Rockville, Utah, sits in USDA hardiness zone 8a — a zone band wide enough that plant choice, not possibility, is the interesting question.
These conditions suit cabbage, fig, california poppy, 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, Utah: USDA zone 8a, about 262 days between hard freezes, across 5K acres of town.
- USDA zone
- 8a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 3
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~262
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 5K 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 8a is Rockville's average, not your lot's — a low corner or a tree line moves it. Against Rockville's 262-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 262 days between hard freezes — close to year-round growing.
Frost is rarely the limit here; winter plantings are as real as summer ones, and the harder question is which crops shrug off the summer heat.
Grow cool-season crops through the mild winter, and choose heat-tolerant varieties for the summer beds.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredRockville sits in USDA hardiness zone 8a.
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 Colorado Plateaus — EPA Level III, inside the wider North American Deserts. That is read at Rockville's own centroid, and it is not what its county reads: Washington County is mostly Mojave Basin and Range. The wider page above you is answering a different question about different ground.
What Grows in Rockville
Every plant below cleared Rockville's own zone 8a and its 262-day season. Each card opens that plant's Utah 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 Feb 3; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 3 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 20 — long-season crops need about 90 days of runway, quick greens only 30. And with a calendar this mild, the honest answer is that planting barely stops — winter opens seasons colder regions never see.
What's on the federal record near Rockville
Closest first, within ~10 miles of Rockville. Listing isn't leaking, and distance isn't exposure.
- (C-42-10) 7bdd- 1Nitrate · 1.6 mi
- JUNCTION MARKET XUnderground Storage Tanks · 3.4 mi
- ZION CANYON EXXONUnderground Storage Tanks · 3.9 mi
- ZION CANYON SHELLUnderground Storage Tanks · 4.1 mi
- Caliente #5Mining · 4.5 mi
- SPRINGDALE TEXACOUnderground Storage Tanks · 4.7 mi
- ZION NATIONAL PARKBrownfields · 5.2 mi
- ZION NATIONAL PARKToxics Release Inventory · 5.2 mi
- LITTLE CREEK STATIONUnderground Storage Tanks · 5.2 mi
- ZION CANYON WATER SYSTEMPFAS · 5.3 mi
- ZION NATIONAL PARKUnderground Storage Tanks · 5.7 mi
- U.S.WEST 671669 LITTLE CREEK RADIOUnderground Storage Tanks · 8.1 mi
2 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.
Total Sites
15
within ~10 miles of Rockville
Risk Level
Low
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Rockville
Severity Distribution
within ~10 miles of Rockville
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •Mine waste leaches heavy metals. Test for lead, arsenic and cadmium before growing food here.
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 5K 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 Rockville Average
Rockville Average
- ●USDA Zones 8a, averaged across Rockville
- ●One soil character for all of Rockville
- ●Frost dates read at Rockville's scale: Mar 3 to Nov 20
YOUR Parcel
- ✓Your exact zone, not Rockville's 8a
- ✓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, Utah — 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 town’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 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 Rockville
When does frost risk typically end in Rockville?
The last hard freeze (28°F) in Rockville typically lands around Mar 3, 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 Mar 24.
When is the first frost in Rockville?
The first hard freeze (28°F) in Rockville typically arrives around Nov 20, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 6, so the watching starts about Oct 21 — about 262 days after the spring freeze cleared.
How long is the growing season in Rockville?
Measured between 28°F hard freezes, Rockville sees about 262 frost-free days — roughly Mar 3 through Nov 20, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 24 to Nov 6, about 227 days.
Is the soil safe to grow vegetables in Rockville?
The federal record around Rockville is light — 15 documented sites across the 9 federal source types we checked, mostly Underground Storage Tanks entries (7), the nearest Nitrate record about 1.6 miles out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do I protect my plants from frost in Rockville?
From about Oct 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 Nov 20 (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 20. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Rockville's scale — its 8a band and its 262-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 ~262-day season between 28°F freezes, the 5,416 acres it covers and 15 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Rockville's own USDA hardiness band, zones 8aUSDA PHZM 2023
- Rockville's own 28°F hard-freeze dates, about Mar 3 and Nov 20 and the ~262-day span between themNOAA 1991–2020 Climate Normals
- 15 documented contamination sites on the federal record near Rockville, the closest Nitrate record about 1.6 miles out from the town centreFederal environmental registers
- Rockville's boundary and the 5,416 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8a and a ~262-day seasonGrowable Ground crop-matching engine
- Rockville sits in the Colorado Plateaus — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Rockville's 5,416 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 Utah grower plans around — written at state scale, so they stay on the state guidefrom Utah
- 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 Rockville's 5,416 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 5,416 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 1.6 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 Utah
Wider growing context
What grows across UtahRockville sits outside our named growing regions, so Utah as a whole is its closest context here.
Nearby growing guides