HOW TO SOW
Zinnias are heat loving, summer blooming flowers.
They do not like cold temperatures and can’t handle frost, so do not try to plant them too early in the season. They grow quickly when the soil warms up and begin to bloom around early/mid July.
Transplants or Direct Sow?
Zinnias are versatile and can be transplanted or direct sown.
Transplants are fine, but make sure the transplants are only a few weeks old (3-4 weeks). Larger, older transplants tend to be “root bound” and will be permanently stunted in their growth and vigor.
Personally, I find Zinnias grow faster, and are more productive and healthier when they are direct sown.
I’ve done trials, planting 4 week old transplants on the same day as direct sowing seeds. Within 2 months, the direct sown plants were BETTER than the transplanted plants.
You might as well save yourself some time and space, and simply direct sow the seeds!
To ensure I have blooms all summer, I usually so 2-3 sowings in the spring, spaced 2-3 weeks apart. For example, I start some seeds indoors in the spring. When they are ready to be transplanted out into the beds, I will also direct sow some seeds in another bed at the some time. 2-3 weeks later, I will direct sow more seeds.
PLANT SPACING
For cut flower use, Zinnias can be grown anywhere from 6-12” apart.
Closer spacing encourages longer, straighter stems… but too close and you risk increased disease problems. You’ll have to experiment and find out what works in your area!
