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

Planting zone for 37341 — Harrison, TN

ZIP code 37341 (Harrison, Hamilton County) is in USDA zone 8a: the coldest winter night averages 10 to 15 °F. The median last spring frost is April 7 and the first fall frost October 29.

Where ZIP 37341 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 7

First frostOct 29

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 Harrison, 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 Harrison, TN

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 7median — 50% chance of a later frost

Safe for tender plantsApril 28only 10% chance of frost after

First fall frostOctober 29median — 10% chance by Oct 13

Growing season203 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 27 and returns around November 8.

From the NOAA station Soddy Daisy-Mowbray Mtn, TN — 11 miles away, elevation 1,700 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 37341

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 24 – Mar 10

SpinachSow outdoors · Feb 24 – Mar 17

Broccoli, cabbageStart indoors · Jan 27 – Feb 10

Broccoli, cabbageTransplant · Mar 17 – Mar 31

Onion setsPlant outdoors · Mar 10 – Mar 24

PotatoesPlant outdoors · Mar 17 – Mar 31

LettuceSow outdoors · Mar 10 – Mar 24

Carrots, beetsSow outdoors · Mar 17 – Mar 31

TomatoesStart indoors · Feb 10 – Feb 24

TomatoesTransplant · Apr 14 – Apr 28

Peppers, eggplantStart indoors · Jan 27 – Feb 10

Peppers, eggplantTransplant · Apr 21 – May 5

BeansSow outdoors · Apr 14 – Apr 28

Sweet cornSow outdoors · Apr 14 – Apr 28

Cucumbers, squashSow outdoors · Apr 14 – Apr 28

Fall lettuce, spinachSow outdoors · Sep 3 – Sep 17

GarlicPlant cloves · Oct 15 – Nov 19

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 7) and first fall frost (Oct 29) 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 37341 came on Feb 20 — about the same time as the 1991–2020 average (Feb 19).

average
Feb 192026
Feb 20

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 Tennessee

575 plants native to the lower 48 states, recorded in Tennessee, 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 Harrison, TN.

Soil in Harrison, TN

The soil mapped at the center of ZIP 37341 is Fullerton — gravelly silt loam, well drained.

TextureGravelly silt loama good balance for most vegetables

pH5.0strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.5%low — add compost

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Fullerton cherty silt loam, 25 to 40 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 37341; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Harrison, TN

Summer high88 °Faverage high, July

Winter low28 °Faverage low, January

Hot days17days a year at 90 °F or more

Freezing nights82nights a year at 32 °F or less

Growing degree days4,237base 50 °F — the season’s usable heat

Longest day14 h 32 mindaylight on June 21

Shortest day9 h 47 mindaylight on December 21

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

Precipitation60.1 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: Soddy Daisy-Mowbray Mtn, TN (11 mi away); precipitation: Ooltewah 6.7 Nne, TN (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

373638a

Ooltewah, TN · 7 mi

373847b

Soddy Daisy, TN · 8 mi

373797b

Soddy Daisy, TN · 8 mi

Birchwood, TN · 10 mi

374168a

Chattanooga, TN · 10 mi

Tennessee planting zones →

Questions about 37341

What planting zone is ZIP code 37341?

ZIP code 37341 (Harrison, TN) 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 Harrison, TN?

The median last spring frost (32 °F) near 37341 is April 7; after April 28 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Soddy Daisy-Mowbray Mtn station.

When is the first frost in Harrison, TN?

The median first fall frost near 37341 is October 29, giving a median frost-free growing season of 203 days.

When should I plant tomatoes in 37341?

Start tomato seeds indoors around Feb 10 – Feb 24 and set transplants outside around Apr 14 – Apr 28, one to three weeks after the median last frost.

How much rain and snow does 37341 get?

About 60.1 inches of precipitation a year (NOAA 1991–2020 normals, Ooltewah 6.7 Nne station).

How hot do summers get in Harrison, TN?

The average high peaks at 88 °F in July, with about 17 days a year at 90 °F or more.

What kind of soil does 37341 have?

The USDA soil survey maps Fullerton at the center of ZIP 37341: gravelly silt loam, well drained, pH about 5.0 (strongly acidic).

Did spring come early in Harrison, TN in 2026?

Spring leaf-out near 37341 came on Feb 20 in 2026, about the same as the 1991–2020 average (Feb 19), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Harrison, TN?

Intermediate onions: the longest day near 37341 is 14 h 32 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 37341 change?

Yes. The 2012 USDA map put 37341 in zone 7b; the 2023 map puts it in zone 8a. The newer map uses 1991–2020 data and more weather stations.