Ayer, Massachusetts, sits in USDA hardiness zone 6a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
On paper, cabbage, hazelnut, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
You’re in Greater Boston
The state's dense urban core, where growing means raised beds, community plots, and back-lot kitchen gardens more than open field. A long, mild season for the region — but city soil is the thing to know before you dig.
Even in Ayer, 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 Ayer 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 Ayer — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Ayer — the short answer
Ayer, Massachusetts: USDA zone 6a, about 199 days between hard freezes, across 849 acres of town.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 10
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~199
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 849 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 6a is Ayer's average, not your lot's — a low corner or a tree line moves it. Against Ayer's 199-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Ayer
Each reading below is measured for Ayer itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredAyer runs about 199 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredAyer sits in USDA hardiness zone 6a.
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 Ayer is in
Ayer sits in the Northeastern Coastal Zone — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Ayer's own centroid rather than borrowed from Middlesex County.
What Grows in Ayer
Every plant below cleared Ayer's own zone 6a and its 199-day season. Each card opens that plant's Massachusetts profile. How we score.
Is it too late to plant in Ayer?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Mar 13; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 10 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 26 — long-season crops need about 90 days of runway, quick greens only 30. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
Documented around Ayer
Spotted lanternfly documented 9 miles from Ayer, first recorded 2020. What to watch for.
What's on the federal record near Ayer
Closest first, within ~10 miles of Ayer. Listing isn't leaking, and distance isn't exposure.
- DEPARTMENT OF THE ARMYUnderground Storage Tanks · 800 ft
- AYER MAIN POST OFFICEBrownfields · 1100 ft
- PINE TREE REALTYSuperfund · 1100 ft
- J AND A REALTY TRUST RESIDENTIAL PROPERTYBrownfields · 1200 ft
- MICRON PLASTICS INCBrownfields · 1500 ft
- INFO INCBrownfields · 1500 ft
- ARCHER'S MOBILBrownfields · 1500 ft
- MBTA KEOLIS AYER MAINTENANCE OF WAYBrownfields · 1500 ft
- Global Montello Group #1493Underground Storage Tanks · 1500 ft
- EXXON COMPANY USABrownfields · 1500 ft
- FORMER NU KAR FACILITYBrownfields · 1500 ft
- PMG #8626Underground Storage Tanks · 1700 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Ayer'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 Ayer.
Sources Checked
within ~10 miles of Ayer
Severity Distribution
within ~10 miles of Ayer
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Ayer, two things run higher than the national average within ~10 miles of Ayer — PFAS (13 sites) and Brownfields (738 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.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in Ayer
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 Ayer average
Your land is one point inside Ayer
Everything above resolves to Ayer as a whole — one PHZM band and one 28°F frost record, read across 849 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 Ayer Average
Ayer Average
- ●USDA Zones 6a, averaged across Ayer
- ●One soil character for all of Ayer
- ●Frost dates read at Ayer's scale: Apr 10 to Oct 26
YOUR Parcel
- ✓Your exact zone, not Ayer's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Ayer
Pull a site-specific report for your exact address in Ayer, Massachusetts — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Ayer averages can't show:
We read public map data around Ayer — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Ayer average
How we know this about Ayer
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 Ayer’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 Ayer
When does frost risk typically end in Ayer?
The last hard freeze (28°F) in Ayer typically lands around Apr 10, 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 May 1.
When is the first frost in Ayer?
The first hard freeze (28°F) in Ayer typically arrives around Oct 26, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 12, so the watching starts about Sep 26 — about 199 days after the spring freeze cleared.
How long is the growing season in Ayer?
Measured between 28°F hard freezes, Ayer sees about 199 frost-free days — roughly Apr 10 through Oct 26, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 1 to Oct 12, about 164 days.
Is the soil safe to grow vegetables in Ayer?
The federal record around Ayer runs heavier than most — 1,168 documented sites, mostly Brownfields entries (738), the nearest Underground Storage Tanks record about 0.2 miles out — 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 Ayer?
From about Sep 26 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 Oct 26 (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 Oct 26. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Ayer's scale — its 6a band and its 199-day season. Your yard writes its own version of Ayer'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 Ayer’s own scale
7 of the readings below were taken at Ayer's own scale — its own ~199-day season between 28°F freezes, the 849 acres it covers and 1,168 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Ayer's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Ayer's own 28°F hard-freeze dates, about Apr 10 and Oct 26 and the ~199-day span between themNOAA 1991–2020 Climate Normals
- 1,168 documented contamination sites on the federal record near Ayer, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Ayer's boundary and the 849 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~199-day seasonGrowable Ground crop-matching engine
- The ecoregion at Ayer's own centroid, the Northeastern Coastal ZoneUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Ayerlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Ayer's 849 acres read through its county's SSURGO summaryfrom Middlesex County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Middlesex County
- The growing challenges every Massachusetts grower plans around — written at state scale, so they stay on the state guidefrom Massachusetts
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Middlesex County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Ayer's 849 acreswhy one lot differs from the next →
- Which side of Ayer you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 849 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.2 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 Ayer-wide figureread your own land →
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