Harlan, Indiana, sits in USDA hardiness zone 6a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Well-matched crops include cabbage, hazelnut, 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 Harlan, 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 Harlan 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 Harlan — soil, climate, flood, and parcel records. How we handle your address.
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Harlan — the short answer
Harlan, Indiana: USDA zone 6a, about 200 days between hard freezes, across 2K acres of town.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 12
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~200
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 2K 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 Harlan's average, not your lot's — a low corner or a tree line moves it. Against Harlan's 200-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Harlan
Each reading below is measured for Harlan itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredHarlan runs about 200 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
MeasuredHarlan 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 Harlan is in
Harlan sits in the Eastern Corn Belt Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Harlan's own centroid rather than borrowed from Allen County.
What Grows in Harlan
Every plant below cleared Harlan's own zone 6a and its 200-day season. Each card opens that plant's Indiana profile. How we score.
Is it too late to plant in Harlan?
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 15; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 12 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 29 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
Documented around Harlan
Spotted lanternfly documented 15 miles from Harlan, first recorded 2023. What to watch for.
What's on the federal record near Harlan
Closest first, within ~10 miles of Harlan. Listing isn't leaking, and distance isn't exposure.
- MILLCREEK INCBrownfields · 550 ft
- SPRINGFIELD ENTERPRISES INCORPORATEDUnderground Storage Tanks · 950 ft
- Harlan MarathonUnderground Storage Tanks · 1300 ft
- Combined Talents IncorporatedUnderground Storage Tanks · 1300 ft
- Dutch Made IncorporatedUnderground Storage Tanks · 1500 ft
- HARLAN ELEMENTARY SCHOOLUnderground Storage Tanks · 1800 ft
- Harlan Cabinets IncorporatedUnderground Storage Tanks · 2400 ft
- HARLAN CABINETS INCORPORATEDToxics Release Inventory · 2400 ft
- HARLAN CABINETS INCORPORATEDBrownfields · 2400 ft
- Harlan Bulk Plant & Filling StationUnderground Storage Tanks · 0.7 mi
- MILLER CABINETRY & FURNITURE LLCBrownfields · 0.8 mi
- DUTCH MADE CABINETS LLCToxics Release Inventory · 2.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Harlan'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 Harlan.
Total Sites
237
within ~10 miles of Harlan
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Harlan
Severity Distribution
within ~10 miles of Harlan
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Harlan, two things run higher than the national average within ~10 miles of Harlan — Toxics Release Inventory (27 sites) and PFAS (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.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Harlan
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 Harlan average
Your land is one point inside Harlan
Everything above resolves to Harlan as a whole — one PHZM band and one 28°F frost record, read across 2K 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 Harlan Average
Harlan Average
- ●USDA Zones 6a, averaged across Harlan
- ●One soil character for all of Harlan
- ●Frost dates read at Harlan's scale: Apr 12 to Oct 29
YOUR Parcel
- ✓Your exact zone, not Harlan's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Harlan
Pull a site-specific report for your exact address in Harlan, Indiana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Harlan averages can't show:
We read public map data around Harlan — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Harlan average
How we know this about Harlan
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 Harlan’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 Harlan
When does frost risk typically end in Harlan?
The last hard freeze (28°F) in Harlan typically lands around Apr 12, 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 3.
When is the first frost in Harlan?
The first hard freeze (28°F) in Harlan typically arrives around Oct 29, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 15, so the watching starts about Sep 29 — about 200 days after the spring freeze cleared.
How long is the growing season in Harlan?
Measured between 28°F hard freezes, Harlan sees about 200 frost-free days — roughly Apr 12 through Oct 29, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 3 to Oct 15, about 165 days.
Is the soil safe to grow vegetables in Harlan?
The federal record around Harlan is a meaningful one — 237 documented sites, mostly Underground Storage Tanks entries (126), the nearest Brownfields 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 Harlan?
From about Sep 29 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 29 (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 29. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Harlan's scale — its 6a band and its 200-day season. Your yard writes its own version of Harlan'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 Harlan’s own scale
7 of the readings below were taken at Harlan's own scale — its own ~200-day season between 28°F freezes, the 2,227 acres it covers and 237 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Harlan's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Harlan's own 28°F hard-freeze dates, about Apr 12 and Oct 29 and the ~200-day span between themNOAA 1991–2020 Climate Normals
- 237 documented contamination sites on the federal record near Harlan, the closest Brownfields record about 0.1 miles out from the town centreFederal environmental registers
- Harlan's boundary and the 2,227 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~200-day seasonGrowable Ground crop-matching engine
- The ecoregion at Harlan's own centroid, the Eastern Corn Belt PlainsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Harlanlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Harlan's 2,227 acres read through its county's SSURGO summaryfrom Allen County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Allen County
- The growing challenges every Indiana grower plans around — written at state scale, so they stay on the state guidefrom Indiana
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Allen County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Harlan's 2,227 acreswhy one lot differs from the next →
- Which side of Harlan you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,227 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Harlan-wide figureread your own land →
More in Indiana
Wider growing context
What grows across IndianaHarlan sits outside our named growing regions, so Indiana as a whole is its closest context here.
Nearby growing guides