According to Colorado State University, plants can be divided into two groups: cold-weather vegetables and warm-weather vegetables. Cold-weather vegetables include root crops such as carrots and onions as well as low growing green vegetables such as lettuce, broccoli and cabbage. Cold tolerant vegetables are grown in the summer in cooler climates. In warmer climates, they can be planted in early spring and late fall to extend the gardening season by up to a month.
Wait until the proper time to plant cold-tolerant vegetables for your heartiness zone. This may be up to two weeks before the last annual frost date in spring. In warmer climates, a second cold-tolerant crop may be started in the early fall.
Sow cold-tolerant vegetable seeds directly into the ground. Cold weather vegetables are more hearty when grown this way than when transplanted.
Stop watering plants as winter sets in to prevent them from freezing.
Erect protective screens, such as row covers, to protect your plants from the elements. In colder zones, such as zone 4 or lower, you may wish to construct a hoop-house greenhouse around your garden for additional cover.
Wait at least two hours after the temperatures have heated to above freezing to harvest them.
Harvest plants at ground level by cutting the stem in half.