Turn over the soil in the area you want to plant your zinnias and work in 2 or 3 inches of compost or peat moss to help improve soil fertility and drainage. Plant the seeds only about ¼” – ½” deep and you should see seedlings sprout in four to seven days. Once the seedlings reach about 3” tall, thin them to maximize air circulation, and prevent powdery mildew. The dwarf varieties, reaching a height of 1 to 1 ½ feet, should be planted or thinned to about 9” apart, while the taller 3-feet varieties should be spaced about 1 foot apart.
