The best time to plant lily seeds is during fall and early winter. Lilies planted at this time produce stems that flower at the expected time. Seeds planted late in the spring produce later-flowering stems, which may be relatively shorter than normal.
During the following winter, lilies reset and are put on standard blooming again. The important considerations in growing of lilies are good drainage and disease and weed control. A combination of sand, soil, vermicute, perlite and any kind of organic matter produces a light, airy mix that retains moisture while allowing good drainage. Heat sterilization of about 200 to 300 F for one hour is required to kill disease organisms and weed seeds when using soil or reusing planting mix.