Yes — Strong Match
geranium is grown as an annual, so season length decides it here, not a winter zone — and Maine's typical season runs ~182 frost-free days against the ~95 geranium needs.
Sow by about Jul 18
Geranium is grown as an annual, so what decides it here is season length, not a winter zone. It needs about 95 days from sowing to finish and a typical Maine season runs ~182 frost-free days, leaving 87 days of slack. That is room to sow as late as about Jul 18 and still finish before the usual first freeze (Oct 21).
Want more weeks at either end of that window? How to buy the weeks →
95 days to maturity against Maine’s ~182-day season. NOAA Regional Climate Centers ACIS 1991-2020 (28°F killing freeze), state median across counties, via stateClimateData.ts.
Geranium in Maine — the short answer
Geranium in Maine: hardy in zones 10–11, part sun, against a state median of ~182 frost-free days.
- Plant zones
- Grown as an annual — see the growing season
- Growing season, not a hardiness zone
- Maine zones
- 3b-7a
- USDA PHZM 2023
- Frost window
- Apr 16 - May 3 – Oct 10 - Oct 24
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 143 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 95 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.
Geranium is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Maine site runs ~182 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 geranium 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.
No card required · your parcel report in seconds — read in full free for your first 14 days
Maine is not one climate
A single Maine answer averages 16 counties whose growing seasons are 79 days apart — from 143 frost-free days in Franklin County to 222 in Knox County. Which end of that your land sits nearer changes what geranium can finish before the first hard freeze.
The middle half of 16 counties runs 154–191 days, with a median of 178 days — a 79-day span end to end.
Measured across 16 Maine 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
Geranium Needs
- USDA Zones: 10-11
- Sun: Part Sun
- Mature size: 1.5 ft tall
- Picking window: ~150 days of harvest
- Drought tolerance: Medium
Maine Has
- USDA Zones: 3b-7a
- Last Hard Freeze (28°F): Apr 16 - May 3
- First Hard Freeze (28°F): Oct 10 - Oct 24
- Annual Rainfall: 36-50 inches
- Common Soils: Glacial till, Sandy loam, Rocky loam
Plant Zone Range (zones 10-11)
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 Geranium in Maine
The frost window
Across Maine, the last spring hard freeze (28°F) clears between Apr 16 and May 3, and the first fall hard freeze lands between Oct 10 and Oct 24 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 160-day window you can count on — up to 191 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.
When to start the seed
Those dates are when geranium goes out, not when it starts. It is sown under cover about 14 weeks ahead, so counting back from Maine's late-side last freeze of May 3 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 95 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 65 days to spare even in Maine's tightest freeze scenario — room for a later start or a second sowing.
Timing tuned to sub-state frost dates — Piscataquis 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
Days to maturity
Geranium matures in ~95 days (Growable Ground Plant Database). A typical Maine site has ~182 frost-free days, so plenty of room for a second succession.
Growing degree days
Geranium needs ~1000 GDD (base 50°F) to ripen. The state median runs ~1450 GDD (from PRISM 1991-2020 climate normals), so Maine'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
Drainage matters: this plant wants well (dry spells). If your Maine site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Maine's soils run mostly fine sandy loam, but SSURGO maps the series, texture, and drainage under your exact parcel. What matters for geranium is the horizon its roots actually work, not the surface. That map unit, not the state average, decides how geranium performs.
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. Maine soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Geranium in Maine
Zone compatibility tells you about winter cold survival — but Maine growers also need to think about:
Very short growing season (100-140 frost-free days)
Rocky glacial soils require significant clearing
Harsh winters with heavy snow and ice
What to actually do about these — and the constraints that apply to every Maine grower, not just geranium — is covered on the Maine growing guide.
Timing shifts within Maine
Maine isn't one climate. In Piscataquis County, the last hard freeze (28°F) holds until about May 15 — roughly 23 days later than the recorded state median — so plant geranium to your county's window, not the statewide date.
Geranium needs about 95 days of frost-free season from planting to harvest. Even Franklin County — Maine’s shortest season at 143 frost-free days — clears that by 48 days, so season length isn’t the constraint anywhere in Maine. What varies is your own parcel.
Across Maine’s 16 counties the frost-free season runs from 143 days in Franklin County to 222 days in Knox County — a spread of 79 days, which is why a single statewide planting date misleads. The median Maine county sees 182 frost-free days, leaving geranium about 87 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"). Geranium's 95-day requirement: USDA PLANTS / Growable Ground plant database (days to maturity). A parcel report resolves your address's own frost dates.
Pollinator + Wildlife Value
Geranium draws honeybees and butterflies (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, geranium can only work that bloom inside Maine's frost window — roughly 182 days, opening after the last 28°F freeze (Apr 16 - May 3) and closing at the first (Oct 10 - Oct 24), per NOAA Regional Climate Centers ACIS, 1991-2020.
Good to Know Before You Plant Geranium
Geranium is listed as toxic to dogs, cats (all) at a mild level (ASPCA). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear. Worth knowing for placement: in Maine this is a one-season plant and the first hard freeze (Oct 10 - Oct 24) takes it down, so the exposure above is a summer-long one rather than something standing in the bed all year.
Recommended Geranium Varieties for Maine
Maine publishes no state variety trial for geranium, so we won't invent a "best for Maine" list. Choose types rated to your USDA hardiness zone (3b-7a), and confirm winter survival and drainage against your own parcel.
Maine Cooperative Extension
For Maine-specific cultivar recommendations, planting calendars, and pest pressure for geranium, the canonical source is UMaine Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Geranium in Maine
When can I plant Geranium in Maine?
Maine's last spring hard freeze (28°F) clears between Apr 16 and May 3, and the first fall hard freeze lands between Oct 10 and Oct 24 (NOAA Regional Climate Centers ACIS, 1991-2020). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.
Can Geranium mature before first frost in Maine?
Yes — Geranium matures in 95 days (Growable Ground Plant Database), and Maine's dependable hard-freeze-free window runs 160 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 65 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 Geranium grown in across Maine?
Maine spans USDA hardiness zones 3b-7a (USDA ARS PHZM 2023). Geranium carries a range of zones 10-11, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Maine site have?
A typical Maine site sees ~182 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Geranium should be matched against that window, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Piscataquis, the freeze-free season runs shorter than the state average, so verify your own county's window.
Will Geranium actually grow on my specific land in Maine?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores geranium 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 Maine
State-level data is a sketch. Your Growable Ground report scores geranium against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Maine geranium averages can't show:
We read public map data around Maine — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Maine geranium average
Explore More
Growing guides for geranium
Explore Maine county by county
Maine carries 16 counties with their own USDA zone — a sample of the growing pages for geranium there:
Where else geranium grows
Geranium's zone band crosses state lines — these are the states closest to Maine 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 Maine
Maine has a growing page for 807 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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