What Grows in Cobden, Illinois

USDA Zones 7a-8b · 781 acres

Cobden, Illinois, sits in USDA hardiness zones 7a-8b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.

On paper, sweet corn, tomato, pumpkin, and apple all suit these conditions — on the ground, soil, sun, and drainage make the final call.

Score your parcel · free

Even in Cobden, 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 Cobden lot. Enter your address and we'll score 1,112 plants against your land's actual soil, sun, and frost.

We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.

No card required · your full report in seconds

Quick Facts

USDA Zones

7a-8b

Last Hard Freeze (28°F)

Feb 28

Town normal — light frosts run a few weeks later

First Hard Freeze (28°F)

Dec 1

Town normal — light frosts arrive a few weeks earlier

Town Area

781 acres

Hardiness Zone Range

7a
8b
3a (Cold)13b (Hot)

Zone maps are averages across Cobden. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.

Soil varies lot by lot — soil types explained.

Is it too late to plant in Cobden?

Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Jan 31; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 28 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 1 — long-season crops need about 90 days of runway, quick greens only 30. Here the calendar nearly circles: cool-season crops take the winter shift, and the next window is always close.

Growing Challenges in Illinois

What an experienced grower plans around here — each one has a move.

Heavy clay soils in northern IL drain poorly

A raised bed solves the standing-water problem in a weekend; fall compost keeps improving the clay beneath it.

Extreme temperature swings between summer and winter

Wide swings reward truly hardy varieties and a deep mulch blanket — insulation smooths what the weather won't.

Japanese beetles are a major garden pest

Hand-pick into soapy water early and often, and skip the traps (they attract more than they catch) — extension IPM guides have the rest.

For cultivar selection, pest pressure, and planting-time guidance specific to Illinois, the University of Illinois Extension is the authoritative local source.

Environmental Intelligence

Understanding what's nearby helps you make informed decisions about where and how to grow.

Total Sites

98

within ~10 miles of Cobden

Risk Level

Elevated

Highest-severity

1 Toxics Release Inventory facility

Severity Distribution

within ~10 miles of Cobden

High5Moderate20Low73

Highest-Severity Sites

Alto Pass Lead Prospect No. 1
Mining Sites · Occurrence
Alto Pass Lead Prospect No. 1
Mining Sites · Occurrence
Alto Pass Lead Prospect No. 2
Mining Sites · Occurrence
Alto Pass Lead Prospect No. 2
Mining Sites · Occurrence
Anna
PFAS Sampling · PFAS Detected

A note from Gnorman

What an experienced grower watches for around here

In and around Cobden, two things run higher than the national average — PFAS (4 sites) and Underground Storage Tanks (69 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.

PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.

Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.

Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.

Use raised beds with imported soil — this eliminates the primary soil-contact pathway.

Free Report

Check your specific parcel in Cobden

Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,112 plant recommendations.

Three things about your exact spot that zone averages miss:

Your soil pHYour frost-free daysYour sun & shade

We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.

25+ data sources analyzed in seconds

Your Specific Parcel Matters

Cobden Average

  • USDA Zones 7a-8b
  • Generic soil type for the area
  • State-average frost dates

YOUR Parcel

  • Your exact hardiness zone
  • Your SSURGO soil type & pH
  • Your sun exposure, cast in 3D

See MY Growing Report

Free Report

Read your specific parcel in Cobden

Pull a site-specific report for your exact address in Cobden, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.

Three things about your exact spot that zone averages miss:

Your soil pHYour frost-free daysYour sun & shade

We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.

25+ data sources analyzed in seconds

Key Growing Facts for Cobden, Illinois

  • USDA Hardiness Zones: 7a-8b (USDA PHZM 2023)
  • Last Hard Freeze (28°F): Feb 28 (town normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
  • First Hard Freeze (28°F): Dec 1 (town normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
  • Days Between Hard Freezes: ~276 (town normal, NOAA 1991–2020 Climate Normals)
  • Land Area: 781 acres (US Census TIGER 2025)

Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. Boundaries: US Census TIGER/Line 2025.

Frequently Asked Questions

What hardiness zone is Cobden, Illinois?

Cobden sits in USDA hardiness zones 7a-8b, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.

Is it too late to plant in Cobden?

Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Jan 31; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 28 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 1 — long-season crops need about 90 days of runway, quick greens only 30. Here the calendar nearly circles: cool-season crops take the winter shift, and the next window is always close.

When does frost risk typically end in Cobden?

The last hard freeze (28°F) in Cobden typically lands around Feb 28, per NOAA 1991–2020 climate normals — an earlier marker than the light-frost dates many planting charts quote. That marks the hard freeze, not the last light frost — light frosts can still bite for a few more weeks, so tender transplants usually wait another 2–3 weeks.

When is the first frost in Cobden?

The first hard freeze (28°F) in Cobden typically arrives around Dec 1, per NOAA 1991–2020 climate normals — the point most tender summer crops finish. Lighter frosts usually reach a couple of weeks earlier, so watch the forecast from late summer on and harvest or cover tender plants before the first cold night.

What vegetables grow in Cobden?

Cobden's zones 7a-8b support a wide range — strong performers include Sweet Corn, Tomato, Pumpkin, Apple, and Coneflower. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.

Which hardiness zone is Cobden, really?

Officially, Cobden sits in USDA zones 7a-8b (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,112 plants against what's actually there.

Is the soil safe to grow vegetables in Cobden?

The federal record around Cobden is a meaningful one — 98 documented sites — 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 Cobden?

As the season closes around the first 28°F hard freeze near Dec 1 (NOAA 1991–2020 climate normals), a few moves buy time: cover tender plants with floating row cover or an old sheet on still, clear nights, water the soil the afternoon before a freeze so it holds warmth overnight, and harvest frost-tender crops like tomatoes, peppers, and basil before the first hard night. Hardy greens and root crops shrug off light frost and often sweeten after it, so leave them in.

Everything on this page is a Cobden average. Your yard writes its own version — we read soil, sun, drainage, and frost at your exact address. Try it for 14 days — no card required.