By E. VinjeTweet
Easy to plant from seed, growing zinnias is very rewarding with their full, rich colors and abundant blooms. Available in a wide variety of sizes, from miniatures to giants, and colors, from white to orange to pink and multicolored, zinnias will satisfy any flower-lover for several months every summer.
Zinnia is an annual warm season plant that likes full sun and a rich, well-drained soil. They are easy to grow, however, and will tolerate average to slightly poor soils. Generous amounts of compost and organic matter will improve the health of your zinnias tremendously. Keep the soil moist, but not wet.
How to Plant:
Zinnias can be started early indoors for transplanting outdoors about six to eight weeks before the last frost date, or they can be seeded directly into the flower bed after all danger of frost has passed. Sow directly into the soil and cover with about 1/4 inch of soil. Water thoroughly. Thin to 6-12 inches apart after they have sprouted.
Once established and healthy, zinnias will continue growing easily even if left unattended. Water to keep the soil moist but not wet. Zinnias will tolerate dry soil but tend to wilt in very dry conditions.
Fertilize monthly with an organic fertilizer once they have begun blooming. Pinch the spent blooms off to extend the blooming season. Mulch is a good idea and helps prevent weeds and improve aesthetics. They will not survive a hard frost or freeze.
Insects and Disease:
Zinnia is prone to fungal diseases including black spot, rust and powdery mildew. Keep the foliage dry whenever possible and keep the soil beneath the plants clean. Watch for insects or disease and treat early to prevent widespread damage.
Seed Saving Instructions:
Zinnias will cross-pollinate. Gardeners should only grow one variety at a time to save pure seed, or isolate varieties by 1/4 mile. Seeds are ready to harvest when the blooms begin to turn brown and dry. The seeds are contained in the very center. When the heads are completely dry, gently crush the heads between your hands and then carefully winnow away the chaff.