Starting seeds indoors
Starting seeds indoors is a simple way to enjoy many plant varieties not commonly found in garden centers. The equipment you need to start seeds indoors ranges from the simple to the complex. For optimal results, begin with a seed-starting tray filled with a sterile potting mix and a capillary or wicking, mat underneath to water the seedlings from below.
The best temperature for starting most seeds is 72 degrees Fahrenheit during the day with a cooler nighttime temperature that doesn't drop below 65 degrees Fahrenheit. Take care not to expose seeds to cold drafts, and follow seed-package directions for depth of planting. Plant seeds, water them, and then cover them with plastic wrap until the seeds germinate. After germination, remove the plastic wrap.
Suspend fluorescent lights three inches above the tray to provide light -even if you have some natural light. As the seedlings grow, raise the light fixture to maintain the three-inch separation. When no supplemental natural light is available, add an incandescent bulb to produce better plant growth. Position the incandescent light bulbs so that the heat they produce does not burn the seedlings. For best growth, keep the lights on 12 to 16 hours daily.
After seedlings emerge and develop four leaves, fertilize with a quarter-to half-strength water-soluble fertilizer to stimulate good, even growth. Transplant seedlings in their own pots to provide room to grow. About two weeks before setting plants in the garden, be sure to harden them off by moving them outdoors on warm days and back inside at night.
For "Buying & hardening transplants" refer to message number 1802.
For more information, see the following Colorado State Extension fact sheet(s).
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Updated Friday, April 19, 2013