Underhill Flats, Vermont, sits in USDA hardiness zones 4a-5b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Growers here do well with sugar maple, apple, garlic, and blueberry — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Underhill Flats, 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 Underhill Flats 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
4a-5b
Last Hard Freeze (28°F)
Apr 17
Town normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Nov 6
Town normal — light frosts arrive a few weeks earlier
Town Area
479 acres
Hardiness Zone Range
Zone maps are averages across Underhill Flats. 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 Underhill Flats
Plants matched to Underhill Flats's USDA zones 4a-5b — each links to its full growing profile.





Is it too late to plant in Underhill Flats?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 20; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 17 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 6 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.

Growing Challenges in Vermont
What an experienced grower plans around here — each one has a move.

Short growing season (100-130 frost-free days)
Indoor starts, fast varieties, and a cold frame on each shoulder — the Vermont formula for making 110 days feel like 150.

Rocky soils throughout the Green Mountains
Raised beds spare you the stone harvest — build up over cleared ground and plant the same weekend.

Heavy clay in the Champlain Valley
Champlain clay holds spring water late — raised or mounded beds dry out and warm up weeks earlier for planting.
For cultivar selection, pest pressure, and planting-time guidance specific to Vermont, the UVM Extension is the authoritative local source.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
Sources Checked
within ~10 miles of Underhill Flats
Severity Distribution
within ~10 miles of Underhill Flats
Highest-Severity Sites

A note from Gnorman
What an experienced grower watches for around here
In and around Underhill Flats, Brownfields runs higher than the national average — 207 sites nearby. That's not a problem with your land — it's information about it.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in Underhill Flats
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
Underhill Flats Average
- ●USDA Zones 4a-5b
- ●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 Underhill Flats
Pull a site-specific report for your exact address in Underhill Flats, Vermont — 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 Underhill Flats, Vermont
- USDA Hardiness Zones: 4a-5b (USDA PHZM 2023)
- Last Hard Freeze (28°F): Apr 17 (town normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Nov 6 (town normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~203 (town normal, NOAA 1991–2020 Climate Normals)
- Land Area: 479 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 Underhill Flats, Vermont?
Underhill Flats sits in USDA hardiness zones 4a-5b, 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 Underhill Flats?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 20; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 17 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 6 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
When does frost risk typically end in Underhill Flats?
The last hard freeze (28°F) in Underhill Flats typically lands around Apr 17, 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 Underhill Flats?
The first hard freeze (28°F) in Underhill Flats typically arrives around Nov 6, 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 Underhill Flats?
Underhill Flats's zones 4a-5b support a wide range — strong performers include Sugar Maple, Apple, Garlic, Blueberry, and Kale. 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 Underhill Flats, really?
Officially, Underhill Flats sits in USDA zones 4a-5b (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 Underhill Flats?
The federal record around Underhill Flats runs heavier than most — 385 documented sites — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
How do I protect my plants from frost in Underhill Flats?
As the season closes around the first 28°F hard freeze near Nov 6 (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 Underhill Flats 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.
