Light and Temperature
Provide bright light: Give seedlings 12 to 16 hours of light daily using grow lights placed 1 to 2 inches above the plants, or put them in a very bright, sunny spot.
Maintain mild warmth: Keep ambient temperatures around 65°F to 75°F during the day.
Improve airflow: Run a small, gentle fan nearby to strengthen stems and prevent mold
Watering and Feeding
Water carefully: Keep the potting mix evenly moist like a wrung-out sponge, but never soggy.
Use bottom watering: Set seedling pots in a shallow tray of water for a few minutes so roots absorb moisture from below without soaking the stems.
Feed lightly: Apply a half-strength, diluted liquid fertilizer once true leaves appear and nutrients run low.
Moving Outdoors
Harden off slowly: Acclimatize seedlings to outdoor wind and sun over 7 to 10 days by placing them outside in a sheltered, shady spot for a few hours at first.
Transplant safely: Plant them into your garden beds or larger containers once they have multiple sets of strong leaves and local weather conditions are frost-free.