Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 28756 — Mill Spring, NC

ZIP code 28756 (Mill Spring, Polk County) is in USDA zone 8a: the coldest winter night averages 10 to 15 °F. The median last spring frost is April 5 and the first fall frost October 30.

Where ZIP 28756 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone8a10 to 15 °F

Coldest night−12.2 to −9.4 °C

Last frostApr 5

First frostOct 30

2012 zone7b

Was 7b on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 8a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Mill Spring, NC…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Mill Spring, NC

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostApril 5median — 50% chance of a later frost

Safe for tender plantsApril 20only 10% chance of frost after

First fall frostOctober 30median — 10% chance by Oct 18

Growing season207 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 25 and returns around November 10.

From the NOAA station Lake Lure 2, NC — 4 miles away, elevation 1,040 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 28756

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 22 – Mar 8

SpinachSow outdoors · Feb 22 – Mar 15

Broccoli, cabbageStart indoors · Jan 25 – Feb 8

Broccoli, cabbageTransplant · Mar 15 – Mar 29

Onion setsPlant outdoors · Mar 8 – Mar 22

PotatoesPlant outdoors · Mar 15 – Mar 29

LettuceSow outdoors · Mar 8 – Mar 22

Carrots, beetsSow outdoors · Mar 15 – Mar 29

TomatoesStart indoors · Feb 8 – Feb 22

TomatoesTransplant · Apr 12 – Apr 26

Peppers, eggplantStart indoors · Jan 25 – Feb 8

Peppers, eggplantTransplant · Apr 19 – May 3

BeansSow outdoors · Apr 12 – Apr 26

Sweet cornSow outdoors · Apr 12 – Apr 26

Cucumbers, squashSow outdoors · Apr 12 – Apr 26

Fall lettuce, spinachSow outdoors · Sep 4 – Sep 18

GarlicPlant cloves · Oct 16 – Nov 20

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 5) and first fall frost (Oct 30) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 28756 came on Feb 21 — about the same time as the 1991–2020 average (Feb 20).

average
Feb 202026
Feb 21

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 8a in North Carolina

619 plants native to the lower 48 states, recorded in North Carolina, and rated by the USDA to survive 10 °F or colder — the bottom of zone 8a. Each links to its USDA PLANTS profile.

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Mill Spring, NC.

Soil in Mill Spring, NC

The soil mapped at the center of ZIP 28756 is Pacolet — sandy clay loam, well drained.

TextureSandy clay loamholds water and nutrients; slow to drain and warm up

pH6.2slightly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter0.75%low — add compost

Hydrologic groupBwater soaks in moderately

Farmland classFarmland of statewide importanceUSDA classification

Map unit: Pacolet sandy clay loam, 8 to 15 percent slopes, moderately eroded.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 28756; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mill Spring, NC

Summer high88 °Faverage high, July

Winter low28 °Faverage low, January

Hot days45days a year at 90 °F or more

Freezing nights83nights a year at 32 °F or less

Growing degree days4,278base 50 °F — the season’s usable heat

Longest day14 h 33 mindaylight on June 21

Shortest day9 h 46 mindaylight on December 21

Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully

Precipitation60 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Lake Lure 2, NC (4 mi away); precipitation: Columbus 6.6 Nnw, NC (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

5 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

287207b

Chimney Rock, NC · 7 mi

287277b

Edneyville, NC · 8 mi

Hendersonville, NC · 9 mi

North Carolina planting zones →

Questions about 28756

What planting zone is ZIP code 28756?

ZIP code 28756 (Mill Spring, NC) is in USDA hardiness zone 8a on the 2023 map: the coldest night of an average winter reaches 10 to 15 °F (−12.2 to −9.4 °C).

When is the last frost in Mill Spring, NC?

The median last spring frost (32 °F) near 28756 is April 5; after April 20 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Lake Lure 2 station.

When is the first frost in Mill Spring, NC?

The median first fall frost near 28756 is October 30, giving a median frost-free growing season of 207 days.

When should I plant tomatoes in 28756?

Start tomato seeds indoors around Feb 8 – Feb 22 and set transplants outside around Apr 12 – Apr 26, one to three weeks after the median last frost.

How much rain and snow does 28756 get?

About 60 inches of precipitation a year (NOAA 1991–2020 normals, Columbus 6.6 Nnw station).

How hot do summers get in Mill Spring, NC?

The average high peaks at 88 °F in July, with about 45 days a year at 90 °F or more.

What kind of soil does 28756 have?

The USDA soil survey maps Pacolet at the center of ZIP 28756: sandy clay loam, well drained, pH about 6.2 (slightly acidic).

Did spring come early in Mill Spring, NC in 2026?

Spring leaf-out near 28756 came on Feb 21 in 2026, about the same as the 1991–2020 average (Feb 20), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mill Spring, NC?

Intermediate onions: the longest day near 28756 is 14 h 33 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 28756 change?

Yes. The 2012 USDA map put 28756 in zone 7b; the 2023 map puts it in zone 8a. The newer map uses 1991–2020 data and more weather stations.