Cedar Knolls, New Jersey, sits in USDA hardiness zone 7a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Expect cabbage, hazelnut, california poppy, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Cedar Knolls, 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 Cedar Knolls 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 Cedar Knolls — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Cedar Knolls — the short answer
Cedar Knolls, New Jersey: USDA zone 7a, about 211 days between hard freezes, across 1K acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 4
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 1
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~211
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 Cedar Knolls's average, not your lot's — a low corner or a tree line moves it. Against Cedar Knolls's 211-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Cedar Knolls
Each reading below is measured for Cedar Knolls itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCedar Knolls runs about 211 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
MeasuredCedar Knolls 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 Cedar Knolls is in
Cedar Knolls sits in the Northern Piedmont — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Cedar Knolls's own centroid, and it is not what its county reads: Morris County is mostly Northeastern Highlands. The wider page above you is answering a different question about different ground.
What Grows in Cedar Knolls
Every plant below cleared Cedar Knolls's own zone 7a and its 211-day season. Each card opens that plant's New Jersey profile. How we score.
Is it too late to plant in Cedar Knolls?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 7; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 4 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 1 — 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 Cedar Knolls
Spotted lanternfly documented 1 miles from Cedar Knolls, first recorded 2019. What to watch for.
What's on the federal record near Cedar Knolls
Closest first, within ~10 miles of Cedar Knolls. Listing isn't leaking, and distance isn't exposure.
- CEDAR CONCRETE & CURB INCUnderground Storage Tanks · 1900 ft
- KONNER KEVAH INCUnderground Storage Tanks · 1900 ft
- JD CONSTRUCTIONUnderground Storage Tanks · 1900 ft
- MORRIS TECHNICAL CENTERBrownfields · 2200 ft
- ZIMMER TRABECULAR METAL TECHNOLOGY INCToxics Release Inventory · 2300 ft
- RIDGEDALE CORPORATE PARK LOT #5Underground Storage Tanks · 2500 ft
- COLLOID CHEMICAL INCToxics Release Inventory · 0.5 mi
- NORTHERN NJUnderground Storage Tanks · 0.5 mi
- SOUTHEAST MORRIS CNTY MUABrownfields · 0.5 mi
- PMG 8149Underground Storage Tanks · 0.5 mi
- MARK LITHOGRAPHERSBrownfields · 0.5 mi
- STANDARD ROOFINGS INCORPORATEDUnderground Storage Tanks · 0.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Cedar Knolls'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 Cedar Knolls.
Sources Checked
within ~10 miles of Cedar Knolls
Severity Distribution
within ~10 miles of Cedar Knolls
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Cedar Knolls, two things run higher than the national average within ~10 miles of Cedar Knolls — Superfund (81 sites) and PFAS (24 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Superfund: Superfund sites represent the most severe contamination in the federal system.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Cedar Knolls
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 Cedar Knolls average
Your land is one point inside Cedar Knolls
Everything above resolves to Cedar Knolls as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Cedar Knolls Average
Cedar Knolls Average
- ●USDA Zones 7a, averaged across Cedar Knolls
- ●One soil character for all of Cedar Knolls
- ●Frost dates read at Cedar Knolls's scale: Apr 4 to Nov 1
YOUR Parcel
- ✓Your exact zone, not Cedar Knolls's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Cedar Knolls
Pull a site-specific report for your exact address in Cedar Knolls, New Jersey — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Cedar Knolls averages can't show:
We read public map data around Cedar Knolls — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Cedar Knolls average
How we know this about Cedar Knolls
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 Cedar Knolls’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 Cedar Knolls
When does frost risk typically end in Cedar Knolls?
The last hard freeze (28°F) in Cedar Knolls typically lands around Apr 4, 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 25.
When is the first frost in Cedar Knolls?
The first hard freeze (28°F) in Cedar Knolls typically arrives around Nov 1, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 18, so the watching starts about Oct 2 — about 211 days after the spring freeze cleared.
How long is the growing season in Cedar Knolls?
Measured between 28°F hard freezes, Cedar Knolls sees about 211 frost-free days — roughly Apr 4 through Nov 1, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 25 to Oct 18, about 176 days.
Is the soil safe to grow vegetables in Cedar Knolls?
The federal record around Cedar Knolls runs heavier than most — 2,626 documented sites, mostly Underground Storage Tanks entries (1,465), the nearest Underground Storage Tanks record about 0.4 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 Cedar Knolls?
From about Oct 2 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 1 (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 1. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Cedar Knolls's scale — its 7a band and its 211-day season. Your yard writes its own version of Cedar Knolls'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 Cedar Knolls’s own scale
7 of the readings below were taken at Cedar Knolls's own scale — its own ~211-day season between 28°F freezes, the 1,316 acres it covers and 2,626 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Cedar Knolls's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Cedar Knolls's own 28°F hard-freeze dates, about Apr 4 and Nov 1 and the ~211-day span between themNOAA 1991–2020 Climate Normals
- 2,626 documented contamination sites on the federal record near Cedar Knolls, the closest Underground Storage Tanks record about 0.4 miles out from the town centreFederal environmental registers
- Cedar Knolls's boundary and the 1,316 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~211-day seasonGrowable Ground crop-matching engine
- Cedar Knolls sits in the Northern Piedmont — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Cedar Knollslydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Cedar Knolls's 1,316 acres read through its county's SSURGO summaryfrom Morris County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Morris 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 Morris County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Cedar Knolls's 1,316 acreswhy one lot differs from the next →
- Which side of Cedar Knolls you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,316 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.4 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 Cedar Knolls-wide figureread your own land →