Plymouth, Indiana, sits in USDA hardiness zone 6a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Expect cabbage, hazelnut, lavender, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Plymouth, 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 Plymouth 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 Plymouth — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Plymouth — the short answer
Plymouth, Indiana: USDA zone 6a, about 204 days between hard freezes, across 5K acres of city.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 10
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 31
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~204
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 5K 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 Plymouth's average, not your lot's — a low corner or a tree line moves it. Against Plymouth's 204-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Plymouth
Each reading below is measured for Plymouth itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredPlymouth runs about 204 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
MeasuredPlymouth 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 Plymouth is in
Plymouth sits in the Southern Michigan/Northern Indiana Drift Plains — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Plymouth's own centroid rather than borrowed from Marshall County.
What Grows in Plymouth
Every plant below cleared Plymouth's own zone 6a and its 204-day season. Each card opens that plant's Indiana profile. How we score.
Is it too late to plant in Plymouth?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 13; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 10 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 31 — 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 Plymouth
Spotted lanternfly documented 19 miles from Plymouth, first recorded 2023. What to watch for.
What's on the federal record near Plymouth
Closest first, within ~10 miles of Plymouth. Listing isn't leaking, and distance isn't exposure.
- DONNITE FIBERBOARDUnderground Storage Tanks · 500 ft
- A SCHULMAN INCORPORATEDToxics Release Inventory · 850 ft
- NW-16 PLYMOUTH, IND.Nitrate · 850 ft
- A Schulman IncorporatedUnderground Storage Tanks · 900 ft
- Plymouth FoundryUnderground Storage Tanks · 1000 ft
- INDIANA HEAT TRANSFER CORP.Toxics Release Inventory · 1000 ft
- INDIANA HEAT TRANSFER CORP.Brownfields · 1000 ft
- DEL MONTE FOODS INC., PLANT 105Brownfields · 1300 ft
- DEL MONTE FOODS INC., PLANT 105Toxics Release Inventory · 1300 ft
- Indiana Heat Transfer CorporationUnderground Storage Tanks · 1300 ft
- PLYMOUTH FOUNDRY INCORPORATEDBrownfields · 1400 ft
- ROGER L WRIGHTUnderground Storage Tanks · 1500 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Plymouth'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 Plymouth.
Total Sites
267
within ~10 miles of Plymouth
Risk Level
Elevated
Highest-severity
30 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Plymouth
Severity Distribution
within ~10 miles of Plymouth
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Plymouth, two things run higher than the national average within ~10 miles of Plymouth — Toxics Release Inventory (30 sites) and Underground Storage Tanks (164 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.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Plymouth
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 Plymouth average
Your land is one point inside Plymouth
Everything above resolves to Plymouth as a whole — one PHZM band and one 28°F frost record, read across 5K 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 Plymouth Average
Plymouth Average
- ●USDA Zones 6a, averaged across Plymouth
- ●One soil character for all of Plymouth
- ●Frost dates read at Plymouth's scale: Apr 10 to Oct 31
YOUR Parcel
- ✓Your exact zone, not Plymouth's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Plymouth
Pull a site-specific report for your exact address in Plymouth, Indiana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Plymouth averages can't show:
We read public map data around Plymouth — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Plymouth average
How we know this about Plymouth
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 Plymouth’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 Plymouth
When does frost risk typically end in Plymouth?
The last hard freeze (28°F) in Plymouth typically lands around Apr 10, 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 1.
When is the first frost in Plymouth?
The first hard freeze (28°F) in Plymouth typically arrives around Oct 31, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 17, so the watching starts about Oct 1 — about 204 days after the spring freeze cleared.
How long is the growing season in Plymouth?
Measured between 28°F hard freezes, Plymouth sees about 204 frost-free days — roughly Apr 10 through Oct 31, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 1 to Oct 17, about 169 days.
Is the soil safe to grow vegetables in Plymouth?
The federal record around Plymouth is a meaningful one — 267 documented sites, mostly Underground Storage Tanks entries (164), the nearest Underground Storage Tanks record under a tenth of a mile 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 Plymouth?
From about Oct 1 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 31 (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 31. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Plymouth's scale — its 6a band and its 204-day season. Your yard writes its own version of Plymouth'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 Plymouth’s own scale
7 of the readings below were taken at Plymouth's own scale — its own ~204-day season between 28°F freezes, the 4,845 acres it covers and 267 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Plymouth's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Plymouth's own 28°F hard-freeze dates, about Apr 10 and Oct 31 and the ~204-day span between themNOAA 1991–2020 Climate Normals
- 267 documented contamination sites on the federal record near Plymouth, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Plymouth's boundary and the 4,845 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~204-day seasonGrowable Ground crop-matching engine
- The ecoregion at Plymouth's own centroid, the Southern Michigan/Northern Indiana Drift PlainsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Plymouthlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Plymouth's 4,845 acres read through its county's SSURGO summaryfrom Marshall County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Marshall 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 Marshall County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Plymouth's 4,845 acreswhy one lot differs from the next →
- Which side of Plymouth you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,845 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile 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 Plymouth-wide figureread your own land →
More in Indiana
Wider growing context
What grows across IndianaPlymouth sits outside our named growing regions, so Indiana as a whole is its closest context here.
Nearby growing guides