Watertown, Minnesota, sits in USDA hardiness zone 4b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
The conditions favor cabbage, cranberry, turkish rocket, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Watertown, 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 Watertown 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 Watertown — soil, climate, flood, and parcel records. How we handle your address.
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Watertown — the short answer
Watertown, Minnesota: USDA zone 4b, about 186 days between hard freezes, across 2K acres of city.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 18
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 21
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~186
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 2K 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 4b is Watertown's average, not your lot's — a low corner or a tree line moves it. Against Watertown's 186-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Watertown
Each reading below is measured for Watertown itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredWatertown runs about 186 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
MeasuredWatertown sits in USDA hardiness zone 4b.
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 Watertown is in
Watertown sits in the North Central Hardwood Forests — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Watertown's own centroid rather than borrowed from Carver County.
What Grows in Watertown
Every plant below cleared Watertown's own zone 4b and its 186-day season. Each card opens that plant's Minnesota profile. How we score.
Is it too late to plant in Watertown?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Mar 21; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 18 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 21 — 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.
What's on the federal record near Watertown
Closest first, within ~10 miles of Watertown. Listing isn't leaking, and distance isn't exposure.
- RISTOW REPAIRBrownfields · 600 ft
- Ristow RepairUnderground Storage Tanks · 600 ft
- R & D PERFORMANCEBrownfields · 700 ft
- ARVU AUTOBrownfields · 700 ft
- CARVER COUNTY MAINT SHOP WATERTOWN 3Brownfields · 750 ft
- DERSON MANUFACTURING INCBrownfields · 1100 ft
- HECKSEL MACHINE INCBrownfields · 1200 ft
- Carver County Maintenance ShopUnderground Storage Tanks · 1200 ft
- Riverside 76Underground Storage Tanks · 1300 ft
- WATERTOWN DENTALBrownfields · 1400 ft
- WATERTOWN ALL AROUND PARTS INCBrownfields · 1400 ft
- WATERTOWN PHARMACY LLCBrownfields · 1400 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Watertown'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 Watertown.
Total Sites
603
within ~10 miles of Watertown
Risk Level
Elevated
Highest-severity
18 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Watertown
Severity Distribution
within ~10 miles of Watertown
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Watertown, two things run higher than the national average within ~10 miles of Watertown — Brownfields (341 sites) and PFAS (5 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Watertown
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 Watertown average
Your land is one point inside Watertown
Everything above resolves to Watertown as a whole — one PHZM band and one 28°F frost record, read across 2K 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 Watertown Average
Watertown Average
- ●USDA Zones 4b, averaged across Watertown
- ●One soil character for all of Watertown
- ●Frost dates read at Watertown's scale: Apr 18 to Oct 21
YOUR Parcel
- ✓Your exact zone, not Watertown's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Watertown
Pull a site-specific report for your exact address in Watertown, Minnesota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Watertown averages can't show:
We read public map data around Watertown — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Watertown average
How we know this about Watertown
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 Watertown’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 Watertown
When does frost risk typically end in Watertown?
The last hard freeze (28°F) in Watertown typically lands around Apr 18, 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 9.
When is the first frost in Watertown?
The first hard freeze (28°F) in Watertown typically arrives around Oct 21, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 7, so the watching starts about Sep 21 — about 186 days after the spring freeze cleared.
How long is the growing season in Watertown?
Measured between 28°F hard freezes, Watertown sees about 186 frost-free days — roughly Apr 18 through Oct 21, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 9 to Oct 7, about 151 days.
Is the soil safe to grow vegetables in Watertown?
The federal record around Watertown is a meaningful one — 603 documented sites, mostly Brownfields entries (341), the nearest Brownfields 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 Watertown?
From about Sep 21 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 21 (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 21. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Watertown's scale — its 4b band and its 186-day season. Your yard writes its own version of Watertown'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 Watertown’s own scale
6 of the readings below were taken at Watertown's own scale — its own ~186-day season between 28°F freezes, the 1,681 acres it covers and 603 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Watertown's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Watertown's own 28°F hard-freeze dates, about Apr 18 and Oct 21 and the ~186-day span between themNOAA 1991–2020 Climate Normals
- 603 documented contamination sites on the federal record near Watertown, the closest Brownfields record about 0.1 miles out from the town centreFederal environmental registers
- Watertown's boundary and the 1,681 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~186-day seasonGrowable Ground crop-matching engine
- The ecoregion at Watertown's own centroid, the North Central Hardwood ForestsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Watertown's 1,681 acres read through its county's SSURGO summaryfrom Carver County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Carver County
- The growing challenges every Minnesota grower plans around — written at state scale, so they stay on the state guidefrom Minnesota
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Carver County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Watertown's 1,681 acreswhy one lot differs from the next →
- Which side of Watertown you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,681 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Watertown-wide figureread your own land →
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