Snapdragons are tender perennials that are usually grown as annuals. They need cool temperatures to grow well and are usually planted in the spring in USDA zone 7 and north, or in the spring in USDA zone 7 and south where they are treated like pansies. Since snapdragons are self-pollinated, different varieties do not usually cross. If crosses do occur dark colors dominate with yellow being recessive. A major problem of snapdragons is rust, a disease caused by the fungus Puccinia anthirrihi, and resistance to disease should guide the selection of plants as a seed source. There are many named cultivars of snapdragons varying in color, height, and disease resistance but because they are hybrids many do not breed true, tetraploid snapdragons being the exception. Snapdragons like full sun, and moist, well-drained soil, but tolerate light shade and some dryness.
Snapdragon seeds are sown outdoors only in warm areas where they can be planted in cold frames in late summer and early fall. Indoor sowing is started at least eight to ten weeks before the last frost.
Directions for Indoor Sowing:
1. To speed germination, press seed into moist soil and refrigerate for two days. The seed need light to germinate so do not cover the seeds.
2. Place in an area where temperatures are between 70 and 75 F.
3. Water seeds only from the bottom to avoid damping off. Germination should occur in seven to twenty one days under optimal conditions
4. Hardenoff and transplant to the garden after all danger of frost is past spacing dwarf varieties six inches apart and taller varieties twelve inches apart.