Martinsburg, Iowa, sits in USDA hardiness zone 5b — 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, cranberry, lavender, 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 Martinsburg, 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 Martinsburg 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 Martinsburg — soil, climate, flood, and parcel records. How we handle your address.
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Martinsburg — the short answer
Martinsburg, Iowa: USDA zone 5b, about 201 days between hard freezes, across 239 acres of city.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 9
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 27
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~201
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 239 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 Martinsburg's average, not your lot's — a low corner or a tree line moves it. Against Martinsburg's 201-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Martinsburg
Each reading below is measured for Martinsburg itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMartinsburg runs about 201 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
MeasuredMartinsburg 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 Martinsburg is in
Martinsburg sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. That is read at Martinsburg's own centroid rather than borrowed from Keokuk County.
What Grows in Martinsburg
Every plant below cleared Martinsburg's own zone 5b and its 201-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Martinsburg?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 12; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 9 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 27 — 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.
What's on the federal record near Martinsburg
Closest first, within ~10 miles of Martinsburg. Listing isn't leaking, and distance isn't exposure.
- PFANNEBAKERSUnderground Storage Tanks · 650 ft
- HEDRICK OILUnderground Storage Tanks · 650 ft
- STEADY RUN STATIONUnderground Storage Tanks · 1300 ft
- ROBERTSONS STOREUnderground Storage Tanks · 1400 ft
- 075N10W02DCDD 15204 1961Nitrate · 1.6 mi
- 074N13W36BDA 01307 1941Hedrick OldNitrate · 2.9 mi
- KAISER AGRICULTURAL CHEMICALSUnderground Storage Tanks · 3.0 mi
- 074N13W36BDB 03065 1948Hedrick 1Nitrate · 3.0 mi
- 073N12W12CCCC 16667 1963Nitrate · 3.3 mi
- BILL''S STANDARDUnderground Storage Tanks · 3.4 mi
- HEDRICK COMMUNITY SCHOOLUnderground Storage Tanks · 3.4 mi
- 073N12W16CBB 17770 1965Nitrate · 3.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Martinsburg'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 Martinsburg.
Total Sites
67
within ~10 miles of Martinsburg
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Martinsburg
Severity Distribution
within ~10 miles of Martinsburg
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Martinsburg, Nitrate runs higher than the national average — 32 sites within ~10 miles of Martinsburg. 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 Martinsburg
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 Martinsburg average
Your land is one point inside Martinsburg
Everything above resolves to Martinsburg as a whole — one PHZM band and one 28°F frost record, read across 239 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 Martinsburg Average
Martinsburg Average
- ●USDA Zones 5b, averaged across Martinsburg
- ●One soil character for all of Martinsburg
- ●Frost dates read at Martinsburg's scale: Apr 9 to Oct 27
YOUR Parcel
- ✓Your exact zone, not Martinsburg's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Martinsburg
Pull a site-specific report for your exact address in Martinsburg, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Martinsburg averages can't show:
We read public map data around Martinsburg — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Martinsburg average
How we know this about Martinsburg
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 Martinsburg’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 Martinsburg
When does frost risk typically end in Martinsburg?
The last hard freeze (28°F) in Martinsburg typically lands around Apr 9, 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 30.
When is the first frost in Martinsburg?
The first hard freeze (28°F) in Martinsburg typically arrives around Oct 27, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 13, so the watching starts about Sep 27 — about 201 days after the spring freeze cleared.
How long is the growing season in Martinsburg?
Measured between 28°F hard freezes, Martinsburg sees about 201 frost-free days — roughly Apr 9 through Oct 27, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 30 to Oct 13, about 166 days.
Is the soil safe to grow vegetables in Martinsburg?
The federal record around Martinsburg shows 67 documented sites, mostly Nitrate entries (32), the nearest Underground Storage Tanks record about 0.1 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 Martinsburg?
From about Sep 27 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 27 (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 27. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Martinsburg's scale — its 5b band and its 201-day season. Your yard writes its own version of Martinsburg'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 Martinsburg’s own scale
6 of the readings below were taken at Martinsburg's own scale — its own ~201-day season between 28°F freezes, the 239 acres it covers and 67 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Martinsburg's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Martinsburg's own 28°F hard-freeze dates, about Apr 9 and Oct 27 and the ~201-day span between themNOAA 1991–2020 Climate Normals
- 67 documented contamination sites on the federal record near Martinsburg, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Martinsburg's boundary and the 239 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~201-day seasonGrowable Ground crop-matching engine
- The ecoregion at Martinsburg's own centroid, the Western Corn Belt PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Martinsburg's 239 acres read through its county's SSURGO summaryfrom Keokuk County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Keokuk County
- The growing challenges every Iowa grower plans around — written at state scale, so they stay on the state guidefrom Iowa
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Keokuk County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Martinsburg's 239 acreswhy one lot differs from the next →
- Which side of Martinsburg you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 239 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 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 Martinsburg-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaMartinsburg sits outside our named growing regions, so Iowa as a whole is its closest context here.
Nearby growing guides