If you live in southern Florida or Hawaii you can plant vegetables outdoors in January, but in most climate zones you must wait until after your final spring frost to set annual vegetables in the ground. You can get a head start on the season, however, when you use a cold frame, greenhouse or any warm, sunny indoor area where you can plant seeds and watch them grow until they're large enough to plant in your garden. Some vegetables do better than others when you choose this method, but with a few hints and tips, you can have success with many veggies.
Planting Vegetables in January
Select seeds of vegetables that prefer cooler weather, such as lettuce, spinach, edible-podded peas, cabbage, Swiss chard and broccoli.
Fill nursery flats or pots with standard potting soil and then water thoroughly, making sure water drains from the drainage holes. Wait until your pots stop dripping, then make rows for your seeds that are the correct depth for the type of seed you are planting. Rely on seed packet instructions for details.
Scatter small seeds throughout the soil surface, then cover them with a small amount of potting soil. Drop larger seeds into the rows you made and cover them with potting soil.
Place your pots or flats on a sheet of plastic if you will be using your house to grow your vegetables. If you are using a greenhouse or cold frame, make sure the temperature remains above freezing at night. Also make sure your pots receive as much sunlight as possible, or hang fluorescent shop lights several inches above the soil surface.
Keep the soil in your pots or flats moist at all times until you see sprouts emerging from the soil. After germination occurs, water your pots or flats every few days, or when the soil surface becomes slightly dry.
Fertilize your young vegetables with a balanced fertilizer about one month after they germinate. After about two months, many of your plants will be ready to set in the garden. Be sure to wait until after your final frost to transplant frost-tender summer vegetables such as tomatoes.