Yes — Strong Match
zinnia is grown as an annual, so season length decides it here, not a winter zone — and Minnesota's typical season runs ~174 frost-free days against the ~60 zinnia needs.
Sow by about Aug 9
Zinnia is grown as an annual, so what decides it here is season length, not a winter zone. It needs about 60 frost-free days and a typical Minnesota season runs ~174 frost-free days, leaving 114 days of slack. That is room to sow as late as about Aug 9 and still finish before the usual first freeze (Oct 13).
Want more weeks at either end of that window? How to buy the weeks →
60 frost-free days required against Minnesota’s ~174-day season. NOAA Regional Climate Centers ACIS 1991-2020 (28°F killing freeze), state median across counties, via stateClimateData.ts.
Zinnia in Minnesota — the short answer
Zinnia in Minnesota: full sun, against a state median of ~174 frost-free days.
- Minnesota zones
- 3a-5a
- USDA PHZM 2023
- Frost window
- Apr 19 - Apr 30 – Oct 10 - Oct 17
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 137 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 65 days
- Growable Ground Plant Database
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.
Your yard isn't the whole zone.
Zinnia is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Minnesota site runs ~174 frost-free days, but that is a state median, not your yard: slope, trees, and low spots move the last-frost date across a single parcel. Enter your address and we'll score zinnia against your land's actual frost dates, sun, and soil.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Minnesota is not one climate
A single Minnesota answer averages 87 counties whose growing seasons are 62 days apart — from 137 frost-free days in Lake County to 199 in Ramsey County. Which end of that your land sits nearer changes what zinnia can finish before the first hard freeze.
The middle half of 87 counties runs 162–181 days, with a median of 174 days — a 62-day span end to end.
Measured across 87 Minnesota counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.
Zone Comparison
Zinnia Needs
- USDA Zones: Data pending
- Frost-Free Days: 60+
- Sun: Full Sun
- Mature size: 3 ft tall
- Picking window: ~120 days of harvest
- Drought tolerance: Medium
Minnesota Has
- USDA Zones: 3a-5a
- Last Hard Freeze (28°F): Apr 19 - Apr 30
- First Hard Freeze (28°F): Oct 10 - Oct 17
- Annual Rainfall: 19-34 inches
- Common Soils: Prairie loam, Clay, Sandy outwash
Preferred Soil pH
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Zinnia in Minnesota
The frost window
Across Minnesota, the last spring hard freeze (28°F) clears between Apr 19 and Apr 30, and the first fall hard freeze lands between Oct 10 and Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 163-day window you can count on — up to 181 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.
Frost tenderness
Zinnia is frost-tender — FAO ECOCROP puts its killing temperature at 32°F — so set plants out two to three weeks PAST your local last hard freeze, not on it and not on the state's earliest date. The 28°F marker above is when killing freezes stop, not when light frost does. That is the point where cold damages growing tissue, not a winter-survival floor — an established perennial comes through far colder while dormant, which is what its hardiness zone tells you.
When to start the seed
Those dates are when zinnia goes out, not when it starts. It is sown under cover about 4 weeks ahead, so counting back from Minnesota's late-side last freeze of Apr 30 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
Days to maturity vs. the window
At 65 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 98 days to spare even in Minnesota's tightest freeze scenario — room for a later start or a second sowing.
Timing tuned to sub-state frost dates — Lake County, not the statewide average.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Growing Season Fit
Frost-free days
Zinnia wants 60+ frost-free days; a typical Minnesota site sees ~174 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Zinnia needs ~800 GDD (base 50°F) to ripen. The state median runs ~1920 GDD (from PRISM 1991-2020 climate normals), so Minnesota's typical season clears that easily.
GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.
Soil + Drainage Fit
Zinnia likes near-neutral soil (pH 5.5-7.5). That's the common-ground band across Minnesota's prairie loam and clay — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6 and 7 — worth knowing before you decide whether a Minnesota soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Minnesota site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
SSURGO maps about 34.6% of Minnesota as poorly or somewhat-poorly drained, and the class flips parcel to parcel. Zinnia sits mid-range for drought tolerance, so either extreme can cost you — your soil map unit, not the state average, is the real answer.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Minnesota soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Zinnia in Minnesota
Zone compatibility tells you about winter cold survival — but Minnesota growers also need to think about:
Extreme cold (zone 3a: -40F) limits many species
Short growing season (100-140 frost-free days)
Heavy clay soils in the Red River Valley
Growing zinnia here specifically
Zinnia likes pH 5.5–7.5 and its growing tissue burns around 32°F (FAO ECOCROP), yet neither saves it from wet feet — SSURGO maps about 34.6% of Minnesota poorly-drained, where its roots sit and rot.
