East Rocky Hill, New Jersey, sits in USDA hardiness zone 7a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Reliable performers under these conditions include cabbage, hazelnut, california poppy, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in East Rocky Hill, 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 East Rocky Hill 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 East Rocky Hill — soil, climate, flood, and parcel records. How we handle your address.
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East Rocky Hill — the short answer
East Rocky Hill, New Jersey: USDA zone 7a, about 216 days between hard freezes, across 3K acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 4
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~216
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 3K 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 East Rocky Hill's average, not your lot's — a low corner or a tree line moves it. Against East Rocky Hill's 216-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in East Rocky Hill
Each reading below is measured for East Rocky Hill itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredEast Rocky Hill runs about 216 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
MeasuredEast Rocky Hill 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 East Rocky Hill is in
East Rocky Hill sits in the Northern Piedmont — EPA Level III, inside the wider Eastern Temperate Forests. That is read at East Rocky Hill's own centroid rather than borrowed from Somerset County.
What Grows in East Rocky Hill
Every plant below cleared East Rocky Hill's own zone 7a and its 216-day season. Each card opens that plant's New Jersey profile. How we score.
Is it too late to plant in East Rocky Hill?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 5; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 2 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 4 — 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.
Documented around East Rocky Hill
Spotted lanternfly documented 3 miles from East Rocky Hill, first recorded 2019. What to watch for.
What's on the federal record near East Rocky Hill
Closest first, within ~10 miles of East Rocky Hill. Listing isn't leaking, and distance isn't exposure.
- 350103-- DomNitrate · 0.7 mi
- Griggstown MineMining · 0.8 mi
- Griggstown Franklin MineMining · 0.9 mi
- HIGGINS FARMSuperfund · 1.0 mi
- Griggstown Copper MineMining · 1.2 mi
- MONTGOMERY TWP TREATMENT PLTUnderground Storage Tanks · 1.2 mi
- RIVERVIEW TRANSPORTATION INCUnderground Storage Tanks · 1.2 mi
- INGERSOLL-RAND RESEARCH INCUnderground Storage Tanks · 1.3 mi
- MONTGOMERY TOWNSHIP HOUSING DEVELOPMENTSuperfund · 1.5 mi
- PRINCETON GAMMA TECH INCUnderground Storage Tanks · 1.5 mi
- CHURCH & DWIGHT CO INC - ROCKY HILLBrownfields · 1.5 mi
- ENACHIP, INCBrownfields · 1.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from East Rocky Hill'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 East Rocky Hill.
Sources Checked
within ~10 miles of East Rocky Hill
Severity Distribution
within ~10 miles of East Rocky Hill
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around East Rocky Hill, Superfund runs higher than the national average — 45 sites within ~10 miles of East Rocky Hill. That's not a problem with your land — it's information about it.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in East Rocky Hill
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 East Rocky Hill average
Your land is one point inside East Rocky Hill
Everything above resolves to East Rocky Hill as a whole — one PHZM band and one 28°F frost record, read across 3K 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 East Rocky Hill Average
East Rocky Hill Average
- ●USDA Zones 7a, averaged across East Rocky Hill
- ●One soil character for all of East Rocky Hill
- ●Frost dates read at East Rocky Hill's scale: Apr 2 to Nov 4
YOUR Parcel
- ✓Your exact zone, not East Rocky Hill's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in East Rocky Hill
Pull a site-specific report for your exact address in East Rocky Hill, New Jersey — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that East Rocky Hill averages can't show:
We read public map data around East Rocky Hill — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the East Rocky Hill average
How we know this about East Rocky Hill
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 East Rocky Hill’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 East Rocky Hill
When does frost risk typically end in East Rocky Hill?
The last hard freeze (28°F) in East Rocky Hill typically lands around Apr 2, 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 23.
When is the first frost in East Rocky Hill?
The first hard freeze (28°F) in East Rocky Hill typically arrives around Nov 4, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 21, so the watching starts about Oct 5 — about 216 days after the spring freeze cleared.
How long is the growing season in East Rocky Hill?
Measured between 28°F hard freezes, East Rocky Hill sees about 216 frost-free days — roughly Apr 2 through Nov 4, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 23 to Oct 21, about 181 days.
Is the soil safe to grow vegetables in East Rocky Hill?
The federal record around East Rocky Hill runs heavier than most — 1,795 documented sites, mostly Underground Storage Tanks entries (784), the nearest Nitrate record about 0.7 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 East Rocky Hill?
From about Oct 5 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 4 (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 4. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at East Rocky Hill's scale — its 7a band and its 216-day season. Your yard writes its own version of East Rocky Hill'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 East Rocky Hill’s own scale
7 of the readings below were taken at East Rocky Hill's own scale — its own ~216-day season between 28°F freezes, the 2,667 acres it covers and 1,795 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- East Rocky Hill's own USDA hardiness band, zones 7aUSDA PHZM 2023
- East Rocky Hill's own 28°F hard-freeze dates, about Apr 2 and Nov 4 and the ~216-day span between themNOAA 1991–2020 Climate Normals
- 1,795 documented contamination sites on the federal record near East Rocky Hill, the closest Nitrate record about 0.7 miles out from the town centreFederal environmental registers
- East Rocky Hill's boundary and the 2,667 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~216-day seasonGrowable Ground crop-matching engine
- The ecoregion at East Rocky Hill's own centroid, the Northern PiedmontUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of East Rocky Hilllydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so East Rocky Hill's 2,667 acres read through its county's SSURGO summaryfrom Somerset County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Somerset County
- The growing challenges every New Jersey grower plans around — written at state scale, so they stay on the state guidefrom New Jersey
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Somerset County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among East Rocky Hill's 2,667 acreswhy one lot differs from the next →
- Which side of East Rocky Hill you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,667 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.7 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 East Rocky Hill-wide figureread your own land →
More in New Jersey
Wider growing context
What grows across New JerseyEast Rocky Hill sits outside our named growing regions, so New Jersey as a whole is its closest context here.
Nearby growing guides