Purple coneflowers, or echinacea, provide perennial color to your garden beds. The plants grow well in most climate zones, surviving both winter cold and summer heat. The upturned eye of the coneflower is surrounded by purple petals in summer. In winter, the eye becomes a seed head that attracts wildlife to the garden to feed while also providing interest to the winter landscape.
Coneflowers germinate when soil temperatures reach 65 to 70 degrees Fahrenheit. The seeds remain dormant until the soil becomes sufficiently warm in outdoor beds, so planting too early can delay germination. The seeds need moist soils and no light to germinate. Too much light can inhibit sprouting so the seeds don’t germinate successfully.
Starting seeds indoors ensures the seeds receive the proper conditions for successful germination. Planting seeds 1/8 inch deep in small seedling pots filled with a moistened potting mixture provides the proper medium and depth for germination. If maintaining proper soil temperatures proves difficult in normal indoor conditions, a germination heat mat under the pots helps keep the soil warm throughout. Covering the pots with a plastic bag further traps moisture in the soil and provides the proper moisture for successful germination.
Coneflowers also germinate well when seeded directly in the garden bed and established plantings generally self-sow each year. Coneflowers sown on the soil surface and covered with a 1/8-inch layer of soil germinate within 20 days if the soil remains at the right temperature. Outdoor beds dry out more quickly so a daily misting with water may be necessary to maintain the moisture in the coneflower bed.
Cold temperatures and dry soil inhibit germination or cause the young sprouts to die before they fully emerge. Keeping soils moist, but not soggy, allows the seeds to germinate quickly. Overly wet soil also favors fungal growth, which can infect and kill the seedlings once they fully emerge. Coneflowers quickly reach maturity, so over-planted beds must be thinned to approximately 18 inches apart in the first week or two after sprouting.