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

Planting zone for 28138 — Rockwell, NC

ZIP code 28138 (Rockwell, Rowan County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 1 and the first fall frost November 2.

Where ZIP 28138 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.

Zone7b5 to 10 °F

Coldest night−15 to −12.2 °C

Last frostApr 1

First frostNov 2

2012 zone7b

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 7b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Rockwell, 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 Rockwell, NC

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 1median — 50% chance of a later frost

Safe for tender plantsApril 16only 10% chance of frost after

First fall frostNovember 2median — 10% chance by Oct 21

Growing season215 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 20 and returns around November 13.

From the NOAA station Concord, NC — 11 miles away, elevation 699 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 28138

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 18 – Mar 4

SpinachSow outdoors · Feb 18 – Mar 11

Broccoli, cabbageStart indoors · Jan 21 – Feb 4

Broccoli, cabbageTransplant · Mar 11 – Mar 25

Onion setsPlant outdoors · Mar 4 – Mar 18

PotatoesPlant outdoors · Mar 11 – Mar 25

LettuceSow outdoors · Mar 4 – Mar 18

Carrots, beetsSow outdoors · Mar 11 – Mar 25

TomatoesStart indoors · Feb 4 – Feb 18

TomatoesTransplant · Apr 8 – Apr 22

Peppers, eggplantStart indoors · Jan 21 – Feb 4

Peppers, eggplantTransplant · Apr 15 – Apr 29

BeansSow outdoors · Apr 8 – Apr 22

Sweet cornSow outdoors · Apr 8 – Apr 22

Cucumbers, squashSow outdoors · Apr 8 – Apr 22

Fall lettuce, spinachSow outdoors · Sep 7 – Sep 21

GarlicPlant cloves · Oct 19 – Nov 23

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 1) and first fall frost (Nov 2) 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 28138 came on Feb 22 — about the same time as the 1991–2020 average (Feb 21).

average
Feb 212026
Feb 22

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 7b in North Carolina

596 plants native to the lower 48 states, recorded in North Carolina, and rated by the USDA to survive 5 °F or colder — the bottom of zone 7b. 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 Rockwell, NC.

Soil in Rockwell, NC

The soil mapped at the center of ZIP 28138 is Mecklenburg — clay loam, well drained.

TextureClay loamholds water and nutrients; slow to drain and warm up

pH6.5neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter0.75%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classprime farmlandUSDA classification

Map unit: Mecklenburg clay loam, 2 to 8 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 28138; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Rockwell, NC

Summer high92 °Faverage high, July

Winter low29 °Faverage low, January

Hot days61days a year at 90 °F or more

Freezing nights74nights a year at 32 °F or less

Growing degree days4,914base 50 °F — the season’s usable heat

Longest day14 h 34 mindaylight on June 21

Shortest day9 h 45 mindaylight on December 21

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

Precipitation46.4 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: Concord, NC (11 mi away); precipitation: Faith 0.3 Wnw, NC (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

280417b

Faith, NC · 5 mi

280727b

Granite Quarry, NC · 7 mi

Mount Pleasant, NC · 8 mi

280838a

Kannapolis, NC · 8 mi

281098a

Misenheimer, NC · 9 mi

281378a

Richfield, NC · 10 mi

North Carolina planting zones →

Questions about 28138

What planting zone is ZIP code 28138?

ZIP code 28138 (Rockwell, NC) is in USDA hardiness zone 7b on the 2023 map: the coldest night of an average winter reaches 5 to 10 °F (−15 to −12.2 °C).

When is the last frost in Rockwell, NC?

The median last spring frost (32 °F) near 28138 is April 1; after April 16 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Concord station.

When is the first frost in Rockwell, NC?

The median first fall frost near 28138 is November 2, giving a median frost-free growing season of 215 days.

When should I plant tomatoes in 28138?

Start tomato seeds indoors around Feb 4 – Feb 18 and set transplants outside around Apr 8 – Apr 22, one to three weeks after the median last frost.

How much rain and snow does 28138 get?

About 46.4 inches of precipitation a year (NOAA 1991–2020 normals, Faith 0.3 Wnw station).

How hot do summers get in Rockwell, NC?

The average high peaks at 92 °F in July, with about 61 days a year at 90 °F or more.

What kind of soil does 28138 have?

The USDA soil survey maps Mecklenburg at the center of ZIP 28138: clay loam, well drained, pH about 6.5 (neutral).

Did spring come early in Rockwell, NC in 2026?

Spring leaf-out near 28138 came on Feb 22 in 2026, about the same as the 1991–2020 average (Feb 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Rockwell, NC?

Intermediate onions: the longest day near 28138 is 14 h 34 min, so day-neutral types bulb best; long-day varieties may not bulb fully.