Hamilton County, in Tennessee, sits in USDA hardiness zone 8a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Well-matched crops include cabbage, fig, california poppy, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Hamilton County lies within Appalachia — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Hamilton County holds more than one microclimate.
Soils and elevations shift across Hamilton 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 Hamilton County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Hamilton County — the short answer
Hamilton County, Tennessee: USDA zone 8a, about 251 days between hard freezes, across 347K acres.
- USDA zone
- 8a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 13
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 19
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~251
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 347K 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 8a is Hamilton County's average, not your lot's — a low corner or a tree line moves it. Against Hamilton County's 251-day season, see what your own ground reads.
Heat and winter chill in Hamilton County
Across a year, Hamilton County accumulates about 4,463 growing degree days above 50°F, about 350 more than the middle Tennessee county — ahead of 83 of Tennessee’s 95 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.
Winter banks about 1,802 hours below 45°F, 257 fewer than the Tennessee middle of 2,059. Chill is what tells a fruit tree its dormancy is over, and it is set by climate rather than by anything you can build.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Hamilton County
Across Hamilton County, the ground is predominantly Ultisols, where Fullerton, Bodine, and Lily are the most extensive named soil series. The soil is generally well drained with a gravelly silt loam surface. Topsoil pH runs about 4.6–5.5, very strongly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Ultisols
Drainage
Well drained
Prime farmland
18%
Hydric soils
0%
Soil still varies lot by lot — soil types explained.
How the ground varies across Hamilton County
The USDA soil survey maps 55% of Hamilton County as well drained — but another 25% drains differently: 15% somewhat excessively drained, 9% moderately well drained.
Fullerton is the most extensive named soil at 20% of mapped acres, then Bodine (12%) and Lily (7%).
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 Hamilton County
Each reading below is measured for Hamilton 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 Hamilton County are well drained, in hydrologic group B — 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 Hamilton County runs about pH 4.6–5.5, 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
Season length
MeasuredHamilton County runs about 251 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
Winter hardiness
MeasuredHamilton County sits in USDA hardiness zone 8a.
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 Hamilton County is in
Hamilton County spans 2 EPA Level III ecoregions — Ridge and Valley (77%) and Southwestern Appalachians (23%). 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 Hamilton County
We scored all 1,086 plants against Hamilton County's own USDA zone 8a and its own 251-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 Tennessee profile.
Is it too late to plant in Hamilton County?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Feb 13; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 13 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 19 — 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 Hamilton County
Survey cells within 31 miles of Hamilton County checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 94 miles off. What to watch for.
- Japanese beetle2 documented records
- monarch butterfly20 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Hamilton County
USGS estimates 1,585 lb of Glyphosate on Hamilton County farmland in 2019, its largest by weight, ahead of 2,4-d (1,503 lb) and Atrazine (592 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 Hamilton County — and how to grow with it.
We checked the federal record across Hamilton County — 1,594 documented sites across 6 of the 9 source types we track.
The most significant on record: 32 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Hamilton 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 Hamilton County
Closest first, across Hamilton County. Listing isn't leaking, and distance isn't exposure.
- Sunrise Market No. 2Underground Storage Tanks · 1800 ft
- RITE AID #11899Brownfields · 2100 ft
- Circle K Store no. 4703604Underground Storage Tanks · 2100 ft
- Gudel's Garage IncUnderground Storage Tanks · 0.6 mi
- Conleys Service CenterUnderground Storage Tanks · 0.7 mi
- Spur MarketUnderground Storage Tanks · 0.7 mi
- Creeks Bend Golf Club, Inc.Underground Storage Tanks · 0.7 mi
- PUBLIX SUPER MARKETS #1166Brownfields · 0.9 mi
- Circle K Store No. 4703611Underground Storage Tanks · 1.0 mi
- Hixson Dispatch CenterUnderground Storage Tanks · 1.0 mi
- Golden Gallon #172Underground Storage Tanks · 1.0 mi
- Former Majik MarketUnderground Storage Tanks · 1.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Hamilton 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 Hamilton County.
Sources Checked
across Hamilton County
Severity Distribution
across Hamilton County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Hamilton County, two things run higher than the national average across Hamilton County — Superfund (32 sites) and Toxics Release Inventory (148 sites). That's not a problem with your land — it's information about it.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Hamilton 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 Hamilton County average
Your land is one point inside Hamilton County
Everything above resolves to Hamilton County as a whole — one PHZM band and one county frost record, read across 347K 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 Hamilton County Average
Hamilton County Average
- ●USDA Zones 8a, averaged across Hamilton County
- ●One soil character for all of Hamilton County
- ●Frost dates read at Hamilton County's scale: Mar 13 to Nov 19
YOUR Parcel
- ✓Your exact zone, not Hamilton County's 8a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Hamilton County
Pull a site-specific report for your exact address in Hamilton County, Tennessee — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Hamilton County averages can't show:
We read public map data around Hamilton County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Hamilton County average
How we know this about Hamilton 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 Hamilton County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Hamilton County
When does frost risk typically end in Hamilton County?
The last hard freeze (28°F) in Hamilton County typically lands around Mar 13, 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 Apr 3.
How long is the growing season in Hamilton County?
Measured between 28°F hard freezes, Hamilton County sees about 251 frost-free days — roughly Mar 13 through Nov 19, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 3 to Nov 5, about 216 days.
Is the soil safe to grow vegetables in Hamilton County?
The federal record around Hamilton County runs heavier than most — 1,594 documented sites, mostly Underground Storage Tanks entries (1,064), the nearest Underground Storage Tanks record about 0.3 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 Hamilton County's scale — its 8a band and its 251-day season. Your yard writes its own version of Hamilton 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 Tennessee's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Hamilton County’s own scale
9 of the readings below were taken at Hamilton County's own scale — its own ~251-day span between 28°F freezes, the 3 most extensive soil series mapped here and 1,594 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Hamilton County's own USDA hardiness band, zones 8aUSDA PHZM 2023
- Hamilton County's own 28°F hard-freeze dates and its ~251-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Hamilton CountyUSDA NRCS SSURGO
- 1,594 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 0.3 miles outFederal environmental registers
- Hamilton County's boundary and the 346,985 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8a and a ~251-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Hamilton County spans, Ridge and Valley the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Hamilton County for 2 tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Hamilton County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Tennessee grower plans around — written at state scale, so they stay on the state guidefrom Tennessee
What this page can’t tell you
- How the season shifts across Hamilton County — the ~251 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 Hamilton County's 346,985 acreswhy one lot differs from the next →
- Which of those 1,594 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 Hamilton Countyread your own land →