Martha, Oklahoma, sits in USDA hardiness zone 7b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Growers here do well with cabbage, prickly pear, california poppy, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Martha, 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 Martha 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 Martha — soil, climate, flood, and parcel records. How we handle your address.
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Martha — the short answer
Martha, Oklahoma: USDA zone 7b, about 238 days between hard freezes, across 161 acres of town.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 13
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~238
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 161 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 7b is Martha's average, not your lot's — a low corner or a tree line moves it. Against Martha's 238-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Martha
Each reading below is measured for Martha itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMartha runs about 238 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
MeasuredMartha sits in USDA hardiness zone 7b.
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 Martha is in
Martha sits in the Central Great Plains — EPA Level III, inside the wider Great Plains. That is read at Martha's own centroid rather than borrowed from Jackson County.
What Grows in Martha
Every plant below cleared Martha's own zone 7b and its 238-day season. Each card opens that plant's Oklahoma profile. How we score.
Is it too late to plant in Martha?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Feb 20; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 20 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 13 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
What's on the federal record near Martha
Closest first, within ~10 miles of Martha. Listing isn't leaking, and distance isn't exposure.
- Martha Station GroceryUnderground Storage Tanks · 400 ft
- Farmers Coop Gin AssociationUnderground Storage Tanks · 1000 ft
- Gary Jones FarmsUnderground Storage Tanks · 2500 ft
- James LaddUnderground Storage Tanks · 1.0 mi
- 03N-21W-15 BBB 1Nitrate · 1.3 mi
- HELENA CHEM COBrownfields · 1.7 mi
- 03N-21W-10 BCC 1Nitrate · 1.8 mi
- R. R. 3 AltusUnderground Storage Tanks · 2.1 mi
- Helena Chemical Co.Underground Storage Tanks · 2.7 mi
- 03N-21W-33 BAD 1Nitrate · 2.8 mi
- Vaughan Farms IncUnderground Storage Tanks · 3.0 mi
- 03N-20W-07 D 1Nitrate · 3.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Martha'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 Martha.
Total Sites
219
within ~10 miles of Martha
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Martha
Severity Distribution
within ~10 miles of Martha
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Martha, Nitrate runs higher than the national average — 106 sites within ~10 miles of Martha. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Martha
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 Martha average
Your land is one point inside Martha
Everything above resolves to Martha as a whole — one PHZM band and one 28°F frost record, read across 161 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 town 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 Martha Average
Martha Average
- ●USDA Zones 7b, averaged across Martha
- ●One soil character for all of Martha
- ●Frost dates read at Martha's scale: Mar 20 to Nov 13
YOUR Parcel
- ✓Your exact zone, not Martha's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Martha
Pull a site-specific report for your exact address in Martha, Oklahoma — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Martha averages can't show:
We read public map data around Martha — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Martha average
How we know this about Martha
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Martha’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 town grain anywhere on this page — there is no town-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 Martha
When does frost risk typically end in Martha?
The last hard freeze (28°F) in Martha typically lands around Mar 20, 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 10.
When is the first frost in Martha?
The first hard freeze (28°F) in Martha typically arrives around Nov 13, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 30, so the watching starts about Oct 14 — about 238 days after the spring freeze cleared.
How long is the growing season in Martha?
Measured between 28°F hard freezes, Martha sees about 238 frost-free days — roughly Mar 20 through Nov 13, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 10 to Oct 30, about 203 days.
Is the soil safe to grow vegetables in Martha?
The federal record around Martha is a meaningful one — 219 documented sites, mostly Nitrate entries (106), the nearest Underground Storage Tanks 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 Martha?
From about Oct 14 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 13 (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 13. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Martha's scale — its 7b band and its 238-day season. Your yard writes its own version of Martha'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 Martha’s own scale
6 of the readings below were taken at Martha's own scale — its own ~238-day season between 28°F freezes, the 161 acres it covers and 219 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Martha's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Martha's own 28°F hard-freeze dates, about Mar 20 and Nov 13 and the ~238-day span between themNOAA 1991–2020 Climate Normals
- 219 documented contamination sites on the federal record near Martha, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Martha's boundary and the 161 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7b and a ~238-day seasonGrowable Ground crop-matching engine
- The ecoregion at Martha's own centroid, the Central Great PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Martha's 161 acres read through its county's SSURGO summaryfrom Jackson County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Jackson County
- The growing challenges every Oklahoma grower plans around — written at state scale, so they stay on the state guidefrom Oklahoma
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Jackson County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Martha's 161 acreswhy one lot differs from the next →
- Which side of Martha you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 161 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks 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 Martha-wide figureread your own land →
More in Oklahoma
Wider growing context
What grows across OklahomaMartha sits outside our named growing regions, so Oklahoma as a whole is its closest context here.
Nearby growing guides