Thornwood, New York, sits in USDA hardiness zone 7a — 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, hazelnut, 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.
Even in Thornwood, 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 Thornwood 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 Thornwood — soil, climate, flood, and parcel records. How we handle your address.
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Thornwood — the short answer
Thornwood, New York: USDA zone 7a, about 232 days between hard freezes, across 715 acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~232
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 715 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 Thornwood's average, not your lot's — a low corner or a tree line moves it. Against Thornwood's 232-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Thornwood
Each reading below is measured for Thornwood itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredThornwood runs about 232 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
MeasuredThornwood 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 Thornwood is in
Thornwood sits in the Northeastern Coastal Zone — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Thornwood's own centroid rather than borrowed from Westchester County.
What Grows in Thornwood
Every plant below cleared Thornwood's own zone 7a and its 232-day season. Each card opens that plant's New York profile. How we score.
Is it too late to plant in Thornwood?
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 2; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 30 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 17 — 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 Thornwood
Spotted lanternfly documented 3 miles from Thornwood, first recorded 2020. What to watch for.
What's on the federal record near Thornwood
Closest first, within ~10 miles of Thornwood. Listing isn't leaking, and distance isn't exposure.
- C & Y CLEANERSBrownfields · 1400 ft
- TECHNIQUE CLEANERSBrownfields · 2000 ft
- MT PLEASANT CSD WESTLAKE HIGHBrownfields · 2400 ft
- A & A TRANSBrownfields · 2400 ft
- MT PLEASANT TOWN OF HWY DEPTBrownfields · 2400 ft
- A & G AUTO BODYBrownfields · 2400 ft
- CLEANING BY FREDERICKSBrownfields · 0.5 mi
- CVS PHARMACY #2047Brownfields · 0.5 mi
- ACME #2416Brownfields · 0.5 mi
- SUNNY CLEANERSBrownfields · 0.5 mi
- WE 567Nitrate · 0.6 mi
- CVS PHARMACY #0807Brownfields · 0.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Thornwood'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 Thornwood.
Total Sites
966
within ~10 miles of Thornwood
Risk Level
Elevated
Highest-severity
10 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Thornwood
Severity Distribution
within ~10 miles of Thornwood
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Thornwood, two things run higher than the national average within ~10 miles of Thornwood — PFAS (18 sites) and Brownfields (695 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.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in Thornwood
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 Thornwood average
Your land is one point inside Thornwood
Everything above resolves to Thornwood as a whole — one PHZM band and one 28°F frost record, read across 715 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 Thornwood Average
Thornwood Average
- ●USDA Zones 7a, averaged across Thornwood
- ●One soil character for all of Thornwood
- ●Frost dates read at Thornwood's scale: Mar 30 to Nov 17
YOUR Parcel
- ✓Your exact zone, not Thornwood's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Thornwood
Pull a site-specific report for your exact address in Thornwood, New York — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Thornwood averages can't show:
We read public map data around Thornwood — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Thornwood average
How we know this about Thornwood
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 Thornwood’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 Thornwood
When does frost risk typically end in Thornwood?
The last hard freeze (28°F) in Thornwood typically lands around Mar 30, 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 20.
When is the first frost in Thornwood?
The first hard freeze (28°F) in Thornwood typically arrives around Nov 17, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 3, so the watching starts about Oct 18 — about 232 days after the spring freeze cleared.
How long is the growing season in Thornwood?
Measured between 28°F hard freezes, Thornwood sees about 232 frost-free days — roughly Mar 30 through Nov 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 20 to Nov 3, about 197 days.
Is the soil safe to grow vegetables in Thornwood?
The federal record around Thornwood is a meaningful one — 966 documented sites, mostly Brownfields entries (695), the nearest Brownfields record about 0.3 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 Thornwood?
From about Oct 18 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 17 (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 17. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Thornwood's scale — its 7a band and its 232-day season. Your yard writes its own version of Thornwood'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 Thornwood’s own scale
7 of the readings below were taken at Thornwood's own scale — its own ~232-day season between 28°F freezes, the 715 acres it covers and 966 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Thornwood's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Thornwood's own 28°F hard-freeze dates, about Mar 30 and Nov 17 and the ~232-day span between themNOAA 1991–2020 Climate Normals
- 966 documented contamination sites on the federal record near Thornwood, the closest Brownfields record about 0.3 miles out from the town centreFederal environmental registers
- Thornwood's boundary and the 715 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~232-day seasonGrowable Ground crop-matching engine
- The ecoregion at Thornwood's own centroid, the Northeastern Coastal ZoneUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Thornwoodlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Thornwood's 715 acres read through its county's SSURGO summaryfrom Westchester County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Westchester County
- The growing challenges every New York grower plans around — written at state scale, so they stay on the state guidefrom New York
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Westchester County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Thornwood's 715 acreswhy one lot differs from the next →
- Which side of Thornwood you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 715 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.3 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 Thornwood-wide figureread your own land →
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