New Haven, Iowa, sits in USDA hardiness zone 5a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Expect cabbage, cranberry, lavender, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in New Haven, 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 New Haven 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 New Haven — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
New Haven — the short answer
New Haven, Iowa: USDA zone 5a, about 182 days between hard freezes, across 1K acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 18
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~182
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 5a is New Haven's average, not your lot's — a low corner or a tree line moves it. Against New Haven's 182-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in New Haven
Each reading below is measured for New Haven itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredNew Haven runs about 182 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
MeasuredNew Haven sits in USDA hardiness zone 5a.
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 New Haven is in
New Haven sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. That is read at New Haven's own centroid rather than borrowed from Mitchell County.
What Grows in New Haven
Every plant below cleared New Haven's own zone 5a and its 182-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in New Haven?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 21; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 18 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 17 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near New Haven
Closest first, within ~10 miles of New Haven. Listing isn't leaking, and distance isn't exposure.
- NEW HAVEN READY MIX INCUnderground Storage Tanks · 2300 ft
- TRENT LINKENMEYERBrownfields · 5.9 mi
- IOWA CONTRACT FABRICATORS, INCBrownfields · 5.9 mi
- IOWA CONTRACT FABRICATORS, INCToxics Release Inventory · 5.9 mi
- BIG OX ENERGY LLCToxics Release Inventory · 6.0 mi
- FARMERS FEED AND GRAINBrownfields · 6.9 mi
- RICEVILLE COMMUNITY SCHOOLUnderground Storage Tanks · 6.9 mi
- ASFAHL FARMSUnderground Storage Tanks · 6.9 mi
- CASEY''S GENERAL STORE 2874Underground Storage Tanks · 7.0 mi
- B & H STANDARDUnderground Storage Tanks · 7.0 mi
- SECONDARY ROADS DEPARTMENTUnderground Storage Tanks · 7.0 mi
- KEELING AUTO REPAIRUnderground Storage Tanks · 7.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from New Haven'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 New Haven.
Total Sites
86
within ~10 miles of New Haven
Risk Level
Moderate
Highest-severity
5 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of New Haven
Severity Distribution
within ~10 miles of New Haven
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 New Haven
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 New Haven average
Your land is one point inside New Haven
Everything above resolves to New Haven as a whole — one PHZM band and one 28°F frost record, read across 1K 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 New Haven Average
New Haven Average
- ●USDA Zones 5a, averaged across New Haven
- ●One soil character for all of New Haven
- ●Frost dates read at New Haven's scale: Apr 18 to Oct 17
YOUR Parcel
- ✓Your exact zone, not New Haven's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in New Haven
Pull a site-specific report for your exact address in New Haven, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that New Haven averages can't show:
We read public map data around New Haven — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the New Haven average
How we know this about New Haven
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 New Haven’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 New Haven
When does frost risk typically end in New Haven?
The last hard freeze (28°F) in New Haven typically lands around Apr 18, 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 9.
When is the first frost in New Haven?
The first hard freeze (28°F) in New Haven typically arrives around Oct 17, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 3, so the watching starts about Sep 17 — about 182 days after the spring freeze cleared.
How long is the growing season in New Haven?
Measured between 28°F hard freezes, New Haven sees about 182 frost-free days — roughly Apr 18 through Oct 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 9 to Oct 3, about 147 days.
Is the soil safe to grow vegetables in New Haven?
The federal record around New Haven shows 86 documented sites, mostly Underground Storage Tanks entries (41), the nearest Underground Storage Tanks record about 0.4 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 New Haven?
From about Sep 17 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 17 (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 17. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at New Haven's scale — its 5a band and its 182-day season. Your yard writes its own version of New Haven'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 New Haven’s own scale
6 of the readings below were taken at New Haven's own scale — its own ~182-day season between 28°F freezes, the 1,233 acres it covers and 86 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- New Haven's own USDA hardiness band, zones 5aUSDA PHZM 2023
- New Haven's own 28°F hard-freeze dates, about Apr 18 and Oct 17 and the ~182-day span between themNOAA 1991–2020 Climate Normals
- 86 documented contamination sites on the federal record near New Haven, the closest Underground Storage Tanks record about 0.4 miles out from the town centreFederal environmental registers
- New Haven's boundary and the 1,233 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~182-day seasonGrowable Ground crop-matching engine
- The ecoregion at New Haven'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 New Haven's 1,233 acres read through its county's SSURGO summaryfrom Mitchell County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Mitchell 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 Mitchell County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among New Haven's 1,233 acreswhy one lot differs from the next →
- Which side of New Haven you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,233 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.4 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 New Haven-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaNew Haven sits outside our named growing regions, so Iowa as a whole is its closest context here.
Nearby growing guides