South Wilton, Connecticut, sits in USDA hardiness zone 7a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Crops well matched to these conditions include cabbage, hazelnut, california poppy, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in South Wilton, 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 South Wilton 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 South Wilton — soil, climate, flood, and parcel records. How we handle your address.
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South Wilton — the short answer
South Wilton, Connecticut: USDA zone 7a, about 225 days between hard freezes, across 717 acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 31
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 11
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~225
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 717 acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 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 7a is South Wilton's average, not your lot's — a low corner or a tree line moves it. Against South Wilton's 225-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in South Wilton
Each reading below is measured for South Wilton itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredSouth Wilton runs about 225 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
MeasuredSouth Wilton sits in USDA hardiness zone 7a.
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 South Wilton is in
South Wilton sits in the Northeastern Coastal Zone — EPA Level III, inside the wider Eastern Temperate Forests. That is read at South Wilton's own centroid rather than borrowed from Western Connecticut Planning Region.
What Grows in South Wilton
Every plant below cleared South Wilton's own zone 7a and its 225-day season. Each card opens that plant's Connecticut profile. How we score.
Is it too late to plant in South Wilton?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 3; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 31 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 11 — 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 South Wilton
Spotted lanternfly documented 0 miles from South Wilton, first recorded 2021. What to watch for.
What's on the federal record near South Wilton
Closest first, within ~10 miles of South Wilton. Listing isn't leaking, and distance isn't exposure.
- ASML US INCORPORATEDToxics Release Inventory · 200 ft
- ASML US INCORPORATEDBrownfields · 200 ft
- KENNETH LYNCH & SONS INCToxics Release Inventory · 300 ft
- ASML US, LLCUnderground Storage Tanks · 650 ft
- DIV FIFTY, LLCToxics Release Inventory · 1200 ft
- Wilton MB Service IncUnderground Storage Tanks · 2100 ft
- PERKIN ELMER CORPORATIONSuperfund · 2100 ft
- PERKIN-ELMERUnderground Storage Tanks · 2400 ft
- CT-WN 49Nitrate · 0.6 mi
- CLEAN HARBORSBrownfields · 0.6 mi
- CLEAN HARBORS - HOUSEHOLD HAZARDOUS WASTE COLLECTION EVENTBrownfields · 0.6 mi
- JAYNE BROTHERSUnderground Storage Tanks · 0.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from South Wilton'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 South Wilton.
Total Sites
1,265
within ~10 miles of South Wilton
Risk Level
Elevated
Highest-severity
16 Superfund sites
Sources Checked
within ~10 miles of South Wilton
Severity Distribution
within ~10 miles of South Wilton
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around South Wilton, Superfund runs higher than the national average — 16 sites within ~10 miles of South Wilton. 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.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in South Wilton
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 South Wilton average
Your land is one point inside South Wilton
Everything above resolves to South Wilton as a whole — one PHZM band and one 28°F frost record, read across 717 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 town 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 South Wilton Average
South Wilton Average
- ●USDA Zones 7a, averaged across South Wilton
- ●One soil character for all of South Wilton
- ●Frost dates read at South Wilton's scale: Mar 31 to Nov 11
YOUR Parcel
- ✓Your exact zone, not South Wilton's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in South Wilton
Pull a site-specific report for your exact address in South Wilton, Connecticut — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that South Wilton averages can't show:
We read public map data around South Wilton — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the South Wilton average
How we know this about South Wilton
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at South Wilton’s own record; 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 town grain anywhere on this page — there is no town-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 South Wilton
When does frost risk typically end in South Wilton?
The last hard freeze (28°F) in South Wilton typically lands around Mar 31, 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 21.
When is the first frost in South Wilton?
The first hard freeze (28°F) in South Wilton typically arrives around Nov 11, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 28, so the watching starts about Oct 12 — about 225 days after the spring freeze cleared.
How long is the growing season in South Wilton?
Measured between 28°F hard freezes, South Wilton sees about 225 frost-free days — roughly Mar 31 through Nov 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 21 to Oct 28, about 190 days.
Is the soil safe to grow vegetables in South Wilton?
The federal record around South Wilton is a meaningful one — 1,265 documented sites, mostly Underground Storage Tanks entries (602), the nearest Toxics Release Inventory record under a tenth of a mile 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 South Wilton?
From about Oct 12 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 Nov 11 (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 Nov 11. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at South Wilton's scale — its 7a band and its 225-day season. Your yard writes its own version of South Wilton'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 South Wilton’s own scale
7 of the readings below were taken at South Wilton's own scale — its own ~225-day season between 28°F freezes, the 717 acres it covers and 1,265 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- South Wilton's own USDA hardiness band, zones 7aUSDA PHZM 2023
- South Wilton's own 28°F hard-freeze dates, about Mar 31 and Nov 11 and the ~225-day span between themNOAA 1991–2020 Climate Normals
- 1,265 documented contamination sites on the federal record near South Wilton, the closest Toxics Release Inventory record under a tenth of a mile out from the town centreFederal environmental registers
- South Wilton's boundary and the 717 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~225-day seasonGrowable Ground crop-matching engine
- The ecoregion at South Wilton's own centroid, the Northeastern Coastal ZoneUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of South Wiltonlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so South Wilton's 717 acres read through its county's SSURGO summaryfrom Western Connecticut County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Western Connecticut County
- The growing challenges every Connecticut grower plans around — written at state scale, so they stay on the state guidefrom Connecticut
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Western Connecticut County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among South Wilton's 717 acreswhy one lot differs from the next →
- Which side of South Wilton you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 717 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Toxics Release Inventory record under a tenth of a mile 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 South Wilton-wide figureread your own land →
More in Connecticut
Wider growing context
What grows across ConnecticutSouth Wilton sits outside our named growing regions, so Connecticut as a whole is its closest context here.
Nearby growing guides