St. Marys, Georgia, sits in USDA hardiness zone 9a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Growers here do well with artichoke, fig, california poppy, and cabbage — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in St. Marys, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single St. Marys lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around St. Marys — soil, climate, flood, and parcel records. How we handle your address.
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St. Marys — the short answer
St. Marys, Georgia: USDA zone 9a, about 303 days between hard freezes, across 16K acres of city.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 15
- Camden County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 15
- Camden County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~303
- Camden County normal — NOAA 1991–2020, nearest to this town
- City area
- 16K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Camden County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9a is St. Marys's average, not your lot's — a low corner or a tree line moves it. Against St. Marys's 303-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in St. Marys
Each reading below is measured for St. Marys itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsSt. Marys runs about 303 days between hard freezes (read from Camden County, the closest normal to St. Marys) — close to year-round growing.
Frost is rarely the limit here; winter plantings are as real as summer ones, and the harder question is which crops shrug off the summer heat.
Grow cool-season crops through the mild winter, and choose heat-tolerant varieties for the summer beds.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredSt. Marys sits in USDA hardiness zone 9a.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country St. Marys is in
St. Marys sits in the Southern Coastal Plain — EPA Level III, inside the wider Eastern Temperate Forests. That is read at St. Marys's own centroid rather than borrowed from Camden County.
What Grows in St. Marys
Every plant below cleared St. Marys's own zone 9a and its 303-day season. Each card opens that plant's Georgia profile. How we score.
Is it too late to plant in St. Marys?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Jan 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 15 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 15 — long-season crops need about 90 days of runway, quick greens only 30. And with a calendar this mild, the honest answer is that planting barely stops — winter opens seasons colder regions never see.
What's on the federal record near St. Marys
Closest first, within ~10 miles of St. Marys. Listing isn't leaking, and distance isn't exposure.
- PICK-KWICK CONVENIENCE STOREUnderground Storage Tanks · 1300 ft
- WINN DIXIE STORE #70Brownfields · 1300 ft
- ST MARYS RAILROAD COUnderground Storage Tanks · 1700 ft
- HUNTLEY JIFFY STORE #352Underground Storage Tanks · 1700 ft
- TOBACCO DISCOUNTUnderground Storage Tanks · 1700 ft
- SP FOOD MART #1Underground Storage Tanks · 1700 ft
- ST MARYS MIDDLE SCHOOLUnderground Storage Tanks · 2300 ft
- JAMES L KINGUnderground Storage Tanks · 0.5 mi
- FLASH FOODS #103Underground Storage Tanks · 0.5 mi
- CAMDEN COUNTY TELEPHONE COUnderground Storage Tanks · 0.5 mi
- 33E050Nitrate · 0.6 mi
- GEORGIA PACIFIC - ST MARYS EXTRUSION OPERATIONSBrownfields · 0.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from St. Marys's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near St. Marys.
Total Sites
303
within ~10 miles of St. Marys
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of St. Marys
Severity Distribution
within ~10 miles of St. Marys
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around St. Marys, two things run higher than the national average within ~10 miles of St. Marys — PFAS (3 sites) and Nitrate (82 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in St. Marys
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the St. Marys average
Your land is one point inside St. Marys
Everything above resolves to St. Marys as a whole — one PHZM band, read across 16K acres, with hard-freeze dates borrowed from Camden County’s record because no 30-year normal resolves at this city’s own centroid. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at city scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.
Your Lot vs the St. Marys Average
St. Marys Average
- ●USDA Zones 9a, averaged across St. Marys
- ●One soil character for all of St. Marys
- ●Frost dates read at St. Marys's scale: Feb 15 to Dec 15
YOUR Parcel
- ✓Your exact zone, not St. Marys's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in St. Marys
Pull a site-specific report for your exact address in St. Marys, Georgia — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that St. Marys averages can't show:
We read public map data around St. Marys — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the St. Marys average
How we know this about St. Marys
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Camden County’s record, because none resolves here; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at city grain anywhere on this page — there is no city-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about St. Marys
When does frost risk typically end in St. Marys?
The last hard freeze (28°F) in St. Marys typically lands around Feb 15, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about Mar 8.
When is the first frost in St. Marys?
The first hard freeze (28°F) in St. Marys typically arrives around Dec 15, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Dec 1, so the watching starts about Nov 15 — about 303 days after the spring freeze cleared.
How long is the growing season in St. Marys?
Measured between 28°F hard freezes, St. Marys sees about 303 frost-free days — roughly Feb 15 through Dec 15, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 8 to Dec 1, about 268 days.
Is the soil safe to grow vegetables in St. Marys?
The federal record around St. Marys is a meaningful one — 303 documented sites, mostly Underground Storage Tanks entries (148), the nearest Underground Storage Tanks record about 0.2 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
How do I protect my plants from frost in St. Marys?
From about Nov 15 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Dec 15 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Dec 15. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at St. Marys's scale — its 9a band and its 303-day season. Your yard writes its own version of St. Marys's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at St. Marys’s own scale
5 of the readings below were taken at St. Marys's own scale — the 16,335 acres it covers and 303 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- St. Marys's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 303 documented contamination sites on the federal record near St. Marys, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- St. Marys's boundary and the 16,335 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9a and a ~303-day seasonGrowable Ground crop-matching engine
- The ecoregion at St. Marys's own centroid, the Southern Coastal PlainUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — St. Marys has no normal of its own, so its county's is the closest measured readfrom Camden County
- Soil character — no town-scale survey exists, so St. Marys's 16,335 acres read through its county's SSURGO summaryfrom Camden County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Camden County
- The growing challenges every Georgia grower plans around — written at state scale, so they stay on the state guidefrom Georgia
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Camden County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among St. Marys's 16,335 acreswhy one lot differs from the next →
- Which side of St. Marys you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 16,335 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.2 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any St. Marys-wide figureread your own land →
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