Grow healthy perennials from seed in 5 easy steps

While many perennials are readily available at your local garden centre, many can be grown from seed. Here's how:

• Sow seeds in mid to late winter in a greenhouse or under lights.
• Window light is seldom adequate.
• When the weather warms up, sow seeds in a cold frame or sheltered bed.

• When sowing small quantities of seeds indoors, the simplest method is to plant only one kind in a pot.
• Fill the pot to about one centimetre (half an inch) below its rim with a commercial seed-starting mixture, or your own sterilized formula. Level, firm gently, water with a fine spray and let drain.
• Sprinkle the seeds evenly but thinly over the surface. Cover with a three-millimetre layer of starting medium. Leave fine seeds uncovered.
• When seedlings are large enough to handle easily, transplant to a flat pot filled with sterilized soil, and space three to five centimetres (one to two inches) apart.

• Cover seed containers with a pane of glass or a plastic bag. This helps retain moisture and warmth for germination.
• Keep the container out of the sun to avoid excessive heat.
• Most seeds germinate at 18° to 21°C.
• Depending on the kind, seedlings should appear in about one to three weeks. When they do, remove the glass or plastic covering.
• Give them all the sun available to prevent weak, spindly growth.
• As seedlings become crowded, pot individually.

• Before setting the seedlings out, acclimate them to outdoor conditions by putting them in a cold frame or sheltered spot in the garden.
• Set pots or flats on the surface of the soil, and lightly shade for a few days. Then, gradually let in more air and light.
• Later, transplant to an out-of-the-way bed for further growth.
• In late summer of the same year, plant in permanent positions, or wait until the following spring.

• For an early start in cold climates, outdoor seed sowing is best done in a heated frame.
• A soil-heating cable set for 18°C is best. In an unheated frame, sow about six weeks prior to the last spring frost.
• Prepare soil in frame by adding peat moss or perlite, so that it won't crust over and deter the seedlings from coming out.
• Sow seeds shallowly in rows or in pots as previously described. Shade the frame with burlap until seeds germinate. Then, give full light, ventilation and moisture.
• Transplant as needed into well-spaced rows or pots in the cold frame, and then later to the garden.

Many of our best-loved flowers are perennials that spring up afresh year after year. With the right care early in their lives, they can make outstanding features in borders, and provide plenty of colour for your home garden.