Growing your vegetables in a cold frame is an excellent way to ensure that you have edible crops for harvest over the cold winter months. Choose cold-hardy plants such as lettuces, round finger carrots, or dark leafy greens for growing in the winter. Hot-weather-loving plants such as tomatoes and peppers can be started in a cold frame during the last stage of winter. They can then be transplanted to your garden once all danger of frost has passed.
Install a cold frame. Commercial kits are available, or you can build one yourself out of 2-by-4s and an old window sash. A cold frame is simply a glass-topped, open-bottomed frame that sits on soil and guards plants against cold. The glass helps the box act as a miniature greenhouse.
Select cold-hardy vegetable seeds. Lettuces, spinach, kale, chard, green onions and round finger carrots are all good choices for vegetables to grow during fall and winter.
Sow seeds directly in the cold frame according to package instructions. Different varieties require different planting depths. Lettuces, as a rule, need very little dirt to cover them. Some lettuces even do best when simply broadcast on top of the soil rather than buried.
Water and fertilize sparingly. Winter watering needs are less than summer ones, but will vary wildly according to the weather. Be observant. Follow your fertilizer's instructions for application.
Start seeds for a warm weather garden in your cold frame instead of starting them indoors. Sow tomatoes, peppers, cucumbers, and other hot-weather-loving plants as package directions instruct in early spring, about six to eight weeks prior to the final frost date. Water regularly and fertilize according to package instructions.
Transplant hot-weather seedlings into your garden after they have grown 6 to 8 inches tall, and all danger of frost has passed.
Use the cold frame for succession gardening to keep a year-round harvest available. Plan your garden ahead so you always have different seasonally-appropriate plants cycling through different stages of growth for a continual harvest.