Danbury, Connecticut, sits in USDA hardiness zone 6b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
These conditions suit cabbage, blackberry, california poppy, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Danbury, 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 Danbury 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 Danbury — soil, climate, flood, and parcel records. How we handle your address.
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Danbury — the short answer
Danbury, Connecticut: USDA zone 6b, about 195 days between hard freezes, across 27K acres of city.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 15
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 27
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~195
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 27K 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 6b is Danbury's average, not your lot's — a low corner or a tree line moves it. Against Danbury's 195-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Danbury
Each reading below is measured for Danbury itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDanbury runs about 195 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
MeasuredDanbury sits in USDA hardiness zone 6b.
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 Danbury is in
Danbury sits in the Northeastern Coastal Zone — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Danbury's own centroid rather than borrowed from Western Connecticut Planning Region.
What Grows in Danbury
Every plant below cleared Danbury's own zone 6b and its 195-day season. Each card opens that plant's Connecticut profile. How we score.
Is it too late to plant in Danbury?
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 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 15 (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. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
Documented around Danbury
Spotted lanternfly documented 4 miles from Danbury, first recorded 2022. What to watch for.
What's on the federal record near Danbury
Closest first, within ~10 miles of Danbury. Listing isn't leaking, and distance isn't exposure.
- WEST LAKE TREATMENT PLANTUnderground Storage Tanks · 600 ft
- BUGS MOTORSUnderground Storage Tanks · 0.5 mi
- 54 WESTVILLE AVEBrownfields · 0.6 mi
- PMG #8682Underground Storage Tanks · 0.7 mi
- ABILITY BEYONDBrownfields · 0.7 mi
- 6 WESTVILLE AVEBrownfields · 0.8 mi
- LAKE AVENUE SERVICE STATIONUnderground Storage Tanks · 0.8 mi
- Smart Food of DanburyUnderground Storage Tanks · 0.8 mi
- DIVINE ENTERPRISESBrownfields · 0.8 mi
- O'NEILL ATHLETIC convacation CENTER/ Western CT State UniversityUnderground Storage Tanks · 0.8 mi
- WATSON PHARMACEUTICALSToxics Release Inventory · 0.9 mi
- SHELL FACILITY 100052Underground Storage Tanks · 0.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Danbury'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 Danbury.
Sources Checked
within ~10 miles of Danbury
Severity Distribution
within ~10 miles of Danbury
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Danbury, Superfund runs higher than the national average — 18 sites within ~10 miles of Danbury. 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 Danbury
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 Danbury average
Your land is one point inside Danbury
Everything above resolves to Danbury as a whole — one PHZM band and one 28°F frost record, read across 27K 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 city 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 Danbury Average
Danbury Average
- ●USDA Zones 6b, averaged across Danbury
- ●One soil character for all of Danbury
- ●Frost dates read at Danbury's scale: Apr 15 to Oct 27
YOUR Parcel
- ✓Your exact zone, not Danbury's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Danbury
Pull a site-specific report for your exact address in Danbury, Connecticut — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Danbury averages can't show:
We read public map data around Danbury — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Danbury average
How we know this about Danbury
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Danbury’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 city grain anywhere on this page — there is no city-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 Danbury
When does frost risk typically end in Danbury?
The last hard freeze (28°F) in Danbury typically lands around Apr 15, 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 6.
When is the first frost in Danbury?
The first hard freeze (28°F) in Danbury typically arrives around Oct 27, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 13, so the watching starts about Sep 27 — about 195 days after the spring freeze cleared.
How long is the growing season in Danbury?
Measured between 28°F hard freezes, Danbury sees about 195 frost-free days — roughly Apr 15 through Oct 27, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 6 to Oct 13, about 160 days.
Is the soil safe to grow vegetables in Danbury?
The federal record around Danbury is a meaningful one — 1,101 documented sites, mostly Underground Storage Tanks entries (490), the nearest Underground Storage Tanks record about 0.1 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 Danbury?
From about Sep 27 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 Oct 27 (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 Oct 27. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Danbury's scale — its 6b band and its 195-day season. Your yard writes its own version of Danbury'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 Danbury’s own scale
7 of the readings below were taken at Danbury's own scale — its own ~195-day season between 28°F freezes, the 26,899 acres it covers and 1,101 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Danbury's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Danbury's own 28°F hard-freeze dates, about Apr 15 and Oct 27 and the ~195-day span between themNOAA 1991–2020 Climate Normals
- 1,101 documented contamination sites on the federal record near Danbury, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Danbury's boundary and the 26,899 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~195-day seasonGrowable Ground crop-matching engine
- The ecoregion at Danbury's own centroid, the Northeastern Coastal ZoneUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Danburylydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Danbury's 26,899 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 Danbury's 26,899 acreswhy one lot differs from the next →
- Which side of Danbury you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 26,899 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 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 Danbury-wide figureread your own land →
More in Connecticut
Wider growing context
What grows across ConnecticutDanbury sits outside our named growing regions, so Connecticut as a whole is its closest context here.
Nearby growing guides