What USDA hardiness zone is Harnett County, North Carolina?

Every ZIP code in Harnett County, North Carolina is USDA hardiness zone 8a, from the USDA 2023 Plant Hardiness Zone Map.

When is the last spring frost in Harnett County, North Carolina?

The median last spring freeze runs March 28 – April 10 across the 5 NOAA weather stations serving Harnett County, North Carolina, from NOAA 1991-2020 Climate Normals. Half of years freeze later than the median.

North Carolina

Planting zones in Harnett County, North Carolina

Every ZIP code in this county is USDA zone 8a — so unlike most of the places people look up, there is one right answer here and it holds wherever you are in the county.

USDA zone 8a The same in all 11 ZIP codes

ZIP codes 11 11 have a NOAA station within range

Weather stations 5 NOAA 1991–2020 normals, across 595 sq mi

Your ZIP code

Get the exact answer for your address

Everything above describes Harnett County, North Carolina as a whole. Hardiness zones and freeze dates are published per ZIP code, so yours is exact — enter it and this page will tell you your zone, which NOAA station it comes from and how far away that station is.

Harnett County does not have one planting answer

Its own weather stations disagree about 12 of the 32 crops in this table right now, so any single list would be wrong for part of the county. That is not a gap in the data — it is what the data says.

Shortest season: 203 days
SANFORD 8 NE, NC US (USC00317656)
Longest season: 227 days
FAYETTEVILLE (PWC), NC US (USC00313017)

24 days of growing season separate those two stations, and both serve ZIP codes in Harnett County. The ZIP lookup above answers for one address instead of averaging a place that has no average.

Why the hardiness zone does not settle this

A USDA zone is a winter-minimum statistic. It was never a growing-season one, and it does not behave like one: within a single zone the growing season runs a median 54 days wider at the 10th–90th percentile, and annual growing degree days vary by 2.02×.

The zones also overlap rather than stack — 30% of zone 6b freezes before the median zone 6a station. The zone tells you what survives your winter; the station tells you what finishes before your autumn.

The whole dataset behind that →

All 5 stations agreeAt least one station

Every one of the 5 NOAA stations serving this county counts April 10 – October 30 as growing season (203 days). Widening to any single station gives March 28 – November 10 (227 days).

That is a 24-day difference inside one county — which is why this page gives ranges rather than a single planting date. The ZIP lookup above resolves it to one station.

Your freeze dates

Last spring freeze March 28 – April 10

First fall freeze October 30 – November 10

Across the 5 NOAA stations serving this county. These are medians — half of years freeze later than the date shown — so treat the later end of each range as the cautious one.

The growing season runs 203–227 days depending which station you are nearest, as published by NOAA rather than computed from the dates above. Summer highs average 88.3–90.2 °F in June–August. That is past the point where tomato and pepper pollen fails and cool-season greens bolt, so in this county heat decides as much as frost does. Summer rain over the same months runs 14.1–16.4" across those 5 stations, against the rough inch a week — about 13 inches over the same 92 days — that a vegetable garden is usually reckoned to want. At the middle station that is covered, so watering in Harnett County is for the gaps between storms rather than the whole season. The inches are NOAA's published normals; the inch a week is a rule of thumb, and it takes no account of a 89 °F summer afternoon drying the soil faster than a cool one.

Every ZIP code in Harnett County

Zones are published per ZIP code, not per county, so this is the exact answer rather than the county's average. The station column is the nearest one to that ZIP code's centroid and how far away it is — the same figure the tools use, shown here so you can see which ZIP codes are well covered and which are reaching.

ZIP code	USDA zone	Nearest NOAA station	Distance
27501	8a	Lillington, NC	15.0 km
27505	8a	Sanford 8 NE, NC	14.9 km
27506	8a	Lillington, NC	7.3 km
27521	8a	Dunn 4 NW, NC	10.2 km
27526	8a	Lillington, NC	15.3 km
27546	8a	Lillington, NC	4.5 km
28323	8a	Lillington, NC	10.3 km
28326	8a	Carthage Wtp, NC	23.9 km
28339	8a	Dunn 4 NW, NC	4.4 km
28368	8a	Sanford 8 NE, NC	19.4 km
28390	8a	Fayetteville (Pwc), NC	19.9 km

ZIP-code positions are area centroids, so a large rural ZIP code's listed distance is measured from the middle of its area rather than from any particular address in it.

