Cardwell, Missouri, sits in USDA hardiness zone 8a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Well-matched crops include cabbage, fig, california poppy, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Even in Cardwell, 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 Cardwell 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 Cardwell — soil, climate, flood, and parcel records. How we handle your address.
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Cardwell — the short answer
Cardwell, Missouri: USDA zone 8a, about 262 days between hard freezes, across 403 acres of city.
- USDA zone
- 8a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 8
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 25
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~262
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 403 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 Cardwell's average, not your lot's — a low corner or a tree line moves it. Against Cardwell's 262-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Cardwell
Each reading below is measured for Cardwell itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCardwell 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
MeasuredCardwell 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 Cardwell is in
Cardwell sits in the Mississippi Alluvial Plain — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Cardwell's own centroid rather than borrowed from Dunklin County.
What Grows in Cardwell
Every plant below cleared Cardwell's own zone 8a and its 262-day season. Each card opens that plant's Missouri profile. How we score.
Is it too late to plant in Cardwell?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 8 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 25 — long-season crops need about 90 days of runway, quick greens only 30. With almost year-round growing weather, timing is about heat and rainfall more than frost — some bench is always in play.
What's on the federal record near Cardwell
Closest first, within ~10 miles of Cardwell. Listing isn't leaking, and distance isn't exposure.
- BOB GILLION SERVICE STATIONUnderground Storage Tanks · 850 ft
- T16N R07E 03DCB1Nitrate · 950 ft
- SOUTHLAND C-9 SCHOOLUnderground Storage Tanks · 1100 ft
- ARBYRD MAINT LOTUnderground Storage Tanks · 2.4 mi
- MR T'S RIVERSIDEUnderground Storage Tanks · 2.7 mi
- ARBYRD WAREHOUSEUnderground Storage Tanks · 2.8 mi
- T16N R08E 06DBD1Nitrate · 3.0 mi
- BOBBY J LANGSTONUnderground Storage Tanks · 3.0 mi
- GUTHRIE'S STATIONUnderground Storage Tanks · 3.0 mi
- T16N R08E 06DBDNitrate · 3.1 mi
- H & RUnderground Storage Tanks · 3.4 mi
- PAUL PHILLIPS STATIONUnderground Storage Tanks · 3.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Cardwell'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 Cardwell.
Sources Checked
within ~10 miles of Cardwell
Severity Distribution
within ~10 miles of Cardwell
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Cardwell, Nitrate runs higher than the national average — 44 sites within ~10 miles of Cardwell. 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 Cardwell
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 Cardwell average
Your land is one point inside Cardwell
Everything above resolves to Cardwell as a whole — one PHZM band and one 28°F frost record, read across 403 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 Cardwell Average
Cardwell Average
- ●USDA Zones 8a, averaged across Cardwell
- ●One soil character for all of Cardwell
- ●Frost dates read at Cardwell's scale: Mar 8 to Nov 25
YOUR Parcel
- ✓Your exact zone, not Cardwell's 8a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Cardwell
Pull a site-specific report for your exact address in Cardwell, Missouri — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Cardwell averages can't show:
We read public map data around Cardwell — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Cardwell average
How we know this about Cardwell
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 Cardwell’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 Cardwell
When does frost risk typically end in Cardwell?
The last hard freeze (28°F) in Cardwell typically lands around Mar 8, 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 29.
When is the first frost in Cardwell?
The first hard freeze (28°F) in Cardwell typically arrives around Nov 25, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 11, so the watching starts about Oct 26 — about 262 days after the spring freeze cleared.
How long is the growing season in Cardwell?
Measured between 28°F hard freezes, Cardwell sees about 262 frost-free days — roughly Mar 8 through Nov 25, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 29 to Nov 11, about 227 days.
Is the soil safe to grow vegetables in Cardwell?
The federal record around Cardwell shows 88 documented sites, mostly Nitrate entries (44), 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 Cardwell?
From about Oct 26 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 25 (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 25. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Cardwell's scale — its 8a band and its 262-day season. Your yard writes its own version of Cardwell'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 Cardwell’s own scale
6 of the readings below were taken at Cardwell's own scale — its own ~262-day season between 28°F freezes, the 403 acres it covers and 88 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Cardwell's own USDA hardiness band, zones 8aUSDA PHZM 2023
- Cardwell's own 28°F hard-freeze dates, about Mar 8 and Nov 25 and the ~262-day span between themNOAA 1991–2020 Climate Normals
- 88 documented contamination sites on the federal record near Cardwell, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Cardwell's boundary and the 403 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8a and a ~262-day seasonGrowable Ground crop-matching engine
- The ecoregion at Cardwell's own centroid, the Mississippi Alluvial PlainUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Cardwell's 403 acres read through its county's SSURGO summaryfrom Dunklin County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Dunklin County
- The growing challenges every Missouri grower plans around — written at state scale, so they stay on the state guidefrom Missouri
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Dunklin County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Cardwell's 403 acreswhy one lot differs from the next →
- Which side of Cardwell you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 403 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 Cardwell-wide figureread your own land →