Whether you are starting a vegetable garden or want to grow ornamentals for your decorative beds, getting your plants from seeds instead of purchasing seedlings is less expensive. Seeds also give you a greater choice in plant varieties, allowing you to customize your beds to your desires. Seed starting requires patience and some planning to ensure the plants are ready for the garden at the right time. Most seeds are started in early spring and transplanted outdoors once the last spring freeze passes.
Fill seedling flats with a quality soil-less potting mix. Soil-less mixes are sterile and light, providing the optimum seed-starting medium.
Moisten the potting mix so that it is evenly moist throughout but not soggy. Either water it from the top and allow the excess moisture to drain out the bottom, or fill the bottom tray with water and allow the mix to absorb the water until it is moist on top.
Plant medium and large seeds to a depth twice that of their width, spacing them 2 inches apart in all directions. Make furrows in the mix with a pencil, spacing each furrow 2 inches apart. Sprinkle the small seeds into the furrow then gently press them into the soil with the back of a spoon.
Cover the tray with a layer of plastic wrap to preserve moisture during the germination process. Place the tray in a warm, 70 to 75 F room. Alternately, place the tray on top a seedling heat mat set to 75 F.
Remove the plastic wrap once seedlings emerge, approximately seven to 14 days for most varieties. Adjust the heat mat down to 70 F, if applicable. Place the tray under grow lights positioned 3 inches above the top of the seedlings.
Keep the soil moist at all times, watering as necessary to prevent it from drying out. Leave the grow lights on or twelve hours a day to provide enough light so the watering doesn't lead to fungal diseases.
Transplant the seedlings to individual pots once they produce their second set of leaves. Fill pots with the same soil mix, dampen it, then gently lift the seedlings from the tray by their leaves and plant them to the same depth in the pots.