Calvert, Texas, sits in USDA hardiness zone 9a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
On paper, artichoke, fig, california poppy, and cabbage all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Calvert, 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 Calvert 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 Calvert — soil, climate, flood, and parcel records. How we handle your address.
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Calvert — the short answer
Calvert, Texas: USDA zone 9a, about 288 days between hard freezes, across 2K acres of city.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 17
- Robertson County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 2
- Robertson County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~288
- Robertson County normal — NOAA 1991–2020, nearest to this town
- City area
- 2K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Robertson County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9a is Calvert's average, not your lot's — a low corner or a tree line moves it. Against Calvert's 288-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Calvert
Each reading below is measured for Calvert itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsCalvert runs about 288 days between hard freezes (read from Robertson County, the closest normal to Calvert) — 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
MeasuredCalvert sits in USDA hardiness zone 9a.
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 Calvert is in
Calvert sits in the East Central Texas Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Calvert's own centroid rather than borrowed from Robertson County.
What Grows in Calvert
Every plant below cleared Calvert's own zone 9a and its 288-day season. Each card opens that plant's Texas profile. How we score.
Is it too late to plant in Calvert?
Almost never — the real question is what to plant next. 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 Dec 2 — 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 Calvert
Closest first, within ~10 miles of Calvert. Listing isn't leaking, and distance isn't exposure.
- FONTANA FORD SALESUnderground Storage Tanks · 850 ft
- FAMILY DOLLAR # 10614Brownfields · 850 ft
- RB FOOD MARTUnderground Storage Tanks · 900 ft
- CITY GARAGE & EQUIPMENTUnderground Storage Tanks · 1300 ft
- FLORIDA EXXON PARTS & TIRESUnderground Storage Tanks · 2300 ft
- J&J GROCERYUnderground Storage Tanks · 2300 ft
- MIKES COUNTRY STORE 8Underground Storage Tanks · 2600 ft
- 629 INVESTMENTSUnderground Storage Tanks · 0.6 mi
- JOSEPH C FONTANAUnderground Storage Tanks · 0.6 mi
- WK-59-03-305Nitrate · 2.3 mi
- CITY OF CALVERTPFAS · 2.4 mi
- HEARNE TERMINALBrownfields · 5.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Calvert'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 Calvert.
Total Sites
97
within ~10 miles of Calvert
Risk Level
Moderate
Highest-severity
5 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Calvert
Severity Distribution
within ~10 miles of Calvert
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Calvert, Underground Storage Tanks runs higher than the national average — 75 sites within ~10 miles of Calvert. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Calvert
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 Calvert average
Your land is one point inside Calvert
Everything above resolves to Calvert as a whole — one PHZM band, read across 2K acres, with hard-freeze dates borrowed from Robertson County’s record because no 30-year normal resolves at this city’s own centroid. 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 Calvert Average
Calvert Average
- ●USDA Zones 9a, averaged across Calvert
- ●One soil character for all of Calvert
- ●Frost dates read at Calvert's scale: Feb 17 to Dec 2
YOUR Parcel
- ✓Your exact zone, not Calvert's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Calvert
Pull a site-specific report for your exact address in Calvert, Texas — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Calvert averages can't show:
We read public map data around Calvert — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Calvert average
How we know this about Calvert
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 Robertson County’s record, because none resolves here; 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 Calvert
When does frost risk typically end in Calvert?
The last hard freeze (28°F) in Calvert 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.
When is the first frost in Calvert?
The first hard freeze (28°F) in Calvert typically arrives around Dec 2, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 18, so the watching starts about Nov 2 — about 288 days after the spring freeze cleared.
How long is the growing season in Calvert?
Measured between 28°F hard freezes, Calvert sees about 288 frost-free days — roughly Feb 17 through Dec 2, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 10 to Nov 18, about 253 days.
Is the soil safe to grow vegetables in Calvert?
The federal record around Calvert shows 97 documented sites, mostly Underground Storage Tanks entries (75), the nearest Underground Storage Tanks record about 0.2 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in Calvert?
From about Nov 2 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 Dec 2 (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 Dec 2. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Calvert's scale — its 9a band and its 288-day season. Your yard writes its own version of Calvert'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 Calvert’s own scale
5 of the readings below were taken at Calvert's own scale — the 2,490 acres it covers and 97 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Calvert's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 97 documented contamination sites on the federal record near Calvert, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Calvert's boundary and the 2,490 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9a and a ~288-day seasonGrowable Ground crop-matching engine
- The ecoregion at Calvert's own centroid, the East Central Texas PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Calvert has no normal of its own, so its county's is the closest measured readfrom Robertson County
- Soil character — no town-scale survey exists, so Calvert's 2,490 acres read through its county's SSURGO summaryfrom Robertson County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Robertson County
- The growing challenges every Texas grower plans around — written at state scale, so they stay on the state guidefrom Texas
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Robertson County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Calvert's 2,490 acreswhy one lot differs from the next →
- Which side of Calvert you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,490 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks 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 Calvert-wide figureread your own land →
More in Texas
Wider growing context
What grows across TexasCalvert sits outside our named growing regions, so Texas as a whole is its closest context here.
Nearby growing guides