Lavender can be purchased in gallon sized containers at nurseries and transplanted directly into your garden anytime of year when the ground is not frozen. You can also take cuttings from lavender plants and remove the leaves on the lower third of a 7 inch cutting, then insert this stem into the soil and keep soil slightly moist. Roots will form to make new lavender plants. Planting lavender by seed is a bit tricky. Not sure where you garden but my best advice is to contact a local lavender farm to see what varieties work best in your region and get recommendations on when to take cuttings and prune plants after they flower. Welcome to a lavender life, Keep growing, Marianne Binetti