Planting day lily seeds only requires placing seeds in the ground and covering them with soil. For more controlled seed starting, follow a regimen of gathering, cooling, planting and hardening for raising day lilies from seed.
To gather day lily seeds, wait for flowering plants to form oblong, green seed pods. The pods turn brown and begin to crack, indicating that the seeds are ready for gathering. Inspect the color of the seeds to determine viability. Black seeds are healthy seeds. If the seeds are brown or white, discard them.
Before cooling the seeds, place the seeds in a container that keeps out moisture and light. Roughly a month before the intended germination date, commence cooling the seeds. Cooling the seeds is a process known as "stratification," which mimics seasonal temperatures to induce germination.
Gardeners package seeds for cooling in many different ways. The most important consideration for packaging is to keep the seeds sealed off from air and moisture. Gardeners typically use zippered plastic bags or plastic food storage containers. Place the seeds in the refrigerator for three to four weeks. Day lily seeds purchased from a nursery are typically stratified before packaging.
Plant prepared seeds in small pots filled with soil. Place the pots in an indoor location exposed to the sun. In spring, transplant young plants into garden beds.