Diamondhead Lake, Iowa, sits in USDA hardiness zone 5b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Among the crops suited to this profile: cabbage, cranberry, lavender, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Diamondhead Lake, 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 Diamondhead Lake 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 Diamondhead Lake — soil, climate, flood, and parcel records. How we handle your address.
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Diamondhead Lake — the short answer
Diamondhead Lake, Iowa: USDA zone 5b, about 191 days between hard freezes, across 623 acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 13
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 21
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~191
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 623 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 Diamondhead Lake's average, not your lot's — a low corner or a tree line moves it. Against Diamondhead Lake's 191-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Diamondhead Lake
Each reading below is measured for Diamondhead Lake itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDiamondhead Lake runs about 191 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredDiamondhead Lake 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 Diamondhead Lake is in
Diamondhead Lake sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. That is read at Diamondhead Lake's own centroid rather than borrowed from Guthrie County.
What Grows in Diamondhead Lake
Every plant below cleared Diamondhead Lake's own zone 5b and its 191-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Diamondhead Lake?
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 Mar 16; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 13 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 21 — long-season crops need about 90 days of runway, quick greens only 30. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
What's on the federal record near Diamondhead Lake
Closest first, within ~10 miles of Diamondhead Lake. Listing isn't leaking, and distance isn't exposure.
- MID AMERICA TRENCHERS LLCBrownfields · 2.7 mi
- CASEY''S GENERAL STORE 95Underground Storage Tanks · 3.0 mi
- DEXTER AUTO SALESUnderground Storage Tanks · 3.1 mi
- SMITH PAINTING INCBrownfields · 3.1 mi
- GLEN GERY BRICK MIDLAND DIVISIONUnderground Storage Tanks · 3.7 mi
- HEARTLAND COOPUnderground Storage Tanks · 3.7 mi
- MOORHEAD SERVICEUnderground Storage Tanks · 3.8 mi
- GLEN-GERY CORPToxics Release Inventory · 3.9 mi
- CASEY''S GENERAL STORE 2553Underground Storage Tanks · 3.9 mi
- CASEY''S GENERAL STORE#0097Underground Storage Tanks · 4.0 mi
- FARMERS COOP ELEVATOR COUnderground Storage Tanks · 4.0 mi
- KETELSEN SERVICEUnderground Storage Tanks · 4.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Diamondhead Lake'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 Diamondhead Lake.
Total Sites
74
within ~10 miles of Diamondhead Lake
Risk Level
Moderate
Highest-severity
4 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Diamondhead Lake
Severity Distribution
within ~10 miles of Diamondhead Lake
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Diamondhead Lake, Nitrate runs higher than the national average — 20 sites within ~10 miles of Diamondhead Lake. 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 Diamondhead Lake
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 Diamondhead Lake average
Your land is one point inside Diamondhead Lake
Everything above resolves to Diamondhead Lake as a whole — one PHZM band and one 28°F frost record, read across 623 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 Diamondhead Lake Average
Diamondhead Lake Average
- ●USDA Zones 5b, averaged across Diamondhead Lake
- ●One soil character for all of Diamondhead Lake
- ●Frost dates read at Diamondhead Lake's scale: Apr 13 to Oct 21
YOUR Parcel
- ✓Your exact zone, not Diamondhead Lake's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Diamondhead Lake
Pull a site-specific report for your exact address in Diamondhead Lake, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Diamondhead Lake averages can't show:
We read public map data around Diamondhead Lake — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Diamondhead Lake average
How we know this about Diamondhead Lake
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 Diamondhead Lake’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 Diamondhead Lake
When does frost risk typically end in Diamondhead Lake?
The last hard freeze (28°F) in Diamondhead Lake typically lands around Apr 13, 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 May 4.
When is the first frost in Diamondhead Lake?
The first hard freeze (28°F) in Diamondhead Lake typically arrives around Oct 21, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 7, so the watching starts about Sep 21 — about 191 days after the spring freeze cleared.
How long is the growing season in Diamondhead Lake?
Measured between 28°F hard freezes, Diamondhead Lake sees about 191 frost-free days — roughly Apr 13 through Oct 21, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 4 to Oct 7, about 156 days.
Is the soil safe to grow vegetables in Diamondhead Lake?
The federal record around Diamondhead Lake shows 74 documented sites, mostly Underground Storage Tanks entries (40), the nearest Brownfields record about 2.7 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 Diamondhead Lake?
From about Sep 21 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 21 (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 21. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Diamondhead Lake's scale — its 5b band and its 191-day season. Your yard writes its own version of Diamondhead Lake'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 Diamondhead Lake’s own scale
6 of the readings below were taken at Diamondhead Lake's own scale — its own ~191-day season between 28°F freezes, the 623 acres it covers and 74 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Diamondhead Lake's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Diamondhead Lake's own 28°F hard-freeze dates, about Apr 13 and Oct 21 and the ~191-day span between themNOAA 1991–2020 Climate Normals
- 74 documented contamination sites on the federal record near Diamondhead Lake, the closest Brownfields record about 2.7 miles out from the town centreFederal environmental registers
- Diamondhead Lake's boundary and the 623 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~191-day seasonGrowable Ground crop-matching engine
- The ecoregion at Diamondhead Lake'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 Diamondhead Lake's 623 acres read through its county's SSURGO summaryfrom Guthrie County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Guthrie 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 Guthrie County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Diamondhead Lake's 623 acreswhy one lot differs from the next →
- Which side of Diamondhead Lake you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 623 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 2.7 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 Diamondhead Lake-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaDiamondhead Lake sits outside our named growing regions, so Iowa as a whole is its closest context here.