Onslow County, in North Carolina, sits in USDA hardiness zone 8a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Expect cabbage, fig, california poppy, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Onslow County lies within Tidewater & Chesapeake — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Onslow County holds more than one microclimate.
Soils and elevations shift across Onslow County, so your frost dates and drainage aren't the county average. 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 Onslow County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Onslow County — the short answer
Onslow County, North Carolina: USDA zone 8a, about 256 days between hard freezes, across 488K acres.
- USDA zone
- 8a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 14
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 25
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~256
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 488K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 8a is Onslow County's average, not your lot's — a low corner or a tree line moves it. Against Onslow County's 256-day season, see what your own ground reads.
Heat and winter chill in Onslow County
Across a year, Onslow County accumulates about 4,958 growing degree days above 50°F, about 568 more than the middle North Carolina county — ahead of 89 of North Carolina’s 100 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Winter banks about 1,385 hours below 45°F, 378 fewer than the North Carolina middle of 1,763. Chill is what tells a fruit tree its dormancy is over, and it is set by climate rather than by anything you can build.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Onslow County
Across Onslow County, the ground is predominantly Ultisols, where Baymeade, Croatan, and Muckalee are the most extensive named soil series. The soil is generally poorly drained with a loamy fine sand surface. Topsoil pH runs about 4.5–5.5, very strongly acidic. Rainfall drains through hydrologic group A/D soils.
Soil order
Ultisols
Drainage
Poorly drained
Prime farmland
14%
Hydric soils
49%
Soil still varies lot by lot — soil types explained.
How the ground varies across Onslow County
The USDA soil survey maps 24% of Onslow County as poorly drained — but another 69% drains differently: 23% well drained, 21% very poorly drained.
Baymeade is the most extensive named soil at 11% of mapped acres, then Croatan (7%) and Muckalee (7%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Onslow County
Each reading below is measured for Onslow County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Onslow County are poorly drained, in hydrologic group A/D — ground that sheds water slowly.
Beds can stay saturated for days after heavy rain, and the roots of most vegetables, berries, and fruit trees suffocate or rot in soil that never drains.
Raised beds or mounded rows lift roots above the wet zone; choose water-tolerant crops for the lowest spots.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Onslow County runs about pH 4.5–5.5, on the acidic side.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Season length
MeasuredOnslow County runs about 256 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
MeasuredOnslow County sits in USDA hardiness zone 8a.
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 Onslow County is in
Onslow County sits in the Middle Atlantic Coastal Plain — EPA Level III, inside the wider Eastern Temperate Forests. One consistent ecological setting across the whole county.
What Grows in Onslow County
We scored all 1,086 plants against Onslow County's own USDA zone 8a and its own 256-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's North Carolina profile.
Is it too late to plant in Onslow County?
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 Feb 14; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 14 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 25 — 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 Onslow County
Survey cells within 31 miles of Onslow County checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 43 miles off. What to watch for.
What gets applied to farmland in Onslow County
USGS estimates 42,547 lb of Glyphosate on Onslow County farmland in 2019, its largest by weight, ahead of Atrazine (19,542 lb) and Metolachlor & Metolachlor-s (15,995 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Onslow County — and how to grow with it.
We checked the federal record across Onslow County — 550 documented sites across 7 of the 9 source types we track.
The most significant on record: 2 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Onslow County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Onslow County
Closest first, across Onslow County. Listing isn't leaking, and distance isn't exposure.
- PAUL'S FOOD MARTUnderground Storage Tanks · 0.6 mi
- SCOTCHMAN 3187Underground Storage Tanks · 0.7 mi
- SPEEDWAY #7941Underground Storage Tanks · 0.7 mi
- USMC LEJEUNE--NEW RIVER AIR STPFAS · 1.3 mi
- ON-310 MAS 15 IN JACKSONVILLE, NCNitrate · 1.3 mi
- COASTAL DRY CLEANERSBrownfields · 1.5 mi
- WALGREENS #12133Brownfields · 1.6 mi
- VALUE XPRESS MARTUnderground Storage Tanks · 1.6 mi
- WHIZZ MART 1Underground Storage Tanks · 1.6 mi
- SCOTCHMAN 3054Underground Storage Tanks · 1.7 mi
- BEST MART #1Underground Storage Tanks · 1.8 mi
- PETTEWAY VARIETY STOREUnderground Storage Tanks · 1.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Onslow County'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 Onslow County.
Sources Checked
across Onslow County
Severity Distribution
across Onslow County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Onslow County, two things run higher than the national average across Onslow County — PFAS (5 sites) and Underground Storage Tanks (353 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Onslow County
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 Onslow County average
Your land is one point inside Onslow County
Everything above resolves to Onslow County as a whole — one PHZM band and one county frost record, read across 488K 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 county 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 county average.
Your Lot vs the Onslow County Average
Onslow County Average
- ●USDA Zones 8a, averaged across Onslow County
- ●One soil character for all of Onslow County
- ●Frost dates read at Onslow County's scale: Mar 14 to Nov 25
YOUR Parcel
- ✓Your exact zone, not Onslow County's 8a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Onslow County
Pull a site-specific report for your exact address in Onslow County, North Carolina — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Onslow County averages can't show:
We read public map data around Onslow County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Onslow County average
How we know this about Onslow County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Onslow County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Onslow County
When does frost risk typically end in Onslow County?
The last hard freeze (28°F) in Onslow County typically lands around Mar 14, 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 4.
How long is the growing season in Onslow County?
Measured between 28°F hard freezes, Onslow County sees about 256 frost-free days — roughly Mar 14 through Nov 25, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 4 to Nov 11, about 221 days.
Is the soil safe to grow vegetables in Onslow County?
The federal record around Onslow County is a meaningful one — 550 documented sites, mostly Underground Storage Tanks entries (353), the nearest Underground Storage Tanks record about 0.6 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
Everything above is measured at Onslow County's scale — its 8a band and its 256-day season. Your yard writes its own version of Onslow County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads North Carolina's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Onslow County’s own scale
8 of the readings below were taken at Onslow County's own scale — its own ~256-day span between 28°F freezes, the 3 most extensive soil series mapped here and 550 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Onslow County's own USDA hardiness band, zones 8aUSDA PHZM 2023
- Onslow County's own 28°F hard-freeze dates and its ~256-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Onslow CountyUSDA NRCS SSURGO
- 550 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record about 0.6 miles outFederal environmental registers
- Onslow County's boundary and the 487,734 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8a and a ~256-day seasonGrowable Ground crop-matching engine
- Onslow County sitting wholly inside the Middle Atlantic Coastal PlainUS EPA Level III Ecoregions
- Which agricultural compounds go onto Onslow County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every North Carolina grower plans around — written at state scale, so they stay on the state guidefrom North Carolina
What this page can’t tell you
- How the season shifts across Onslow County — the ~256 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Onslow County's 487,734 acreswhy one lot differs from the next →
- Which of those 550 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Onslow Countyread your own land →