Choose planting locations that offer full sunlight and well-draining soil. Purple coneflowers, while somewhat drought-tolerant, have better success in soil that retains some moisture.
Work 3 to 5 inches of organic compost into the existing soil to a depth of at least 4 to 6 inches, using a rake or shovel. If soil is heavy clay, add 1 to 2 inches of coarse sand along with the compost to improve drainage. The Alabama Cooperative Extension System recommends adding slow-release 12-6-6 fertilizer with the other amendments, at a rate of 2 lbs. per every 100 square feet of planting space.
Sow seeds at a depth of 1/8 inch, spaced at least 12 to 24 inches apart.
Insert a toothpick or straw close to each seed to mark its location. The marker allows you to detect which plants are the purple coneflower seedlings and which are weeds that need to be removed.
Cover seeds with a thin layer of soil and water gently to set them in place. Germination takes from 15 to 30 days in soil that consistently remains at 70 degrees Fahrenheit or warmer.
Keep soil moist but not waterlogged during the germination period. Water the soil, not the plant, to keep diseases and insects at bay.
Add 2 to 3 inches of mulch to the beds once the coneflowers have sprouted and develop at least two sets of true leaves. Mulch helps the soil to retain moisture and prevents weed formation.