Updated: Sep 25, 2019
Zinnia are my all time favorite flowers to grow from seed. Zinnia are super easy to grow, prolific, and come in a stunning variety of colors, shapes, and sizes. The only downside to zinnias is they have a longer “days to maturity” than some flowers and only really get to pumping out blooms in later summer (late July through August and if you are lucky with a late first frost, even into September or October). In an effort to get more flowers from my zinnia earlier and for longer, I always start my zinnias both indoors and direct sow. Honestly though, starting them indoors is more to satisfy my own desire to get my hands dirty as early as possible than anything else. I’m pretty sure all of my pre-work starting zinnia indoors does next to nothing to jump start blooms as by August I can’t tell a difference between the ones started inside in March and the ones direct sowed in May. Additionally, zinnias grown in indirect light or in the greenhouse do not develop as vibrant colors as those grown outdoors in direct light.
Site: Full sun
Days to Maturity: 75-90 days
Height : type dependent, up to 36” tall
Plant Spacing: 9-12 inches
Start indoors: 4-6 weeks before last frost, start seeds in trays indoors. Transplant outdoors only after all danger of frost has passed.
Direct Sow: Can direct sow after all danger of frost has passed.
Pinch: when 10” tall
Harvest: Harvest in full bloom only once stem remains rigid when shaken. Will last up to 10 days in water with flower food.
Where to Buy:
For trendy and newer color choices but that tend to sell out quickly:
For super high quality, brighter and more traditional color strains. The only drawback of purchasing seeds from this site is the $10 per order shipping fee: