Starting garden seeds indoors offers an early start on the growing season while the weather is unsuitable for planting. While a sunny window may provide enough light for seedlings to grow, chances are that it won't provide enough even light and that they will be subject to drafts and temperature fluctuations. Grow lights give more control over these conditions and ensure healthier seedling growth.
Fill seed-starting pots or flats with a quality potting mixture. Moisten the soil evenly throughout before sowing the seeds.
Sow the seeds to a depth twice that of their circumference or sow extremely small seeds directly onto the soil surface and cover with 1/8-inch of soil. Sow two seeds per pot or space the seeds 2 inches apart in flats.
Cover the seeds with plastic wrap and place in room to germinate at 65 to 70 degrees F. Remove the plastic when the seedlings emerge from the soil, approximately seven to 14 days after planting for most varieties.
Place cool-white and warm-white fluorescent bulbs in a dual-bulb fixture. Install the fixture in a room that is 70 to 75 F.
Stack newspapers, boxes or old phone books under the light fixture, then place the seedling pots on top. Stack them high enough so that the seedling tops are 3 inches beneath the bulbs. Remove boxes or papers from the stack to maintain the distance as the seedlings grow.
Keep the soil moist at all times. Water as needed to maintain even moisture, but do not allow it to become soggy.
Leave the lights on for 12 to 16 hours a day, turning them off at night. Plants require on average of twice as much artificial light as they do natural light.