When to start seeds in Harnett County

Every date below is anchored on the last spring freeze at each station and reported as a range across all 5 of them, because no one station speaks for the county.

Crop	Job	When	Offset
🧅 Green Onions	Start indoors	January 31 – February 13	8 wk before
🌶️ Peppers	Start indoors	January 31 – February 13	8 wk before
🥦 Broccoli	Start indoors	February 14 – February 27	6 wk before
🥬 Cabbage	Start indoors	February 14 – February 27	6 wk before
🥬 Collards	Start indoors	February 14 – February 27	6 wk before
🥬 Kale	Start indoors	February 14 – February 27	6 wk before
🥬 Leaf Lettuce	Start indoors	February 14 – February 27	6 wk before
🫛 Peas	Direct sow	February 14 – February 27	6 wk before
🥬 Spinach	Direct sow	February 14 – February 27	6 wk before
🍠 Sweet Potato	Start indoors	February 14 – February 27	6 wk before
🍅 Tomatoes	Start indoors	February 14 – February 27	6 wk before
🥬 Bok Choy	Start indoors	February 21 – March 6	5 wk before
🥬 Kohlrabi	Start indoors	February 21 – March 6	5 wk before
🥬 Swiss Chard	Start indoors	February 21 – March 6	5 wk before
🥬 Arugula	Direct sow	February 28 – March 13	4 wk before
🥬 Baby Salad Greens	Direct sow	February 28 – March 13	4 wk before
🥕 Beets	Direct sow	February 28 – March 13	4 wk before
🧅 Green Onions	Direct sow	February 28 – March 13	4 wk before
🥬 Mustard Greens	Direct sow	February 28 – March 13	4 wk before
🌶️ Okra	Start indoors	February 28 – March 13	4 wk before
🌱 Radishes	Direct sow	February 28 – March 13	4 wk before
🥔 Turnips	Direct sow	February 28 – March 13	4 wk before
🥬 Cabbage	Set out	March 7 – March 20	3 wk before
🥕 Carrots	Direct sow	March 7 – March 20	3 wk before
🥬 Collards	Direct sow	March 7 – March 20	3 wk before
🥬 Collards	Set out	March 7 – March 20	3 wk before
🥒 Cucumbers	Start indoors	March 7 – March 20	3 wk before
🧅 Green Onions	Set out	March 7 – March 20	3 wk before
🥬 Kale	Direct sow	March 7 – March 20	3 wk before
🥬 Kale	Set out	March 7 – March 20	3 wk before
🥬 Kohlrabi	Direct sow	March 7 – March 20	3 wk before
🥬 Kohlrabi	Set out	March 7 – March 20	3 wk before
🥬 Leaf Lettuce	Direct sow	March 7 – March 20	3 wk before
🎃 Pumpkins	Start indoors	March 7 – March 20	3 wk before
🎃 Summer Squash	Start indoors	March 7 – March 20	3 wk before
🎃 Winter Squash	Start indoors	March 7 – March 20	3 wk before
🥒 Zucchini	Start indoors	March 7 – March 20	3 wk before
🥬 Bok Choy	Direct sow	March 14 – March 27	2 wk before
🥬 Bok Choy	Set out	March 14 – March 27	2 wk before
🥦 Broccoli	Set out	March 14 – March 27	2 wk before
🌿 Cilantro	Direct sow	March 14 – March 27	2 wk before
🥬 Leaf Lettuce	Set out	March 14 – March 27	2 wk before
🥬 Swiss Chard	Direct sow	March 14 – March 27	2 wk before
🥬 Swiss Chard	Set out	March 14 – March 27	2 wk before
🌿 Dill	Direct sow	March 21 – April 3	1 wk before
🫘 Bush Beans	Direct sow	April 4 – April 17	1 wk after
🥒 Cucumbers	Set out	April 4 – April 17	1 wk after
🎃 Pumpkins	Direct sow	April 4 – April 17	1 wk after
🎃 Pumpkins	Set out	April 4 – April 17	1 wk after
🎃 Summer Squash	Direct sow	April 4 – April 17	1 wk after
🎃 Summer Squash	Set out	April 4 – April 17	1 wk after
🌽 Sweet Corn	Direct sow	April 4 – April 17	1 wk after
🍅 Tomatoes	Set out	April 4 – April 17	1 wk after
🎃 Winter Squash	Direct sow	April 4 – April 17	1 wk after
🎃 Winter Squash	Set out	April 4 – April 17	1 wk after
🥒 Zucchini	Direct sow	April 4 – April 17	1 wk after
🥒 Zucchini	Set out	April 4 – April 17	1 wk after
🥒 Cucumbers	Direct sow	April 11 – April 24	2 wk after
🌶️ Okra	Direct sow	April 11 – April 24	2 wk after
🌶️ Okra	Set out	April 11 – April 24	2 wk after
🌶️ Peppers	Set out	April 11 – April 24	2 wk after
🫘 Southern Peas	Direct sow	April 11 – April 24	2 wk after
🍠 Sweet Potato	Set out	April 11 – April 24	2 wk after

