How to Grow Zinnia Seed

Showy blossoms of zinnias.

Zinnias are annual flowering plants that produce some of the showiest and most colorful blossoms imaginable. These cheery plants were developed from a wildflower found growing in Mexico. For the home gardener, zinnias make for hardy background plants, and they also grow well in tubs and barrels. Since zinnias do not take well to transplanting, sow the seeds directly where you wish to grow them.

Things You'll Need

• Zinnia seeds
• Shovel
• Hoe
• Rake
• Amendment
• Trowel
• Garden stakes
• Fertilizer

Instructions

Preparing the Soil and Planting the Seeds

1. Find a suitable planting site for the zinnias. Ideally the location should be in full sun and 3 to 4 feet from other vegetation. This ensures adequate ventilation and prevents powdery mildew from forming on the plants. Plan on planting zinnia seeds in mid-to-late spring, from March through April.

2. Weed the planting area thoroughly using a short- or long-handled garden hoe.

3. Dig up the soil in the planting area to a depth of about 18 inches. If any garden litter is found such as rocks, sticks or roots, pick them out and dispose of them.

4. Spread out a 3- or 4-inch layer of leaf mold, aged compost or well-rotted cow manure over the topsoil in the planting area. Use a shovel or fork to work the amendment 14 to 16 inches into the soil.

5. Smooth the topsoil out using a metal rake.

6. Create 1/2-inch deep furrows in the planting area. Keep each furrow between 12 and 18 inches, depending on the variety of zinnia you are growing.

7. Plant one to two zinnia seeds every 6 to 8 inches. Cover the seeds with no more than 1/2 inch of soil.

8. Sprinkle the entire area with a light mist of water, making sure not to displace any seeds. Keep the seed bed moist but not sopping wet. Germination will begin in about seven to 10 days when the temperature is between 70 and 75 degrees Fahrenheit.

Caring for Zinnias

1. Fertilize zinnia once every three to four weeks using a balanced 12-12-12 or 10-10-10 fertilizer. Application rates vary by manufacturer so make sure to read the directions provided on the label so you know how much fertilizer to spread.

2. Water zinnias sparingly, one to two times a week. Avoid letting water strike the foliage of the zinnias. Too much moisture causes powdery mildew, an unsightly condition that destroys zinnias.

3. Remove faded and dead blossoms, a process usually referred to as deadheading, using a pair of snips or scissors.

4. Push in 12- to 16-inch high garden stakes, keeping each about 3 inches from the stem of the zinnias. Do this if you are growing taller zinnia varieties such as Liliput or Envy Double.

References

• Cornell University: Growing Zinnias
• Floridata.com: Zinnias