Tamms, Illinois, sits in USDA hardiness zone 7a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Reliable performers under these conditions include cabbage, hazelnut, california poppy, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Tamms, 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 Tamms 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 Tamms — soil, climate, flood, and parcel records. How we handle your address.
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Tamms — the short answer
Tamms, Illinois: USDA zone 7a, about 244 days between hard freezes, across 1K acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 19
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 18
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~244
- 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 7a is Tamms's average, not your lot's — a low corner or a tree line moves it. Against Tamms's 244-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Tamms
Each reading below is measured for Tamms itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredTamms runs about 244 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
MeasuredTamms sits in USDA hardiness zone 7a.
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 Tamms is in
Tamms sits in the Interior River Valleys and Hills — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Tamms's own centroid rather than borrowed from Alexander County.
What Grows in Tamms
Every plant below cleared Tamms's own zone 7a and its 244-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Tamms?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Feb 19; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 19 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 18 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.
What's on the federal record near Tamms
Closest first, within ~10 miles of Tamms. Listing isn't leaking, and distance isn't exposure.
- Egyptian School Dist #5Underground Storage Tanks · 2000 ft
- Unimin Specialty Minerals IncUnderground Storage Tanks · 2000 ft
- Huffman's ServiceUnderground Storage Tanks · 2400 ft
- Butcher BlockUnderground Storage Tanks · 2500 ft
- Jordan DonaldUnderground Storage Tanks · 0.6 mi
- Honey Bros GarageUnderground Storage Tanks · 0.6 mi
- Pulaski/Sandusky Rd and IL-127Nitrate · 2.6 mi
- 14S 1W-33.2hNitrate · 3.3 mi
- Heilig BrosUnderground Storage Tanks · 4.1 mi
- Cypress Creek Wildlife RefugeUnderground Storage Tanks · 4.1 mi
- Terry PalmisanoUnderground Storage Tanks · 4.1 mi
- 14S 1W-35.5dNitrate · 4.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Tamms'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 Tamms.
Severity Distribution
within ~10 miles of Tamms
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Tamms, two things run higher than the national average within ~10 miles of Tamms — Underground Storage Tanks (36 sites) and Nitrate (14 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Tamms
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 Tamms average
Your land is one point inside Tamms
Everything above resolves to Tamms 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 Tamms Average
Tamms Average
- ●USDA Zones 7a, averaged across Tamms
- ●One soil character for all of Tamms
- ●Frost dates read at Tamms's scale: Mar 19 to Nov 18
YOUR Parcel
- ✓Your exact zone, not Tamms's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Tamms
Pull a site-specific report for your exact address in Tamms, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Tamms averages can't show:
We read public map data around Tamms — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Tamms average
How we know this about Tamms
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 Tamms’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 Tamms
When does frost risk typically end in Tamms?
The last hard freeze (28°F) in Tamms typically lands around Mar 19, 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 9.
When is the first frost in Tamms?
The first hard freeze (28°F) in Tamms typically arrives around Nov 18, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 4, so the watching starts about Oct 19 — about 244 days after the spring freeze cleared.
How long is the growing season in Tamms?
Measured between 28°F hard freezes, Tamms sees about 244 frost-free days — roughly Mar 19 through Nov 18, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 9 to Nov 4, about 209 days.
Is the soil safe to grow vegetables in Tamms?
The federal record around Tamms shows 53 documented sites, mostly Underground Storage Tanks entries (36), 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 Tamms?
From about Oct 19 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 18 (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 18. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Tamms's scale — its 7a band and its 244-day season. Your yard writes its own version of Tamms'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 Tamms’s own scale
6 of the readings below were taken at Tamms's own scale — its own ~244-day season between 28°F freezes, the 1,492 acres it covers and 53 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Tamms's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Tamms's own 28°F hard-freeze dates, about Mar 19 and Nov 18 and the ~244-day span between themNOAA 1991–2020 Climate Normals
- 53 documented contamination sites on the federal record near Tamms, the closest Underground Storage Tanks record about 0.4 miles out from the town centreFederal environmental registers
- Tamms's boundary and the 1,492 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~244-day seasonGrowable Ground crop-matching engine
- The ecoregion at Tamms's own centroid, the Interior River Valleys and HillsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Tamms's 1,492 acres read through its county's SSURGO summaryfrom Alexander County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Alexander County
- The growing challenges every Illinois grower plans around — written at state scale, so they stay on the state guidefrom Illinois
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Alexander County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Tamms's 1,492 acreswhy one lot differs from the next →
- Which side of Tamms you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,492 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 Tamms-wide figureread your own land →