Set zinnia high on bermed, grit-amended ground so winter and storm water drain away from the roots. How to handle it →
What to actually do about these — and the constraints that apply to every Minnesota grower, not just zinnia — is covered on the Minnesota growing guide.
Timing shifts within Minnesota
Minnesota isn't one climate. In Lake County, the last hard freeze (28°F) holds until about May 14 — roughly 23 days later than the recorded state median — so plant zinnia to your county's window, not the statewide date.
Zinnia needs about 60 days of frost-free season to complete its cycle. Even Lake County — Minnesota’s shortest season at 137 frost-free days — clears that by 77 days, so season length isn’t the constraint anywhere in Minnesota. What varies is your own parcel.
Across Minnesota’s 87 counties the frost-free season runs from 137 days in Lake County to 199 days in Ramsey County — a spread of 62 days, which is why a single statewide planting date misleads. The median Minnesota county sees 174 frost-free days, leaving zinnia about 114 days of slack on a typical parcel — room for a second sowing where the season runs long.
County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Zinnia's 60-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Pollinator + Wildlife Value
Zinnia draws honeybees, native bees, butterflies, and hummingbirds (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, zinnia can only work that bloom inside Minnesota's frost window — roughly 174 days, opening after the last 28°F freeze (Apr 19 - Apr 30) and closing at the first (Oct 10 - Oct 17), per NOAA Regional Climate Centers ACIS, 1991-2020.
Recommended Zinnia Varieties for Minnesota
Minnesota publishes no state variety trial for zinnia, so we won't invent a "best for Minnesota" list. Choose types rated to your USDA hardiness zone (3a-5a), and confirm winter survival and drainage against your own parcel.
Minnesota Cooperative Extension
For Minnesota-specific cultivar recommendations, planting calendars, and pest pressure for zinnia, the canonical source is University of Minnesota Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Zinnia native to Minnesota?
No — the USDA PLANTS Database lists Zinnia as introduced rather than native in the Lower 48, so it is not part of Minnesota's native flora. It grows here as a garden plant; pairing it with a few Minnesota natives keeps local pollinators fed too.
Looking for plants that belong here? The Minnesota growing guide lists USDA-documented natives for the state.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Zinnia in Minnesota
When can I plant Zinnia in Minnesota?
Minnesota's last spring hard freeze (28°F) clears between Apr 19 and Apr 30, and the first fall hard freeze lands between Oct 10 and Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020). Zinnia is frost-tender — its killing temperature is 32°F (FAO ECOCROP — the point where cold damages growing tissue, not a winter-survival floor) — so wait two to three weeks past your site's last hard freeze, when light frost has also stopped, before planting out.
Can Zinnia mature before first frost in Minnesota?
Yes — Zinnia matures in 65 days (Growable Ground Plant Database), and Minnesota's dependable hard-freeze-free window runs 163 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 98 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.
What hardiness zone is Zinnia grown in across Minnesota?
Minnesota spans USDA hardiness zones 3a-5a (USDA ARS PHZM 2023). Zinnia carries a range of zones Data pending, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Minnesota site have?
A typical Minnesota site sees ~174 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Zinnia needs 60+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Lake, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Zinnia native to Minnesota?
No — the USDA PLANTS Database lists Zinnia as introduced rather than native in the Lower 48, so it is not part of Minnesota's native flora. It grows here as a garden plant; pairing it with a few Minnesota natives keeps local pollinators fed too.
How should I amend the soil for Zinnia in Minnesota?
Zinnia prefers pH 5.5-7.5 and well (dry spells) drainage (Growable Ground Plant Database). That sits in the common-ground band across Minnesota soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Zinnia actually grow on my specific land in Minnesota?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores zinnia against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Minnesota
State-level data is a sketch. Your Growable Ground report scores zinnia against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Minnesota zinnia averages can't show:
We read public map data around Minnesota — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Minnesota zinnia average
Explore More
Growing guides for zinnia
Explore Minnesota county by county
Minnesota carries 87 counties with their own USDA zone — a sample of the growing pages for zinnia there:
Where else zinnia grows
Zinnia's zone band crosses state lines — these are the states closest to Minnesota in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in Minnesota
Minnesota has a growing page for 747 plants — a rotating sample of the rest of the shelf.
Analysis by the Growable Ground research team, grounded in USDA PLANTS, USDA NRCS SSURGO, NOAA Climate Normals (1991-2020), and named Cooperative Extension sources. How we know →
Cite this dataset
Kirchick, M. (2026). Growable Ground Plant Database [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21435643
Licensed CC BY-NC 4.0. DOI 10.5281/zenodo.21435643
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