Saybrook, Illinois, sits in USDA hardiness zones 6a-7b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Reliable performers under these conditions include sweet corn, tomato, pumpkin, and apple; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Saybrook, 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 Saybrook 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.
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Quick Facts
USDA Zones
6a-7b
Last Hard Freeze (28°F)
Mar 24
Town normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Nov 16
Town normal — light frosts arrive a few weeks earlier
Town Area
513 acres
Hardiness Zone Range
Zone maps are averages across Saybrook. 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.
What Grows in Saybrook
Plants matched to Saybrook's USDA zones 6a-7b — each links to its full growing profile.
Is it too late to plant in Saybrook?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Feb 24; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 24 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 16 — 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.
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
88
within ~10 miles of Saybrook
Risk Level
Moderate
Highest-severity
2 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Saybrook
Severity Distribution
within ~10 miles of Saybrook
Highest-Severity Sites
Know Before You Grow
- •Underground tanks can leak petroleum products. Soil testing near former gas stations is recommended.
- •Raised beds with imported soil can reduce exposure risk near brownfield sites.
- •Test well water for nitrates if you rely on a private well. Levels above 10 mg/L require treatment.
Check your specific parcel in Saybrook
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:
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
Saybrook Average
- ●USDA Zones 6a-7b
- ●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
Read your specific parcel in Saybrook
Pull a site-specific report for your exact address in Saybrook, Illinois — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your exact spot that zone averages miss:
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 Saybrook, Illinois
- USDA Hardiness Zones: 6a-7b (USDA PHZM 2023)
- Last Hard Freeze (28°F): Mar 24 (town normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Nov 16 (town normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~237 (town normal, NOAA 1991–2020 Climate Normals)
- Land Area: 513 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 Saybrook, Illinois?
Saybrook sits in USDA hardiness zones 6a-7b, 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 Saybrook?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Feb 24; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 24 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 16 — 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.
When does frost risk typically end in Saybrook?
The last hard freeze (28°F) in Saybrook typically lands around Mar 24, 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 Saybrook?
The first hard freeze (28°F) in Saybrook typically arrives around Nov 16, 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 Saybrook?
Saybrook's zones 6a-7b 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 Saybrook, really?
Officially, Saybrook sits in USDA zones 6a-7b (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 Saybrook?
The federal record around Saybrook shows 88 documented sites — 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 Saybrook?
As the season closes around the first 28°F hard freeze near Nov 16 (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 Saybrook 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.