Dowell, Illinois, sits in USDA hardiness zone 7a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
On paper, cabbage, hazelnut, california poppy, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Dowell, 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 Dowell 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 Dowell — soil, climate, flood, and parcel records. How we handle your address.
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Dowell — the short answer
Dowell, Illinois: USDA zone 7a, about 228 days between hard freezes, across 250 acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 25
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 8
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~228
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 250 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 Dowell's average, not your lot's — a low corner or a tree line moves it. Against Dowell's 228-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Dowell
Each reading below is measured for Dowell itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDowell runs about 228 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
MeasuredDowell 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 Dowell is in
Dowell sits in the Interior River Valleys and Hills — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Dowell's own centroid rather than borrowed from Jackson County.
What Grows in Dowell
Every plant below cleared Dowell's own zone 7a and its 228-day season. Each card opens that plant's Illinois profile. How we score.
Is it too late to plant in Dowell?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 25; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 25 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 8 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
What's on the federal record near Dowell
Closest first, within ~10 miles of Dowell. Listing isn't leaking, and distance isn't exposure.
- Bugaieski Oil Company (Former Val's Pit Stop)Underground Storage Tanks · 1800 ft
- Bedar Citgo ServUnderground Storage Tanks · 0.9 mi
- Casey's General Store #1727Underground Storage Tanks · 1.8 mi
- General WoodworkingUnderground Storage Tanks · 2.0 mi
- Elverado CUSD #196 SchoolsUnderground Storage Tanks · 2.1 mi
- PROFESSIONAL AUTO CENTERBrownfields · 2.2 mi
- ELVERADO HIGH SCHOOLBrownfields · 2.4 mi
- Elkville MobilUnderground Storage Tanks · 2.6 mi
- PRYSMIAN CABLES & SYSTEMS USA LLCToxics Release Inventory · 2.9 mi
- PRYSMIAN CABLES & SYSTEMS USA LLCBrownfields · 2.9 mi
- FENTONS CUSTOM & COLLISION INCBrownfields · 3.1 mi
- Radharani, Inc.Underground Storage Tanks · 3.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Dowell'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 Dowell.
Total Sites
93
within ~10 miles of Dowell
Risk Level
Moderate
Highest-severity
4 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Dowell
Severity Distribution
within ~10 miles of Dowell
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Dowell, Underground Storage Tanks runs higher than the national average — 65 sites within ~10 miles of Dowell. That's not a problem with your land — it's information about it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Dowell
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 Dowell average
Your land is one point inside Dowell
Everything above resolves to Dowell as a whole — one PHZM band and one 28°F frost record, read across 250 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 Dowell Average
Dowell Average
- ●USDA Zones 7a, averaged across Dowell
- ●One soil character for all of Dowell
- ●Frost dates read at Dowell's scale: Mar 25 to Nov 8
YOUR Parcel
- ✓Your exact zone, not Dowell's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Dowell
Pull a site-specific report for your exact address in Dowell, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Dowell averages can't show:
We read public map data around Dowell — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Dowell average
How we know this about Dowell
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 Dowell’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 Dowell
When does frost risk typically end in Dowell?
The last hard freeze (28°F) in Dowell typically lands around Mar 25, 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 15.
When is the first frost in Dowell?
The first hard freeze (28°F) in Dowell typically arrives around Nov 8, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 25, so the watching starts about Oct 9 — about 228 days after the spring freeze cleared.
How long is the growing season in Dowell?
Measured between 28°F hard freezes, Dowell sees about 228 frost-free days — roughly Mar 25 through Nov 8, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 15 to Oct 25, about 193 days.
Is the soil safe to grow vegetables in Dowell?
The federal record around Dowell shows 93 documented sites, mostly Underground Storage Tanks entries (65), the nearest Underground Storage Tanks record about 0.3 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 Dowell?
From about Oct 9 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 8 (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 8. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Dowell's scale — its 7a band and its 228-day season. Your yard writes its own version of Dowell'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 Dowell’s own scale
6 of the readings below were taken at Dowell's own scale — its own ~228-day season between 28°F freezes, the 250 acres it covers and 93 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Dowell's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Dowell's own 28°F hard-freeze dates, about Mar 25 and Nov 8 and the ~228-day span between themNOAA 1991–2020 Climate Normals
- 93 documented contamination sites on the federal record near Dowell, the closest Underground Storage Tanks record about 0.3 miles out from the town centreFederal environmental registers
- Dowell's boundary and the 250 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~228-day seasonGrowable Ground crop-matching engine
- The ecoregion at Dowell'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 Dowell's 250 acres read through its county's SSURGO summaryfrom Jackson County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Jackson 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 Jackson County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Dowell's 250 acreswhy one lot differs from the next →
- Which side of Dowell you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 250 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.3 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 Dowell-wide figureread your own land →