Black-eyed Susans (Rudbeckia hirta) supply your garden with a touch of sunshine yellow, offset by a deep brown center. These flowers attract butterflies and bees, making them a natural choice for a butterfly or wildflower garden. Although black-eyed Susans are hardy in U.S. Department of Agriculture plant hardiness zones 3 through 7, they only flower for a few years so they are often treated as annuals. Sow the seeds indoors six to eight weeks before the last frost date in your area.
Fill 3-inch-diameter seedling pots with a sterile potting soil to within 1/4 inch of the rim. Fill a tray with 1 inch of water, and set the pots inside. Allow the soil in the pots to absorb the water through their bottom drainage holes for 30 minutes or until the soil surface feels moist.
Set two black-eyed Susan seeds on top the soil in each pot. Press the seeds lightly with your fingertip so they are pressed into the soil but not buried. Black-eyed Susans require light to germinate.
Sprinkle the soil surface lightly with water. Slide the tray of pots into a clear plastic bag, and seal it closed. The bag retains moisture and humidity so the seeds don't require watering until after they sprout.
Place the pots in a location with bright but indirect light. Maintain a temperature between 70 and 72 degrees Fahrenheit to help speed germination. Black-eyed Susans typically require 14 days to sprout.
Remove the plastic once the seeds germinate. Set the pots in a location that receives six hours or more of daily sunlight, and water the seedlings when the soil surface feels dry. Thin each pot to one seedling once the plants produce their second set of leaves.
Transplant the black-eyed Susans to a well-drained, full sun garden bed after spring frost danger is past. Plant the seedlings at the same depth they were growing at in their pots, and space them 8 inches apart in all directions.