Green Castle, Missouri, sits in USDA hardiness zone 5b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Growers here do well with cabbage, cranberry, lavender, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Green Castle, 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 Green Castle 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 Green Castle — soil, climate, flood, and parcel records. How we handle your address.
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Green Castle — the short answer
Green Castle, Missouri: USDA zone 5b, about 203 days between hard freezes, across 286 acres of city.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 6
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~203
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 286 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 5b is Green Castle's average, not your lot's — a low corner or a tree line moves it. Against Green Castle's 203-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Green Castle
Each reading below is measured for Green Castle itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredGreen Castle runs about 203 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
MeasuredGreen Castle sits in USDA hardiness zone 5b.
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 Green Castle is in
Green Castle sits in the Central Irregular Plains — EPA Level III, inside the wider Great Plains. That is read at Green Castle's own centroid rather than borrowed from Sullivan County.
What Grows in Green Castle
Every plant below cleared Green Castle's own zone 5b and its 203-day season. Each card opens that plant's Missouri profile. How we score.
Is it too late to plant in Green Castle?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 9; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 6 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 26 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
What's on the federal record near Green Castle
Closest first, within ~10 miles of Green Castle. Listing isn't leaking, and distance isn't exposure.
- SMITHFIELD, VALLEY VIEW FARMCAFO · 3.2 mi
- MFA PROPANEUnderground Storage Tanks · 4.1 mi
- CO-OP OIL & GAS COUnderground Storage Tanks · 4.1 mi
- PRIVITT'S MFA SERVICEUnderground Storage Tanks · 4.2 mi
- GREEN CITY MAINT LOTUnderground Storage Tanks · 4.2 mi
- PHILLIP SMITHCAFO · 4.5 mi
- L AND D FARMSCAFO · 4.9 mi
- ADAIR COUNTY PWSD 1PFAS · 5.9 mi
- SHAFER FARMSCAFO · 6.1 mi
- KING FARMSCAFO · 7.7 mi
- LAWRENCE VASEYCAFO · 8.0 mi
- DANNY'S SERVICE STATIONUnderground Storage Tanks · 9.2 mi
3 more sites are on the record inside the same radius. See them on the map
Measured from Green Castle'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 Green Castle.
Total Sites
16
within ~10 miles of Green Castle
Risk Level
Moderate
Highest-severity
7 concentrated animal feeding operations
Sources Checked
within ~10 miles of Green Castle
Severity Distribution
within ~10 miles of Green Castle
Highest-Severity Sites
Know Before You Grow
- •Large animal operations push nitrates and bacteria downstream. Below one, test your water.
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Green Castle
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 Green Castle average
Your land is one point inside Green Castle
Everything above resolves to Green Castle as a whole — one PHZM band and one 28°F frost record, read across 286 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 Green Castle Average
Green Castle Average
- ●USDA Zones 5b, averaged across Green Castle
- ●One soil character for all of Green Castle
- ●Frost dates read at Green Castle's scale: Apr 6 to Oct 26
YOUR Parcel
- ✓Your exact zone, not Green Castle's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Green Castle
Pull a site-specific report for your exact address in Green Castle, Missouri — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Green Castle averages can't show:
We read public map data around Green Castle — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Green Castle average
How we know this about Green Castle
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 Green Castle’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 Green Castle
When does frost risk typically end in Green Castle?
The last hard freeze (28°F) in Green Castle typically lands around Apr 6, 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 27.
When is the first frost in Green Castle?
The first hard freeze (28°F) in Green Castle typically arrives around Oct 26, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 12, so the watching starts about Sep 26 — about 203 days after the spring freeze cleared.
How long is the growing season in Green Castle?
Measured between 28°F hard freezes, Green Castle sees about 203 frost-free days — roughly Apr 6 through Oct 26, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 27 to Oct 12, about 168 days.
Is the soil safe to grow vegetables in Green Castle?
The federal record around Green Castle shows 16 documented sites, mostly CAFO entries (7), the nearest CAFO record about 3.2 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 Green Castle?
From about Sep 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 Oct 26 (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 Oct 26. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Green Castle's scale — its 5b band and its 203-day season. Your yard writes its own version of Green Castle'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 Green Castle’s own scale
6 of the readings below were taken at Green Castle's own scale — its own ~203-day season between 28°F freezes, the 286 acres it covers and 16 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Green Castle's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Green Castle's own 28°F hard-freeze dates, about Apr 6 and Oct 26 and the ~203-day span between themNOAA 1991–2020 Climate Normals
- 16 documented contamination sites on the federal record near Green Castle, the closest CAFO record about 3.2 miles out from the town centreFederal environmental registers
- Green Castle's boundary and the 286 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~203-day seasonGrowable Ground crop-matching engine
- The ecoregion at Green Castle's own centroid, the Central Irregular PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Green Castle's 286 acres read through its county's SSURGO summaryfrom Sullivan County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Sullivan 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 Sullivan County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Green Castle's 286 acreswhy one lot differs from the next →
- Which side of Green Castle you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 286 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest CAFO record about 3.2 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 Green Castle-wide figureread your own land →