Rockville, Minnesota, sits in USDA hardiness zone 4b — a zone band wide enough that plant choice, not possibility, is the interesting question.
These conditions suit cabbage, cranberry, turkish rocket, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Rockville, 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 Rockville 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 Rockville — soil, climate, flood, and parcel records. How we handle your address.
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Rockville — the short answer
Rockville, Minnesota: USDA zone 4b, about 178 days between hard freezes, across 18K acres of city.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 22
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~178
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 18K 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 Rockville's average, not your lot's — a low corner or a tree line moves it. Against Rockville's 178-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Rockville
Each reading below is measured for Rockville itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredRockville runs about 178 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
MeasuredRockville 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 Rockville is in
Rockville sits in the North Central Hardwood Forests — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Rockville's own centroid rather than borrowed from Stearns County.
What Grows in Rockville
Every plant below cleared Rockville's own zone 4b and its 178-day season. Each card opens that plant's Minnesota profile. How we score.
Is it too late to plant in Rockville?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 25; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 22 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 17 — 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 Rockville
Closest first, within ~10 miles of Rockville. Listing isn't leaking, and distance isn't exposure.
- PICKUPS N POWERSPORTS, INC.Brownfields · 1600 ft
- 461828Nitrate · 0.7 mi
- OAK HILL CUSTOM CABINETS INCBrownfields · 0.7 mi
- COLD SPRING GRANITE - ROCKVILBrownfields · 0.9 mi
- MASELTER CABINETS INCBrownfields · 1.1 mi
- Granite Edge CafeUnderground Storage Tanks · 1.1 mi
- SCHAEFERS AUTO ELECTRIC INCBrownfields · 1.3 mi
- 497679Nitrate · 1.6 mi
- K AND C FOREIGN AUTO PARTS LLCBrownfields · 1.8 mi
- STICKNEY HILL DAIRYBrownfields · 1.8 mi
- JLAM INCBrownfields · 1.9 mi
- SJ LOUIS CONSTRUCTION INCBrownfields · 1.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Rockville'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 Rockville.
Sources Checked
within ~10 miles of Rockville
Severity Distribution
within ~10 miles of Rockville
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Rockville, Nitrate runs higher than the national average — 310 sites within ~10 miles of Rockville. 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 Rockville
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 Rockville average
Your land is one point inside Rockville
Everything above resolves to Rockville as a whole — one PHZM band and one 28°F frost record, read across 18K 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 Rockville Average
Rockville Average
- ●USDA Zones 4b, averaged across Rockville
- ●One soil character for all of Rockville
- ●Frost dates read at Rockville's scale: Apr 22 to Oct 17
YOUR Parcel
- ✓Your exact zone, not Rockville's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Rockville
Pull a site-specific report for your exact address in Rockville, Minnesota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Rockville averages can't show:
We read public map data around Rockville — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Rockville average
How we know this about Rockville
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 Rockville’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 Rockville
When does frost risk typically end in Rockville?
The last hard freeze (28°F) in Rockville typically lands around Apr 22, 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 13.
When is the first frost in Rockville?
The first hard freeze (28°F) in Rockville typically arrives around Oct 17, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 3, so the watching starts about Sep 17 — about 178 days after the spring freeze cleared.
How long is the growing season in Rockville?
Measured between 28°F hard freezes, Rockville sees about 178 frost-free days — roughly Apr 22 through Oct 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 13 to Oct 3, about 143 days.
Is the soil safe to grow vegetables in Rockville?
The federal record around Rockville is a meaningful one — 954 documented sites, mostly Brownfields entries (416), 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 Rockville?
From about Sep 17 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 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 Oct 17. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Rockville's scale — its 4b band and its 178-day season. Your yard writes its own version of Rockville'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 Rockville’s own scale
6 of the readings below were taken at Rockville's own scale — its own ~178-day season between 28°F freezes, the 18,356 acres it covers and 954 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Rockville's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Rockville's own 28°F hard-freeze dates, about Apr 22 and Oct 17 and the ~178-day span between themNOAA 1991–2020 Climate Normals
- 954 documented contamination sites on the federal record near Rockville, the closest Brownfields record about 0.3 miles out from the town centreFederal environmental registers
- Rockville's boundary and the 18,356 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~178-day seasonGrowable Ground crop-matching engine
- The ecoregion at Rockville'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 Rockville's 18,356 acres read through its county's SSURGO summaryfrom Stearns County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Stearns 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 Stearns County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Rockville's 18,356 acreswhy one lot differs from the next →
- Which side of Rockville you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 18,356 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 Rockville-wide figureread your own land →
More in Minnesota
Wider growing context
What grows across MinnesotaRockville sits outside our named growing regions, so Minnesota as a whole is its closest context here.
Nearby growing guides