Zinnia are warm weather annuals native to Central America, Mexico, and southwestern US. They are grown for their intensely colored flowers which are held singly on long stems. Flowers may be buttons, pompoms, cactus-flowered, or dahlia-flowered and range in color to include gold, red, orange, pink, lavender, yellow and white. The plants are easy to grow from seed so are a good choice for a beginner. Zinnias are cross pollinated by insects so seed savers should plant only one variety at a time to maintain stain purity. Many of the available zinnia seeds are hybrids and will not breed true. Zinnias like full sun, and organically rich, moist but well-drained soil.
Zinnia seedlings resent transplanting and double forms may revert to single forms when transplanted. Outdoor sowing is preferable but seed can be started indoors.
Directions for Outdoor Sowing:
1. After the last frost and when the soil is warm sow seeds directly in the soil, covering ¼ inch. Seeds germinate in two to seven days at temperatures of 70-80 F.
2. Thin to six to nine inches for dwarf varieties, ten to twelve inches for medium varieties, and fifteen to eighteen inches for tall varieties.
Directions for Indoor Sowing:
1. Four to six weeks before the last frost plant 2-3 seeds in peat pots covering ¼ inch.
2. Place in an area that is 70-80 F. Seeds germinate in two to seven days under optimal temperatures.
3. Water from the bottom to avoid damping off.
4. Harden off.
5. Transplant out doors after the last frost spacing dwarf varieties six to nine inches apart, medium varieties ten to twelve inches apart, and tall varieties fifteen to eighteen inches apart.