Tomato seedling, one day old
image by tomato seedling, Fern Fischer; seedling flat, mrmac04/morguefile.com
Some vegetables are direct-seeded into the ground. Others need to be started from seeds indoors and raised as seedlings until they are sturdy enough to be transplanted to their permanent garden spot. If you live in a cold, northern area, starting seeds indoors extends your growing season.
Wash your planting containers in hot, soapy water and rinse them completely. Clean pots will help thwart many plant diseases. You can use any household containers, such as egg cartons or yogurt cups. Garden centers sell plastic trays specifically made for starting seeds. These usually have a clear dome protective cover and proper drainage for seedlings and are reusable. Some are long and narrow for windowsills, and others are large flats with room for several dozen seedlings.
Punch drainage holes in the bottom of containers if they have none. Fill the containers with sterilized potting medium. Sterilized growing medium prevents soil-borne diseases and limits the risk of damping off, a fungus infection that kills young seedlings. Water the planting medium so it is moist before you plant seeds.
Commercially prepared planting pellets or cubes are another way to start seeds. These are preformed growing medium. Some are compacted and swell to seeding size when you add water.
Plant one seed in each compartment or pot at the depth indicated on the seed packet. Small seeds like tomatoes, peppers, eggplant, broccoli and cabbage are planted about 1/4 inch deep. The time to start most seeds indoors is 10 to 12 weeks before the last expected frost in your area.
Cover the containers with their domes or with plastic wrap to prevent moisture loss, and keep them in a warm place (about 70 degrees) away from drafts and temperature changes. Gentle bottom heat helps seeds germinate faster. Use a commercial plant heating mat, or place on top of the refrigerator. Light is not important at this stage, because no photosynthesis is taking place.
Check the containers daily. Water gently from the bottom if necessary, and use tepid water to avoid cold shock. As soon as seeds begin to sprout, move the containers so they receive bright light.
Continue to provide plenty of light and moisture. Soil should never be soggy. Set plant lights 12 to 15 inches above the tops of the plants, and adjust them as the plants grow. Turn plants that are in your windows so they get even sunlight on all sides and grow straight.
Move each plant into its own cell or pot when it has its first set of true leaves. Provide mild, balanced fertilizer such as diluted fish emulsion. Continue with light and water, and avoid drafts.
Begin exposing your young plants to the outdoors 7 to 10 days before outside planting time. Place them in a sheltered location for a few hours a day, increasing the time as the week progresses. This is called "hardening off" your plants. They will be acclimated to the outdoors and will not be as likely to suffer transplant shock when you set them out.