Gardeners grow seedlings in a controlled indoor environment to assure they have the strongest and largest plants possible to plant in their garden. Growing seedlings indoors allows you to extend your growing season past your local seasonal constraints resulting in much earlier harvests.
Growing seedlings from seed:
Location: If you are growing seedlings indoors, find a warm place with direct sunlight for at least 8 hours per day. If you do not have adequate light, you will need to purchase indoor grow lights. If your plants do not have enough light, they will grow ‘leggy’. Leggy plants grow tall and weak and typically are not strong enough to survive when they are planted outdoors.
Timing: Check the seed packet for specific directions on when to plant indoors. A common recommendation would be, “Plant indoors 4-6 weeks prior to average last frost”
To ensure you grow strong and large seedlings, plant more seeds than you intend to grow and once all the seeds have sprouted, pull out the weakest plants and leave one seedling that you think will grow into the strongest and largest plant.
Caring for seedlings for a week before planting:
If you purchased or were given seedlings that will soon be planted in your Learning Garden, you will need to keep them in good condition until your classroom is ready to plant. Your seedlings will do well indoors or outdoors with proper sunlight and watering. Seedlings will do best in a shady spot with good ventilation. Consider following the directions to harden off your seedlings while you hold yours for a few days.
Hardening off seedlings:
When seedlings are grown indoors under fairly consistent lighting and temperatures with no wind, they will need to be introduced to the outdoors slowly. Ideally, seedlings should be able to adapt to outdoor conditions in 7-10 days.
Step 1 (2-4 days): Get your seedlings accustomed to daytime temperatures and wind. Find a shady location with minimal exposure to wind and keep your seedlings there for 1-3 hours during the warmest part of the day. Make sure you do not forget to bring them back indoors.
Step 2 (2-4 days): Strengthen seedlings and expand their endurance to a wider range of temperatures and light. Continue to bring your seedlings outdoors to a shady spot during the day, and if temperatures are not extreme then keep them outdoors for a full day. Make sure you do not forget to bring them back indoors.
Step 3 (2-4 days): Work towards exposing your seedlings to outdoor conditions for 24 hours before planting in the ground. Use good judgement here and do not leave seedlings outside during a storm, near freezing temperatures, or high winds.