Starting seeds is easier than you may think:
Some seeds germinate best in cool soil, and others in warm; check the seed packet for temperature requirements. If the seeds demand warmth, place the flat near a heat vent or on an electric heat mat to warm the soil. Watch daily for emerging seedlings, and as soon as they appear, remove the plastic cover and move the flat to a sunny window or grow lights. At this point, many types of seedlings prefer cool growing temperatures around 65ºF.
Seedlings grown in a mix that includes compost probably won’t require fertilizer. In compost-free mixes, feed the seedlings lightly every 2 or 3 weeks after moving them to individual pots. Johnson recommends liquid kelp and fish emulsion, mixed at half the recommended rate.
Starting about 2 weeks before you plan to transplant the seedlings into the garden, move them to a sheltered spot outdoors for a few hours at a time. This process, called hardening off, allows the seedlings to adjust gradually to outdoor conditions such as wind and sun. “Slow down on water to let them toughen up,” Johnson says. “Be careful not to put them in direct sunlight right away.” Gradually increase their time outdoors and light exposure.
Indoor seed starting requires the gardener to develop new skills, but in the end, it’s worth it. As Johnson says, “Gardening is more rewarding when you start from seeds.”