Jason Kafka says zinnias perform better in tunnels than in the field. With the extra heat they get so big that “they think they are in New Jersey.”
Culture: Sow in a sunny spot after last frost, or start indoors for earlier blooms. They need good drainage and like heat. Cut when flowers are almost fully mature, just before pollen starts to form. Deadhead to continue production.
Germinates 3–5 days at 80–85°, more slowly at cooler temperatures. Grow on at 70° days, 60–65° at night. Temperatures below 60° delay flowering and may induce chlorosis. Space at 9–12".
All flowers are annuals except where noted. All flowers are open-pollinated except where noted.
Days in parentheses after a variety indicate days to first bloom.