Oswego County, in New York, sits in USDA hardiness zone 5b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Reliable performers under these conditions include cabbage, cranberry, lavender, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Oswego County holds more than one microclimate.
Soils and elevations shift across Oswego County, so your frost dates and drainage aren't the county average. 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 Oswego County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Oswego County — the short answer
Oswego County, New York: USDA zone 5b, about 200 days between hard freezes, across 609K acres.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 17
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 3
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~200
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 609K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 5b is Oswego County's average, not your lot's — a low corner or a tree line moves it. Against Oswego County's 200-day season, see what your own ground reads.
Heat in Oswego County
Across a year, Oswego County accumulates about 2,301 growing degree days above 50°F, about 65 more than the middle New York county — ahead of 34 of New York’s 62 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Oswego County
Across Oswego County, the ground is predominantly Inceptisols, where Worth, Empeyville, and Ira are the most extensive named soil series. The soil is generally well drained with a very fine sandy loam surface. Topsoil pH runs about 4.6–5.9, strongly acidic. Rainfall drains through hydrologic group D soils.
Soil order
Inceptisols
Drainage
Well drained
Prime farmland
10%
Hydric soils
20%
Soil still varies lot by lot — soil types explained.
How the ground varies across Oswego County
The USDA soil survey maps 25% of Oswego County as well drained — but another 68% drains differently: 16% moderately well drained, 15% somewhat poorly drained.
Worth is the most extensive named soil at 14% of mapped acres, then Empeyville (10%) and Ira (9%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Oswego County
Each reading below is measured for Oswego County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Oswego County are well drained, in hydrologic group D — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Oswego County runs about pH 4.6–5.9, on the acidic side.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Wet ground
MeasuredAbout 20% of Oswego County is mapped as hydric — wetland — soil.
If your lot falls in one of those pockets, a standard in-ground bed will fight waterlogging all season, and roots that need air will struggle.
Check how your own ground drains before you dig; raised beds or moisture-loving plantings turn a wet corner from a problem into a niche.
USDA NRCS SSURGO
Season length
MeasuredOswego County runs about 200 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
The kind of country Oswego County is in
Oswego County spans 2 EPA Level III ecoregions — Eastern Great Lakes Lowlands (78%) and Northeastern Highlands (22%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Oswego County
We scored all 1,086 plants against Oswego County's own USDA zone 5b and its own 200-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's New York profile.
Is it too late to plant in Oswego County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 20; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 17 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 3 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
Documented around Oswego County
Spotted lanternfly documented 28 miles from Oswego County, first recorded 2022. What to watch for.
- Japanese beetle2 documented records
- monarch butterfly139 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Oswego County
USGS estimates 13,808 lb of Metolachlor & Metolachlor-s on Oswego County farmland in 2019, its largest by weight, ahead of Metolachlor-s (10,690 lb) and Glyphosate (8,796 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Oswego County — and how to grow with it.
We checked the federal record across Oswego County — 601 documented sites across 7 of the 9 source types we track.
The most significant on record: 10 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Oswego County carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Oswego County
Closest first, across Oswego County. Listing isn't leaking, and distance isn't exposure.
- KWIK-FILL #M0057-004Underground Storage Tanks · 1.0 mi
- LEO J. KESSELRING PROPERTYUnderground Storage Tanks · 1.1 mi
- KWIK FILL MO400 / 400Underground Storage Tanks · 1.1 mi
- FORMER WATSON GAS STATIONUnderground Storage Tanks · 1.2 mi
- KINNEY DRUGS STORE #47Brownfields · 1.2 mi
- NYSDOTUnderground Storage Tanks · 1.3 mi
- GRANDMA BROWNS BEANS, INC.Underground Storage Tanks · 1.3 mi
- AGWAY ENERGY PRODUCTSUnderground Storage Tanks · 1.3 mi
- FASTRAC MARKET #219Underground Storage Tanks · 1.4 mi
- FASTRAC 219Brownfields · 1.4 mi
- SCENIC AVE. GAS INC.Underground Storage Tanks · 1.5 mi
- DOLLAR GENERAL STORE #6437Brownfields · 1.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Oswego County'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 Oswego County.
Severity Distribution
across Oswego County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Oswego County, Superfund runs higher than the national average — 10 sites across Oswego County. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Oswego County
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 Oswego County average
Your land is one point inside Oswego County
Everything above resolves to Oswego County as a whole — one PHZM band and one county frost record, read across 609K acres. 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 county 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 county average.
Your Lot vs the Oswego County Average
Oswego County Average
- ●USDA Zones 5b, averaged across Oswego County
- ●One soil character for all of Oswego County
- ●Frost dates read at Oswego County's scale: Apr 17 to Nov 3
YOUR Parcel
- ✓Your exact zone, not Oswego County's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Oswego County
Pull a site-specific report for your exact address in Oswego County, New York — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Oswego County averages can't show:
We read public map data around Oswego County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Oswego County average
How we know this about Oswego County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Oswego County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Oswego County
When does frost risk typically end in Oswego County?
The last hard freeze (28°F) in Oswego County typically lands around Apr 17, 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 May 8.
How long is the growing season in Oswego County?
Measured between 28°F hard freezes, Oswego County sees about 200 frost-free days — roughly Apr 17 through Nov 3, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 8 to Oct 20, about 165 days.
Is the soil safe to grow vegetables in Oswego County?
The federal record around Oswego County runs heavier than most — 601 documented sites, mostly Underground Storage Tanks entries (327), the nearest Underground Storage Tanks record about 1.0 miles out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
Everything above is measured at Oswego County's scale — its 5b band and its 200-day season. Your yard writes its own version of Oswego County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads New York's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Oswego County’s own scale
9 of the readings below were taken at Oswego County's own scale — its own ~200-day span between 28°F freezes, the 3 most extensive soil series mapped here and 601 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Oswego County's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Oswego County's own 28°F hard-freeze dates and its ~200-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Oswego CountyUSDA NRCS SSURGO
- 601 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 1.0 miles outFederal environmental registers
- Oswego County's boundary and the 609,037 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~200-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Oswego County spans, Eastern Great Lakes Lowlands the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Oswego County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Oswego County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every New York grower plans around — written at state scale, so they stay on the state guidefrom New York
What this page can’t tell you
- How the season shifts across Oswego County — the ~200 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Oswego County's 609,037 acreswhy one lot differs from the next →
- Which of those 601 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Oswego Countyread your own land →