Hybridizers have turned it into one of the most popular bedding plants. Zinnias grow to between 6 and 40 inches in height with single and double blossoms varying in diameter from less than an inch to 7 inches. The petals can be any of a wide range of colors or multicolored. Sow seeds indoors six weeks before the last frost and plant outdoors after frost danger is past as young plants are susceptible to chilling cold. They will not grow substantially until temperatures are above 50 degrees.
Zinnias are one of the easier annuals to start from seeds.
Sow the taller varieties in 3 inch peat pots because they resent transplanting. Alternatively, seeds can be sown directly outdoors when the soil has warmed sufficiently. Pinch the tops out of young plants when they are 4-6 inches high to make them bushy. Remove faded blossoms to keep them producing. Plants should be spaced 4 to 12 inches apart according to variety.