels sprouts, chives, cabbage, carrots, cauliflower, Swiss chard, kale, leek, lettuce, onion, parsnips, peas, radishes, spinach, and turnips.
Warm season vegetables should be planted after the threat of frost of has passed. These plants require warm soils and air temperature for growth and fruiting. They grow best with long warm days and mild nights.
The growing season in our area is too short to allow for some warm season crops to be directly seeded in the garden. For example, if you plant a tomato seed, it will take 60-80 days to reach maturity depending on the variety. To be able to get tomatoes earlier in the season they are started indoors and then transplanted to the garden once the danger of frost has passed.
Examples of warm season vegetables include beans, corn, cucumbers, eggplant, melons, peppers, zucchini and summer squash, pumpkin and winter squash, sweet potato and watermelon.
Submitted by Amanda Sears, Agent for Horticulture, Madison Co. Cooperative Extension Service