Offsets are published guidance; the dates they land on are computed from measured NOAA normals. The seed-starting tool does this for your own ZIP code and counts the days.

What lives through a zone 8a winter

Of 74 perennial edibles, 57 come through a zone 8a winter — and 8 fail here for being too warm rather than too cold, needing more winter chill than this county gets or more heat than they tolerate. Among the ones that work: Apple, Aronia, Elderberry, Summer Raspberry, Asparagus, Horseradish, Rhubarb, Sunchoke.

Hardiness ranges are a judgement, published by growers rather than measured; the zone they are compared against is measured. On a warm-end verdict, check with your local extension service — a coastal zone 8 and an inland zone 8 are not the same summer.

Cautious — shortens the seasonMedian across stationsOptimistic

Last spring freeze: Plan to April 25 to be careful. Median March 28 – April 10 across 5 stations; March 9 is the optimistic end.
First fall freeze: Plan to October 15 to be careful. Median October 30 – November 10 across 5 stations; November 29 is the optimistic end.

NOAA publishes these as probabilities, not averages — the middle figure is a median, so half of years fall either side of it. The cautious end is the 10% tail: in roughly nine years in ten the freeze falls on the safe side of it.

The 5 stations behind these numbers

All 5 NOAA stations whose normals this page quotes, spanning about 53 km north to south. Every one is named with its identifier in the station list below — this page does not single one out, because no one station speaks for a whole county.

A relative sketch, not a map with a projection: longitude is adjusted for latitude so the shape is not stretched, and there is no basemap. For the one station nearest a specific address, with its real distance, use the ZIP lookup above.

These are the stations this county's ZIP codes actually cite as nearest — not a claim that each one sits inside its boundary, since a rural ZIP legitimately reaches over it. Every figure above comes from them, and each is named so you can check it.

Station	NOAA ID	Last spring freeze	First fall freeze	Season
Carthage Wtp, NC	USC00311515	April 1	November 5	219 days
Dunn 4 NW, NC	USC00312500	March 28	November 7	226 days
Fayetteville (Pwc), NC	USC00313017	March 30	November 10	227 days
Lillington, NC	USC00314987	March 30	November 6	223 days
Sanford 8 NE, NC	USC00317656	April 10	October 30	203 days

These are medians, not averages — NOAA publishes freeze dates as a probability distribution, and half of years freeze later than the date shown.

Your own ZIP

Work out your own dates

This page describes a whole county. Every tool below answers for one ZIP code, which is the grain the underlying data is published at.

Other places to compare

Harnett County sits in North Carolina. That page carries the whole state's zone spread, its metro areas, and every other county in it with a page here.

More of North Carolina

Counties with the same zones — 8a

Matched on the exact zone set, not a dominant zone, so the winter answer on these pages really is the same one as here.

Gear

If you want to act on this

Each link opens an Amazon search rather than a product we picked. We have not tested these and do not rank them — the search is the honest version, and you choose.

Row cover and frost clothThe season here closes at the first fall freeze dated above — a cover buys back some of those days at the end.
MulchFor the perennials nearest their cold limit in zone 8a, where an insulated crown is what decides whether they come back.

As an Amazon Associate we earn from qualifying purchases. That costs you nothing extra, and it buys no influence over anything on this site: the dates come from NOAA normals and the zones from the USDA, and no product affects either.

Sources

Where these numbers come from

Hardiness zones are the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. Freeze dates and growing-season lengths are NOAA 1991–2020 Climate Normals, taken per station and cited above by name and NOAA ID.

County boundaries come from the Census ZCTA-to-county relation, which is what places each ZIP code — and which treats parishes, boroughs and census areas as county equivalents. No station is chosen to represent this county: every range above is taken across all of them and the count is stated, because picking one would be a judgement dressed as a measurement.