Lavender requires a period of cold stratification before the seeds will germinate. Ideally, plant lavender seeds in the fall, let them go through winter, and come spring, lavender plants will begin growing. These lavender plants won’t flower this first year, but after overwintering a second time the plants will be well-established and will bloom season after season, for as long as twenty years.
To speed up this process, you may trick lavender seeds into germinating by storing the seeds in the refrigerator for two to three months. To create a period of false winter, about three months before spring, put lavender seeds in a plastic bag with damp peat moss or seed starting mix. Leave alone for at least ten weeks, then remove and sow as normal. Your lavender seeds will happily germinate!
Choose a site for planting that gets full sun and drains well. Contrary to most plants, lavender thrives in poor, sandy soil. Lavender prefers desert-like conditions. When direct seeding, lightly push lavender seeds into the soil but do not cover—lavender seeds require light to germinate. Be patient, as lavender seeds take time to sprout—you may have to wait anywhere from two to four weeks for the first seeds to sprout. Once seedlings appear, water sparingly—when the foliage starts wilting, the plant is signaling it needs a drink.