1.Plan to sow seeds in your greenhouse at any time of the year. When you want to transplant your seedlings into the garden in spring, sow seeds in the greenhouse about six to eight weeks before your area's last frost date.
2.Soak large seeds, such as beans or tree seeds, in a bowl of warm water overnight before planting them. 3.Fill seed-starting trays with moist potting soil. Sow one large seed per tray cell. If the seeds are very small, pinch a few between your thumb and forefinger. Spread them across the surface of the soil and tamp them down with your fingers. 4. Sprinkle a very thin layer of sphagnum moss or vermiculite over the surface of the soil, if desired. Do not do this, however, when your seeds need light to germinate. Examples include petunia and lettuce seeds, as well as many small herb seeds. 5.Mist the surface of the soil with a spray bottle. When seeds require high humidity or constant moisture, put the tray in a clear plastic bag until germination occurs. |
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6.Put seed trays on a heating mat to encourage faster germination. Ideally, use a mat with a thermostat so the soil does not get too hot. Many seeds prefer a soil temperature between 70 and 85 degrees Fahrenheit.
7.Keep the greenhouse temperature around 50 degrees Fahrenheit at night and around 70 degrees Fahrenheit in the daytime. When a heater is necessary to raise the temperature, provide ventilation by opening a window or door. 8.Put seed trays under hanging fluorescent lights when your greenhouse receives less than 16 hours of sun per day. Keep the lights about 6 inches above the trays. 9.Provide water as necessary to keep the soil moist before germination and during the seedling stage. 10Thin seedlings to one healthy plant per tray cell. When seedlings have at least two true leaves, transplant them into larger individual containers. 11.Spread out the containers in the greenhouse. Avoid pushing containers close together. Doing so prevents adequate air flow. Keep a fan blowing gently at all times to simulate the wind that normally helps plants grow thick, strong stems. 12.Give seedlings a half-strength application of all-purpose, soluble fertilizer when the first true leaves appear. 13.Begin hardening off plants two weeks before transplanting into the garden. Start hardening off in early spring or after your Sunset's Climate Zone's last frost date. Move the plants outside to a shady spot for several hours each day. Gradually increase the hours per day the plant spends outside over the two-week period. 14. Transplant the plants into their permanent locations in the garden when hardening off is complete. |