Prompted by the arrival of post-holiday catalogs in January, gardeners get the itch to break out the peat and vermiculite and start seeds for this summer's garden. Annuals like zinnias, marigolds and tomatoes are fairly simple to start indoors, but starting perennials indoors requires a more sophisticated approach. These long-lived plants may require stratification, scarification or double dormancy before successful germination. Find out which seeds have special needs to avoid disappointment and produce seedlings for spring transplanting on the first try.
Begin a chart with columns for names of perennials and the number of days each one needs to germinate. Compute planting dates by counting that gestation period back from the last average frost date in your area; the date is available on the USDA growing zone map. Enter the estimated date of planting in a third column.
Make two columns labeled stratify and scarify. Read seed packets or consult a perennial database to find out which seeds need special treatment. Enter dates that fall 90 days before the start of the gestation period for stratification; you'll only need a few days for scarification. You now have a start date for each variety.
Stratify seeds by sealing them in a plastic bag or container filled with moist, never wet, sterile planting medium. Choose a loose material like peat moss or vermiculite for best results and inspect the seeds for signs of germination every few weeks. Plant seeds after 90 days or at the first signs of green. Repeat refrigeration for seeds that need double dormancy.
Scarify thick-coated seeds by nicking them with a paring knife or file. Some instructions will specify hot water scarification; place seeds in 170 to 210 degree Fahrenheit water, let it cool and allow them to soak for up to a day. Whichever method is used, plant the seeds immediately unless they need stratification, too.
Plant seeds in pots, cells or flats filled with sterile medium. Keep the soil moist and the containers out of direct sunlight. A cover of clear plastic works like a greenhouse; remove it when the seedlings break the surface to minimize damping off, a fungal condition that fells seedlings.