Now is the time to start seeds that need to undergo a moist, cold period before they sprout.

        These include the seeds of many perennials, such as monkshood (Aconitum spp.), penstemon, garden phlox, turtlehead (Chelone spp.), bleeding heart (Dicentra spp.), columbine (Aquilegia spp.) and globeflower (Trollius sp.).

        It's also time to start seeds of many fall-ripening trees and shrubs, such as species roses, viburnums, barberries and dogwoods.

        The method of starting seeds in the cold is called stratification. The process replicates the natural conditions seeds would undergo in their native habitats. This simple process will enable seeds to germinate when warm temperatures arrive in the spring.

SOURCES

• Gardening by Mail (Mariner Books; 1997) by Barbara J. Barton.     • The North American Rock Garden Society, P.O. Box 67, Millwood, NY 10546-0067; www.nargs.org

        To try stratification:

        • Use 4-inch plastic pots or flats. If the containers have been used previously, clean them with a solution of one part household bleach and nine parts water. Prepare a mixture of equal parts builder's sand and a peat-based potting mixture. Moisten the mixture and fill the containers. Tamp down to within 1 inch from the rims.

        Sow the seeds about 1/2-inch apart and cover with a thin layer of the potting mixture. Then, spread a thin layer of very fine gravel or coarse sand on the top to prevent rain from washing out the potting mixture and the seeds.

        • Label each container with a permanent marker to survive the winter. Water well.

        • For chilling the seeds, select a location out of direct sun, such as an unheated porch or shed (I use a metal lawnmower/tool shed on the back of my property). A place where temperatures remain between 35 and 45 degrees is ideal. If you choose a place open to the elements, cover the containers with wire screen to keep out birds and rodents.

        • Check containers periodically and water if the top of the soil feels dry. As spring approaches, you should see signs of growth. Remember: Different species will germinate at different rates. As seeds germinate, move the containers to bright but indirect sunlight. Keep an eye out for slugs, which can devour seedlings overnight.

        • When seedlings have developed their second set of leaves, divide and transplant. Use a fork to gently lift them from the original containers and “tease” them apart. Handle the seedlings by their leaves to avoid damaging the stems. After about a week, place containers of transplants in morning sunlight. Feed transplants once a week, using a liquid fertilizer diluted to half strength.

        • By late summer or fall, seedlings should be strong enough to be set out in the garden. For those that are still too small, keep them another winter in a cold frame.

        Write to Tim Morehouse, Cincinnati Enquirer, 312 Elm St., Cincinnati OH 45202. Enclose a self-addressed, stamped envelope. www.getmoregarden.com
       
       

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