By Tina Marie Wilcox, HSA Ozark Unit and 2017 Nancy Putnam Howard Award for Excellence in Horticulture
Get a jump on the growing season, save money and expand your selection of summer annuals by starting seeds early inside. First, research online and in catalogs for the time, temperature and light that your seeds need for germination. Find out if the plants are best planted directly into the garden and the days to harvest.
Reputable seed companies test their products for viability. If your seeds have not been tested, you can do this yourself to save time, potting medium and growing space.
Use thin, plastic sandwich bags that fold down (zip-lock varieties are not as good), white paper towels and a permanent marker. Label each bag with the seed variety and the date. Count out a specific number of seeds to test for viability. I usually test ten seeds.
Fold the towel in half three times to form a rectangle. Moisten the towel. Unfold it once and sprinkle the seed inside. Refold and slip the towel into the labeled bag. Loosely fold the bag to retard evaporation while allowing air exchange.
If the seeds require light to germinate, sprinkle them on the outside surface of the folded towel and slip it into the bag. Do not put bags in direct sunlight, as this will overheat the seeds. To regulate periods of light and darkness, place the bag, seed-side-up, under 40-watt florescent lights at a distance of 8-inches below the lights. Plug the lights into a timer to provide cycles of day and night.
Most importantly, place them in a warm place where you will remember to check for germination on a daily basis. As soon as the seeds split and taproots immerge, you know the seeds are viable.
A word of caution, do not plant too early. Housing summer annuals undercover for an extended time does not necessarily yield early production. Here in Zone 7a, our last average frost date is mid- April. We usually wait until after April 20th to set tender seedlings in the garden. Check out http://planthardiness.ars.usda.gov/PHZMWeb/ to find your zone.
Assemble pasteurized growing medium, sterile containers and labels. In the Heritage Herb Garden greenhouse, we use deep, 3-inch plastic pots. These fit tightly into flats (trays). We use two flats under the pots for added strength and security during transport.
Fill the pots evenly with pre-moistened medium. Seeds that require light to germinate should be sprinkled on the surface of the medium. If they require darkness, the rule is to plant two-and-one-half times the thickness of the seed deep. Gently press the medium down into the pot, sow one to three seeds into each pot. Then cover with the proper amount of growing medium. Sprinkle water on the surface to settle the medium and seed. Finally, cover the pot(s) with a plastic dome or slip them into a clear plastic bag. You can also stretch plastic wrap over the top. Covering the medium keeps it evenly moist and is a temporary barrier against fungus gnats. Remove the covering as soon as the majority of seeds have germinated.
The growing medium temperature will be equal to the ambient temperature. Some growers use heat mats to maintain a constant temperature. This does speed germination time for summer annuals.
Plants kept in captivity will require strong light, fertilizer, and room for their roots as they grow. Leggy growth is a sign that the plants need more light. If growth slows and the bottom leaves get yellow, the plants are root-bound. Provide adequate light and transplant as needed or the plants will be irreparably damaged. Before the plants can be planted out to the garden they must be hardened-off. Move them to a protected porch or cold frame for several days before subjecting them to the elements.
May your seeds germinate and thrive.