By Anne Petelo, master gardener, Denver County office of Colorado State University Cooperative Extension
Sowing perennial seeds indoors for outdoor spring planting is fun and rewarding. You need only minimal materials, and seeds are certainly less expensive than purchased transplants. Another advantage to growing your own is the wide variety of seed available for any preference, soil, climate and location.
Use polystyrene or plastic cups with small holes punched in the bottom for drainage. Seed starting trays also are available at any garden center.
After filling the containers with a lightweight potting mix, refer to the back of the seed packet for the planting depth. buried seeds germinate poorly so stick to the one-eighth to one-half inch depth recommended for most seeds. Water thoroughly.
Seed starting trays come with a plastic lid to retain moisture in the soil. Placing a plastic bag over the top of cups accomplishes the same thing.
Place the seed starting containers in a location where temperatures will remain at 65-70 degrees. Flats placed in cookie sheets on top of a gas stove kept warm by a pilot light will maintain the desirable warm soil temperature for seed germination.
After seedlings grow their initial seed leaves and then first true leaves, they're ready for thinning. Eliminate weaklings and transplant seedlings; this will free space in flats or additional containers. With enough space so developing leaves do not touch the leaves of neighboring plants, strong roots develop for future transplanting to the garden.
A week before planting outdoors, harden off by setting plants, outside in a protected spot for a few hours, then return them indoors. Gradually lengthen the time of outdoor exposure. This will toughen leaves and stems so plants can survive their permanent move outdoors.
Six perennial plants and one biennial plant that are easy to start from seed include:
For herb lovers, clary sage (biennial) and broadleaf sage are good bets. Biennials overwinter and go to seed the second season.
Clary sage has fragrant silvery leaves and rosy flower spikes that attract hummingbirds. The plant performs will in dry, sandy soil but be aware of its self-sowing habit. Place it where you don't mind additional plants popping up.
Broadleaf sage germinates in 14-21 days. It grows to 2 feet in the garden. Harvest leaves for cooking after plants are well-established.
For nonstop summer to fall color, try gaillardia or blanketflower. If spent blooms are removed or deadheaded, it blooms all summer. It performs best in full sun and will tolerate dry soils and neglect once established. Seeds germinate in 15-20 days and light aids germination.
Tritoma torch lily, also known as red hot poker,is another heat-and-drought tolerant perennial. Be sure to allow ample space for the 4-foot blooms. Seeds germinate in 10-20 days.
Pyrethrum painted daisies bear pink, white or lavender blooms on graceful stems ideal for cutting from April through June. Seeds require 20 to 25 days for germination. For a shorter daisy, try Silver Princess shasta daisy. A tamer version of the species, the white blooms with yellow centers cover the petite plants in early summer. Seeds require light for germination in 14 days.
For a different look in the garden, try an ornamental grass. Twelve-to-18 inch blue fescue adds blue leaves to the summer garden and tan seed heads for interest in fall and winter.
These perennial seeds are easy to start and the plants all perform well in along Colorado"s Front Range. A lovely garden can indeed be achieved inexpensively with only a little patience in raising your own plants from seed.
Photo: Judy Sedbrook
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010