When to plant Zinnia
Computed from land-grant Extension planting-window rules (cited below), localized to real ZIP-level median frost dates, not a single national guess. These are national-generic rules by hardiness class; individual state Extension offices layer their own regional adjustment on top (earlier in the Deep South, later in the Upper Midwest). Enter your ZIP for your own dates, or read the four representative locations below.
Planting windows and crop timing here are computed from USDA/NOAA climate data and the university extension sources cited below, not a site visit or soil test. Treat this as a starting point: local conditions vary, and a local nursery or extension office can advise on your exact site. See our full Disclaimer.
Representative timing, by climate band
When to plant Zinnia in four US climates
Each column is the most nursery-dense location in our directory within that USDA zone band, computed from that location's own real median frost dates, not a made-up example.
| Stage |
Zones 1-5 (cold winters)
Fort Plain, NY |
Zones 6-7 (temperate)
McMinnville, TN |
Zones 8-9 (warm)
Apopka, FL |
Zones 10-13 (hot, frost rare or absent)
Loxahatchee, FL |
|---|---|---|---|---|
| Start seed indoors | Not available | Not available | Not available | – |
| Direct-sow outside | May 6–May 20 | Apr 7–Apr 21 | Feb 24–Mar 10 | – |
| Transplant outside | Not available | Not available | Not available | – |
| Fall planting | Not available | Not available | Not available | – |
| Expected harvest | Jul 1–Aug 12 | Jun 2–Jul 14 | Apr 21–Jun 2 | – |
Zones 10-13 (hot, frost rare or absent) (Loxahatchee, FL): Frost is rare here (about 359 frost-free days a year); most years see little or no hard freeze. This is a tender crop. In climates like this one, tender and very-tender crops typically go in before the hottest months arrive, not on a frost-relative schedule.
Zinnia is a tender annual, consistently classified that way across Clemson Cooperative Extension's dedicated Zinnia factsheet (HGIC 1149), its Growing Annuals factsheet (HGIC 1152), and NC State Extension's Growing Annual Flowers guide, which tells tender annuals to wait two to three weeks after the last spring frost.
Bloom timing, eight to twelve weeks, or 56 to 84 days, after direct sowing, and an ideal soil and air temperature near 70°F, both come directly from Clemson's HGIC 1149 factsheet.
Zinnia is grown from seed, direct-sown once soil has warmed to that mark, though started flats are also common at the nursery for gardeners who want blooms sooner.
Frost hardiness
Tender. Damaged or killed by frost. Plant after the last frost date.
Minimum soil temperature
70°F
For direct sowing/germination, where an Extension source stated it.
Days to maturity
56–84
Sourcing notes
Tender annual, consistent across Clemson (HGIC 1149 + Growing Annuals HGIC 1152) and NC State's Growing Annual Flowers (tender annuals "wait two to three weeks after last spring frost," accessed via search snippet after direct fetch of content.ces.ncsu.edu/growing-annual-flowers returned HTTP 403). Bloom timing (8-12 weeks = 56-84 days after direct sowing) and ideal soil/air temp ~70F both explicitly stated by Clemson HGIC 1149.
Related crops
Growing zones for this crop
Nurseries near these locations
See everything with an open window this month →
Sources
- Clemson Cooperative Extension Home & Garden Information Center, Growing Annuals (HGIC 1152) (accessed 2026-08-04)
- Clemson Cooperative Extension Home & Garden Information Center, How to Grow Zinnias: The Best Varieties & Care Tips (HGIC 1149) (accessed 2026-08-04)
- NC State Extension Publications, Growing Annual Flowers (accessed 2026-08-04)