Northwest Hills Planning Region, in Connecticut, sits in USDA hardiness zone 6a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Among the crops suited to this profile: cabbage, hazelnut, lavender, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Northwest Hills Planning Region lies within the Litchfield Hills — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Northwest Hills Planning Region holds more than one microclimate.
Soils and elevations shift across Northwest Hills Planning Region, 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 Northwest Hills Planning Region — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Northwest Hills Planning Region — the short answer
Northwest Hills Planning Region, Connecticut: USDA zone 6a, about 191 days between hard freezes, across 503K acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 19
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 27
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~191
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 503K 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 6a is Northwest Hills Planning Region's average, not your lot's — a low corner or a tree line moves it. Against Northwest Hills Planning Region's 191-day season, see what your own ground reads.
Heat in Northwest Hills Planning Region
Across a year, Northwest Hills Planning Region accumulates about 2,076 growing degree days above 50°F, about 588 fewer than the middle Connecticut county — no other Connecticut county banks fewer. 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 Northwest Hills County
Detailed USDA soil-survey (SSURGO) mapping is limited across Northwest Hills County, so there isn't a reliable county-wide soil summary to show here yet — a gap in the national survey, not in the ground itself.
Soil still varies lot by lot — soil types explained.
What this means for growing in Northwest Hills Planning Region
Each reading below is measured for Northwest Hills Planning Region itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredNorthwest Hills Planning Region runs about 191 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredNorthwest Hills Planning Region sits in USDA hardiness zone 6a.
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
What Grows in Northwest Hills Planning Region
We scored all 1,086 plants against Northwest Hills Planning Region's own USDA zone 6a and its own 191-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 Connecticut profile.
Is it too late to plant in Northwest Hills Planning Region?
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 22; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 19 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 27 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
Documented around Northwest Hills Planning Region
Spotted lanternfly documented 15 miles from Northwest Hills Planning Region, first recorded 2021. What to watch for.
Safe to Grow Here?
What the federal record shows across Northwest Hills County — and how to grow with it.
We checked the federal record across Northwest Hills County — 1,007 documented sites across 8 of the 9 source types we track.
The most significant on record: 5 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Northwest Hills County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Northwest Hills Planning Region
Closest first, across Northwest Hills County. Listing isn't leaking, and distance isn't exposure.
- CT-GO 15Nitrate · 1.3 mi
- Village Markey & Gas LLCUnderground Storage Tanks · 1.4 mi
- Goshen Tractor, Inc.Underground Storage Tanks · 1.6 mi
- CT-GO 51Nitrate · 1.6 mi
- GOSHEN CO. #5304Underground Storage Tanks · 1.7 mi
- A GALLO COUnderground Storage Tanks · 1.7 mi
- GOSHEN PUBLIC WORKS DEPARTMENTUnderground Storage Tanks · 1.7 mi
- NODINES SMOKE HOUSEUnderground Storage Tanks · 1.7 mi
- WOODRIDGE LAKE SEWER DISTRICT PLANTUnderground Storage Tanks · 1.7 mi
- WILLIS OCAINUnderground Storage Tanks · 1.7 mi
- GOSHEN OIL CO INCUnderground Storage Tanks · 1.7 mi
- TORRINGTON COUNTRY CLUBUnderground Storage Tanks · 1.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Northwest Hills Planning Region'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 Northwest Hills Planning Region.
Sources Checked
across Northwest Hills County
Severity Distribution
across Northwest Hills County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Northwest Hills Planning Region, Nitrate runs higher than the national average — 292 sites across Northwest Hills County. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Northwest Hills Planning Region
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 Northwest Hills Planning Region average
Your land is one point inside Northwest Hills Planning Region
Everything above resolves to Northwest Hills Planning Region as a whole — one PHZM band and one county frost record, read across 503K 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 Northwest Hills Planning Region Average
Northwest Hills Planning Region Average
- ●USDA Zones 6a, averaged across Northwest Hills Planning Region
- ●One soil character for all of Northwest Hills Planning Region
- ●Frost dates read at Northwest Hills Planning Region's scale: Apr 19 to Oct 27
YOUR Parcel
- ✓Your exact zone, not Northwest Hills Planning Region's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Northwest Hills Planning Region
Pull a site-specific report for your exact address in Northwest Hills Planning Region, Connecticut — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Northwest Hills Planning Region averages can't show:
We read public map data around Northwest Hills Planning Region — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Northwest Hills Planning Region average
How we know this about Northwest Hills Planning Region
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 Northwest Hills Planning Region carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Northwest Hills Planning Region
When does frost risk typically end in Northwest Hills Planning Region?
The last hard freeze (28°F) in Northwest Hills Planning Region typically lands around Apr 19, 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 10.
How long is the growing season in Northwest Hills Planning Region?
Measured between 28°F hard freezes, Northwest Hills Planning Region sees about 191 frost-free days — roughly Apr 19 through Oct 27, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 10 to Oct 13, about 156 days.
Is the soil safe to grow vegetables in Northwest Hills Planning Region?
The federal record around Northwest Hills Planning Region is a meaningful one — 1,007 documented sites, mostly Underground Storage Tanks entries (483), the nearest Nitrate record about 1.3 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.
Everything above is measured at Northwest Hills Planning Region's scale — its 6a band and its 191-day season. Your yard writes its own version of Northwest Hills Planning Region'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 Connecticut's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Northwest Hills Planning Region’s own scale
5 of the readings below were taken at Northwest Hills Planning Region's own scale — its own ~191-day span between 28°F freezes and 1,007 documented sites inside its boundary; 2 are borrowed from a wider read, named and linked below.
Measured here
- Northwest Hills Planning Region's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Northwest Hills Planning Region's own 28°F hard-freeze dates and its ~191-day span between themNOAA 1991–2020 Climate Normals
- 1,007 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 1.3 miles outFederal environmental registers
- Northwest Hills Planning Region's boundary and the 503,450 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~191-day seasonGrowable Ground crop-matching engine
Inherited from a wider read
- Soil character — the national survey's mapping is too sparse here for a county summary, so the state's dominant soils are the closest readfrom Connecticut
- The growing challenges every Connecticut grower plans around — written at state scale, so they stay on the state guidefrom Connecticut
What this page can’t tell you
- How the season shifts across Northwest Hills Planning Region — the ~191 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 Northwest Hills Planning Region's 503,450 acreswhy one lot differs from the next →
- Which of those 1,007 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 Northwest Hills Planning Regionread your own land →