Start seeds indoors under grow lights for the best results. Seeds started and then placed in a window, even an extra-sunny south-facing window, often produce weak, leggy seedlings, according to the Cornell Cooperative Extension. Gardeners successful at seed starting choose to supplement with grow lights when growing their seedlings, if direct light, such as that found in a greenhouse, is not available.
Saturate the seed-starting mix bag with water. Open the bag and spray the interior mix. Place the saturated bag in a bucket to sit overnight. By morning, the mix will feel moist.
Pour the seed-starting mix into starter pots, filling until three-quarters full.
Place two or three seeds into each starter pot. Push the seeds 1/4-inch deep into the middle of the seed-starting mix. Sweep a light layer of mix back over the seeds.
Label each container to identify the plant variety planted in the container. Write the variety name on a piece of masking tape with a marker. Place the masking tape on the outside of the container.
Place the starter pots on a table, 6 to 9 inches away from a grow light hanging above the table. Keep the grow light turned on for 14 to 16 hours each day to give the growing seedlings adequate light exposure.
Water the seeds every day with a gentle stream of water from a watering can until the soil appears moist.
Cut weak seedlings from the plant when leaves develop. Cut weak seedlings at soil level with a pair of scissors. Leave only the strongest seedling on each plant.
Set starter pots outside daily, before planting, to harden off the seedlings. Start the hardening process two weeks before the expected planting date. Place the seedling containers in a shady location during the day, and bring them indoors at night. Each day, move the containers to a sunny location for an hour. Increase by an extra hour each day until the end of the two weeks.