Rockwall County, in Texas, sits in USDA hardiness zone 8b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
The conditions favor cabbage, fig, california poppy, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Rockwall County lies within the Blackland Prairie — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Rockwall County holds more than one microclimate.
Soils and elevations shift across Rockwall County, so your frost dates and drainage aren't the county average. 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 Rockwall County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Rockwall County — the short answer
Rockwall County, Texas: USDA zone 8b, about 285 days between hard freezes, across 81K acres.
- USDA zone
- 8b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 17
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 29
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~285
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 81K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 8b is Rockwall County's average, not your lot's — a low corner or a tree line moves it. Against Rockwall County's 285-day season, see what your own ground reads.
Heat and winter chill in Rockwall County
Across a year, Rockwall County accumulates about 5,831 growing degree days above 50°F, about 7 more than the middle Texas county — ahead of 130 of Texas’s 254 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Winter banks about 1,012 hours below 45°F, 83 fewer than the Texas middle of 1,095. Chill is what tells a fruit tree its dormancy is over, and it is set by climate rather than by anything you can build.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Rockwall County
Across Rockwall County, the ground is predominantly Vertisols, where Houston Black, Heiden, and Burleson are the most extensive named soil series. The soil is generally moderately well drained with a clay surface. Topsoil pH runs about 7.9–8.2, moderately alkaline. Rainfall drains through hydrologic group D soils.
Soil order
Vertisols
Drainage
Moderately well drained
Prime farmland
63%
Hydric soils
6%
Soil still varies lot by lot — soil types explained.
How the ground varies across Rockwall County
The USDA soil survey maps 63% of Rockwall County as moderately well drained — but another 23% drains differently: 23% well drained.
Houston Black is the most extensive named soil at 47% of mapped acres, then Heiden (12%) and Burleson (10%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Rockwall County
Each reading below is measured for Rockwall County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Rockwall County are moderately well drained, in hydrologic group D — roughly the middle of the drainage range.
This is close to the middle most vegetables prefer: it holds enough water to carry a crop between rains without staying waterlogged. The catch is that a wet spring or a low corner can still tip it soggy.
Plant on the site as-is for most crops, but keep the lowest, slowest-draining beds for moisture-tolerant plantings.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Rockwall County runs about pH 7.9–8.2, on the alkaline side.
Many vegetables cope, but acid-lovers like blueberries struggle, and iron and manganese lock up above about pH 7.5 — leaves yellow between the veins even in rich soil.
Elemental sulfur and generous organic matter lower pH slowly for the beds that need it; test first so you add only what the soil actually calls for.
USDA NRCS SSURGO
Season length
MeasuredRockwall County runs about 285 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
MeasuredRockwall County sits in USDA hardiness zone 8b.
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 Rockwall County is in
Rockwall County sits in the Texas Blackland Prairies — EPA Level III, inside the wider Great Plains. One consistent ecological setting across the whole county.
What Grows in Rockwall County
We scored all 1,086 plants against Rockwall County's own USDA zone 8b and its own 285-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Texas profile.
Is it too late to plant in Rockwall County?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Jan 20; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 17 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 29 — 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.
Documented around Rockwall County
- monarch butterfly11 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Rockwall County
USGS estimates 16,131 lb of Glyphosate on Rockwall County farmland in 2019, its largest by weight, ahead of Metolachlor & Metolachlor-s (6,055 lb) and Atrazine (4,692 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Rockwall County — and how to grow with it.
We checked the federal record across Rockwall County — 147 documented sites across 5 of the 9 source types we track.
The most significant on record: 1 Superfund site (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Rockwall County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Rockwall County
Closest first, across Rockwall County. Listing isn't leaking, and distance isn't exposure.
- ONE STOP 148Underground Storage Tanks · 1600 ft
- ROYSE CITY ISDUnderground Storage Tanks · 1600 ft
- HANDY CORNERUnderground Storage Tanks · 1600 ft
- ANDREWS FORDUnderground Storage Tanks · 1600 ft
- RAS 6 7445Underground Storage Tanks · 1600 ft
- LATTIMORE MATERIALS CORP - ROCKWALL RMToxics Release Inventory · 2100 ft
- GATEWAY 19Underground Storage Tanks · 0.5 mi
- EKJ ENTERPRISES LPToxics Release Inventory · 0.6 mi
- EKJ ENTERPRISES LP DBA COL-MET SPRAY BOOTHSToxics Release Inventory · 1.1 mi
- 7-ELEVEN STORE 35996Underground Storage Tanks · 1.2 mi
- LOVES COUNTRY STORE 283Underground Storage Tanks · 1.4 mi
- CRASH CHAMPIONS LLCBrownfields · 1.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Rockwall County'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 Rockwall County.
Total Sites
147
across Rockwall County
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
across Rockwall County
Severity Distribution
across Rockwall County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Rockwall County, two things run higher than the national average across Rockwall County — PFAS (8 sites) and Toxics Release Inventory (14 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Rockwall County
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 Rockwall County average
Your land is one point inside Rockwall County
Everything above resolves to Rockwall County as a whole — one PHZM band and one county frost record, read across 81K 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 county 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 county average.
Your Lot vs the Rockwall County Average
Rockwall County Average
- ●USDA Zones 8b, averaged across Rockwall County
- ●One soil character for all of Rockwall County
- ●Frost dates read at Rockwall County's scale: Feb 17 to Nov 29
YOUR Parcel
- ✓Your exact zone, not Rockwall County's 8b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Rockwall County
Pull a site-specific report for your exact address in Rockwall County, Texas — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Rockwall County averages can't show:
We read public map data around Rockwall County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Rockwall County average
How we know this about Rockwall County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Rockwall County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Rockwall County
When does frost risk typically end in Rockwall County?
The last hard freeze (28°F) in Rockwall County typically lands around Feb 17, 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 10.
How long is the growing season in Rockwall County?
Measured between 28°F hard freezes, Rockwall County sees about 285 frost-free days — roughly Feb 17 through Nov 29, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 10 to Nov 15, about 250 days.
Is the soil safe to grow vegetables in Rockwall County?
The federal record around Rockwall County is a meaningful one — 147 documented sites, mostly Underground Storage Tanks entries (93), the nearest Underground Storage Tanks 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.
Everything above is measured at Rockwall County's scale — its 8b band and its 285-day season. Your yard writes its own version of Rockwall County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Texas's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Rockwall County’s own scale
9 of the readings below were taken at Rockwall County's own scale — its own ~285-day span between 28°F freezes, the 3 most extensive soil series mapped here and 147 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Rockwall County's own USDA hardiness band, zones 8bUSDA PHZM 2023
- Rockwall County's own 28°F hard-freeze dates and its ~285-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Rockwall CountyUSDA NRCS SSURGO
- 147 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 0.3 miles outFederal environmental registers
- Rockwall County's boundary and the 81,427 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8b and a ~285-day seasonGrowable Ground crop-matching engine
- Rockwall County sitting wholly inside the Texas Blackland PrairiesUS EPA Level III Ecoregions
- Open occurrence records documented in Rockwall County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Rockwall County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Texas grower plans around — written at state scale, so they stay on the state guidefrom Texas
What this page can’t tell you
- How the season shifts across Rockwall County — the ~285 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Rockwall County's 81,427 acreswhy one lot differs from the next →
- Which of those 147 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Rockwall Countyread your own land →