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

Planting zone for Oak Ridge, TN

Oak Ridge, TN is in USDA zone 7b across its 2 ZIP codes. The median last spring frost is April 5 and the first fall frost November 1.

Oak Ridge on the zone map

Outlined: its 1 ZIP code areas · 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

ZIP codes2

Last frostApr 5

First frostNov 1

Growing season210 days

7b 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Oak Ridge, TN…

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 Oak Ridge, TN

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 19only 10% chance of frost after

First fall frostNovember 1median — 10% chance by Oct 19

Growing season210 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 23 and returns around November 11.

From the NOAA station Oak Ridge Atdd, TN, elevation 906 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 Oak Ridge

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 6 – Sep 20

GarlicPlant cloves · Oct 18 – Nov 22

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 5) and first fall frost (Nov 1) 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 37831 came on Feb 25 — 5 days earlier than the 1991–2020 average (Mar 2).

average
Mar 22026
Feb 25

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 Tennessee

566 plants native to the lower 48 states, recorded in Tennessee, 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 Oak Ridge, TN.

Soil in Oak Ridge, TN

The soil mapped at the center of ZIP 37831 is Montevallo — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer

pH4.3strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter69%high

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Montevallo channery silt loam, 20 to 35 percent slopes.

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 37831; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Oak Ridge, TN

Summer high89 °Faverage high, July

Winter low30 °Faverage low, January

Hot days44days a year at 90 °F or more

Freezing nights68nights a year at 32 °F or less

Growing degree days4,727base 50 °F — the season’s usable heat

Longest day14 h 37 mindaylight on June 21

Shortest day9 h 42 mindaylight on December 21

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

Precipitation57.5 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: Oak Ridge Asos, TN (6 mi away); precipitation: Oak Ridge 5.7 Ne, TN (6 mi away). Daylight is calculated from latitude.

ZIP codes in Oak Ridge

Tennessee planting zones →

Questions about Oak Ridge

What planting zone is Oak Ridge, TN?

Oak Ridge, TN is in USDA hardiness zone 7b on the 2023 map (7b: 5 to 10 °F).

When is the last frost in Oak Ridge, TN?

The median last spring frost is April 5 and the median first fall frost is November 1 (NOAA 1991–2020 normals, Oak Ridge Atdd station).

When can I plant a garden in Oak Ridge, TN?

Cool-season crops like peas and spinach go in around Feb 22 – Mar 15; tomatoes, peppers, beans and squash after about Apr 12, once frost risk has passed.

What kind of onions grow in Oak Ridge, TN?

Intermediate onions: the longest day is 14 h 37 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

How much rain and snow does Oak Ridge, TN get?

About 57.5 inches of precipitation a year (NOAA 1991–2020 normals).