Franklin, Iowa, sits in USDA hardiness zone 6a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
On paper, cabbage, hazelnut, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Franklin, 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 Franklin 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 Franklin — soil, climate, flood, and parcel records. How we handle your address.
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Franklin — the short answer
Franklin, Iowa: USDA zone 6a, about 214 days between hard freezes, across 100 acres of city.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~214
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 100 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 6a is Franklin's average, not your lot's — a low corner or a tree line moves it. Against Franklin's 214-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Franklin
Each reading below is measured for Franklin itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredFranklin runs about 214 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
MeasuredFranklin sits in USDA hardiness zone 6a.
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 Franklin is in
Franklin sits in the Central Irregular Plains — EPA Level III, inside the wider Great Plains. That is read at Franklin's own centroid rather than borrowed from Lee County.
What Grows in Franklin
Every plant below cleared Franklin's own zone 6a and its 214-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Franklin?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 5; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 2 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 2 — 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 Franklin
Closest first, within ~10 miles of Franklin. Listing isn't leaking, and distance isn't exposure.
- DONNELLSON TIRE SERVICEUnderground Storage Tanks · 750 ft
- GO MARTUnderground Storage Tanks · 1200 ft
- HUNOLD OILUnderground Storage Tanks · 1200 ft
- 068N06W13CAB 01108 1940Nitrate · 1.6 mi
- 068N06W11DAD 06709 1953Nitrate · 2.3 mi
- KIRCHNERS GARAGEBrownfields · 2.8 mi
- 068N06W33CBBA 21320 1969Donnellson 4Nitrate · 3.1 mi
- IOWA DEPARTMENT OF TRANSPORTATIONBrownfields · 3.1 mi
- DAHMS CHEVROLET INCBrownfields · 3.1 mi
- CASEY''S GENERAL STORE 2614Underground Storage Tanks · 3.2 mi
- IDOT MAINT GARAGEUnderground Storage Tanks · 3.2 mi
- 068N06W33CCBB 00184 1925Donnellson 1Nitrate · 3.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Franklin'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 Franklin.
Sources Checked
within ~10 miles of Franklin
Severity Distribution
within ~10 miles of Franklin
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Franklin, two things run higher than the national average within ~10 miles of Franklin — Toxics Release Inventory (18 sites) and Superfund (3 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Franklin
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 Franklin average
Your land is one point inside Franklin
Everything above resolves to Franklin as a whole — one PHZM band and one 28°F frost record, read across 100 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 Franklin Average
Franklin Average
- ●USDA Zones 6a, averaged across Franklin
- ●One soil character for all of Franklin
- ●Frost dates read at Franklin's scale: Apr 2 to Nov 2
YOUR Parcel
- ✓Your exact zone, not Franklin's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Franklin
Pull a site-specific report for your exact address in Franklin, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Franklin averages can't show:
We read public map data around Franklin — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Franklin average
How we know this about Franklin
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 Franklin’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 Franklin
When does frost risk typically end in Franklin?
The last hard freeze (28°F) in Franklin typically lands around Apr 2, 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 23.
When is the first frost in Franklin?
The first hard freeze (28°F) in Franklin typically arrives around Nov 2, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 19, so the watching starts about Oct 3 — about 214 days after the spring freeze cleared.
How long is the growing season in Franklin?
Measured between 28°F hard freezes, Franklin sees about 214 frost-free days — roughly Apr 2 through Nov 2, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 23 to Oct 19, about 179 days.
Is the soil safe to grow vegetables in Franklin?
The federal record around Franklin is a meaningful one — 172 documented sites, mostly Underground Storage Tanks entries (61), the nearest Underground Storage Tanks record about 0.1 miles 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 Franklin?
From about Oct 3 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 2 (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 2. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Franklin's scale — its 6a band and its 214-day season. Your yard writes its own version of Franklin'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 Franklin’s own scale
6 of the readings below were taken at Franklin's own scale — its own ~214-day season between 28°F freezes, the 100 acres it covers and 172 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Franklin's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Franklin's own 28°F hard-freeze dates, about Apr 2 and Nov 2 and the ~214-day span between themNOAA 1991–2020 Climate Normals
- 172 documented contamination sites on the federal record near Franklin, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Franklin's boundary and the 100 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~214-day seasonGrowable Ground crop-matching engine
- The ecoregion at Franklin's own centroid, the Central Irregular PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Franklin's 100 acres read through its county's SSURGO summaryfrom Lee County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Lee 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 Lee County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Franklin's 100 acreswhy one lot differs from the next →
- Which side of Franklin you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 100 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 Franklin-wide figureread your own land →