Arnold, Missouri, sits in USDA hardiness zone 7a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Expect cabbage, hazelnut, california poppy, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Arnold, 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 Arnold 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 Arnold — soil, climate, flood, and parcel records. How we handle your address.
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Arnold — the short answer
Arnold, Missouri: USDA zone 7a, about 233 days between hard freezes, across 7K acres of city.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 23
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 11
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~233
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 7K 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 7a is Arnold's average, not your lot's — a low corner or a tree line moves it. Against Arnold's 233-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Arnold
Each reading below is measured for Arnold itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredArnold runs about 233 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredArnold sits in USDA hardiness zone 7a.
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 Arnold is in
Arnold sits in the Ozark Highlands — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Arnold's own centroid rather than borrowed from Jefferson County.
What Grows in Arnold
Every plant below cleared Arnold's own zone 7a and its 233-day season. Each card opens that plant's Missouri profile. How we score.
Is it too late to plant in Arnold?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Feb 23; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 23 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 11 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.
Documented around Arnold
Survey cells within 31 miles of Arnold checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 257 miles off. What to watch for.
What's on the federal record near Arnold
Closest first, within ~10 miles of Arnold. Listing isn't leaking, and distance isn't exposure.
- T43N R06E 29DCC1Nitrate · 500 ft
- CITY OF ARNOLDUnderground Storage Tanks · 2200 ft
- ARNOLD AUTO BODYUnderground Storage Tanks · 0.5 mi
- GARY & ROGER L LINK INCUnderground Storage Tanks · 0.5 mi
- ARNOLD COLLISION EXPERTSBrownfields · 0.5 mi
- ARNOLD GAS & FOODUnderground Storage Tanks · 0.6 mi
- ARNOLD AUTOMOTIVE REPAIR & TIREUnderground Storage Tanks · 0.7 mi
- FISCA OIL CO INCUnderground Storage Tanks · 0.7 mi
- DOBBS AUTO CENTERUnderground Storage Tanks · 0.7 mi
- METAL CONTAINER CORPORATIONUnderground Storage Tanks · 0.8 mi
- T43N R06E 28BCD1Nitrate · 0.8 mi
- RONALD ENGELBACHUnderground Storage Tanks · 0.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Arnold'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 Arnold.
Sources Checked
within ~10 miles of Arnold
Severity Distribution
within ~10 miles of Arnold
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.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Arnold
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 Arnold average
Your land is one point inside Arnold
Everything above resolves to Arnold as a whole — one PHZM band and one 28°F frost record, read across 7K 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 Arnold Average
Arnold Average
- ●USDA Zones 7a, averaged across Arnold
- ●One soil character for all of Arnold
- ●Frost dates read at Arnold's scale: Mar 23 to Nov 11
YOUR Parcel
- ✓Your exact zone, not Arnold's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Arnold
Pull a site-specific report for your exact address in Arnold, Missouri — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Arnold averages can't show:
We read public map data around Arnold — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Arnold average
How we know this about Arnold
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 Arnold’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 Arnold
When does frost risk typically end in Arnold?
The last hard freeze (28°F) in Arnold typically lands around Mar 23, 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 Apr 13.
When is the first frost in Arnold?
The first hard freeze (28°F) in Arnold typically arrives around Nov 11, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 28, so the watching starts about Oct 12 — about 233 days after the spring freeze cleared.
How long is the growing season in Arnold?
Measured between 28°F hard freezes, Arnold sees about 233 frost-free days — roughly Mar 23 through Nov 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 13 to Oct 28, about 198 days.
Is the soil safe to grow vegetables in Arnold?
The federal record around Arnold is a meaningful one — 1,158 documented sites, mostly Underground Storage Tanks entries (566), the nearest Nitrate record under a tenth of a mile 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 Arnold?
From about Oct 12 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 11 (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 11. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Arnold's scale — its 7a band and its 233-day season. Your yard writes its own version of Arnold'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 Arnold’s own scale
7 of the readings below were taken at Arnold's own scale — its own ~233-day season between 28°F freezes, the 7,378 acres it covers and 1,158 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Arnold's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Arnold's own 28°F hard-freeze dates, about Mar 23 and Nov 11 and the ~233-day span between themNOAA 1991–2020 Climate Normals
- 1,158 documented contamination sites on the federal record near Arnold, the closest Nitrate record under a tenth of a mile out from the town centreFederal environmental registers
- Arnold's boundary and the 7,378 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~233-day seasonGrowable Ground crop-matching engine
- The ecoregion at Arnold's own centroid, the Ozark HighlandsUS EPA Level III Ecoregions
- Lanternfly survey cells around Arnold checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Arnold's 7,378 acres read through its county's SSURGO summaryfrom Jefferson County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Jefferson 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 Jefferson County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Arnold's 7,378 acreswhy one lot differs from the next →
- Which side of Arnold you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 7,378 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record under a tenth of a mile 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 Arnold-wide figureread your own land →
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