Charlestown, Rhode Island, 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.
Reliable performers under these conditions include cabbage, hazelnut, california poppy, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Charlestown, 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 Charlestown 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 Charlestown — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Charlestown — the short answer
Charlestown, Rhode Island: USDA zone 7a, about 235 days between hard freezes, across 1K acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 19
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~235
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 Charlestown's average, not your lot's — a low corner or a tree line moves it. Against Charlestown's 235-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Charlestown
Each reading below is measured for Charlestown itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCharlestown runs about 235 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
MeasuredCharlestown 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 Charlestown is in
Charlestown sits in the Northeastern Coastal Zone — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Charlestown's own centroid rather than borrowed from Washington County.
What Grows in Charlestown
Every plant below cleared Charlestown's own zone 7a and its 235-day season. Each card opens that plant's Rhode Island profile. How we score.
Is it too late to plant in Charlestown?
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 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 29 (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 Charlestown
Spotted lanternfly documented 18 miles from Charlestown, first recorded 2021. What to watch for.
What's on the federal record near Charlestown
Closest first, within ~10 miles of Charlestown. Listing isn't leaking, and distance isn't exposure.
- MW-20TNitrate · 1000 ft
- MW-171CNitrate · 1600 ft
- CUMBERLAND FARMS, INC. #3848Underground Storage Tanks · 2400 ft
- MW-283RINitrate · 2500 ft
- MW-24SDNitrate · 0.5 mi
- GREGORY'S AUTOMOTIVE, INC.Underground Storage Tanks · 0.6 mi
- MW-54SDNitrate · 0.6 mi
- PATS POWER EQUIPMENT INCBrownfields · 0.7 mi
- C V S #10299Brownfields · 0.7 mi
- MW-30EBNitrate · 0.7 mi
- U.S. ARMY CORPS ENGINEERSUnderground Storage Tanks · 0.7 mi
- BURLINGAME STATE PARKUnderground Storage Tanks · 0.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Charlestown'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 Charlestown.
Sources Checked
within ~10 miles of Charlestown
Severity Distribution
within ~10 miles of Charlestown
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Charlestown, two things run higher than the national average within ~10 miles of Charlestown — Nitrate (264 sites) and Superfund (12 sites). That's not a problem with your land — it's information about it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Charlestown
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 Charlestown average
Your land is one point inside Charlestown
Everything above resolves to Charlestown as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Charlestown Average
Charlestown Average
- ●USDA Zones 7a, averaged across Charlestown
- ●One soil character for all of Charlestown
- ●Frost dates read at Charlestown's scale: Mar 29 to Nov 19
YOUR Parcel
- ✓Your exact zone, not Charlestown's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Charlestown
Pull a site-specific report for your exact address in Charlestown, Rhode Island — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Charlestown averages can't show:
We read public map data around Charlestown — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Charlestown average
How we know this about Charlestown
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 Charlestown’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 Charlestown
When does frost risk typically end in Charlestown?
The last hard freeze (28°F) in Charlestown typically lands around Mar 29, 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 19.
When is the first frost in Charlestown?
The first hard freeze (28°F) in Charlestown typically arrives around Nov 19, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 5, so the watching starts about Oct 20 — about 235 days after the spring freeze cleared.
How long is the growing season in Charlestown?
Measured between 28°F hard freezes, Charlestown sees about 235 frost-free days — roughly Mar 29 through Nov 19, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 19 to Nov 5, about 200 days.
Is the soil safe to grow vegetables in Charlestown?
The federal record around Charlestown is a meaningful one — 656 documented sites, mostly Nitrate entries (264), the nearest Nitrate record about 0.2 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 Charlestown?
From about Oct 20 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 19 (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 19. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Charlestown's scale — its 7a band and its 235-day season. Your yard writes its own version of Charlestown'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 Charlestown’s own scale
7 of the readings below were taken at Charlestown's own scale — its own ~235-day season between 28°F freezes, the 1,448 acres it covers and 656 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Charlestown's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Charlestown's own 28°F hard-freeze dates, about Mar 29 and Nov 19 and the ~235-day span between themNOAA 1991–2020 Climate Normals
- 656 documented contamination sites on the federal record near Charlestown, the closest Nitrate record about 0.2 miles out from the town centreFederal environmental registers
- Charlestown's boundary and the 1,448 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~235-day seasonGrowable Ground crop-matching engine
- The ecoregion at Charlestown's own centroid, the Northeastern Coastal ZoneUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Charlestownlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Charlestown's 1,448 acres read through its county's SSURGO summaryfrom Washington County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Washington County
- The growing challenges every Rhode Island grower plans around — written at state scale, so they stay on the state guidefrom Rhode Island
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Washington County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Charlestown's 1,448 acreswhy one lot differs from the next →
- Which side of Charlestown you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,448 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.2 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 Charlestown-wide figureread your own land →