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

Planting zone for 37755 — Helenwood, TN

ZIP code 37755 (Helenwood, Scott County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 23 and the first fall frost October 18.

Where ZIP 37755 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.

Zone7a0 to 5 °F

Coldest night−17.8 to −15 °C

Last frostApr 23

First frostOct 18

2012 zone6b

Was 6b 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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Helenwood, 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 Helenwood, TN

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 23median — 50% chance of a later frost

Safe for tender plantsMay 12only 10% chance of frost after

First fall frostOctober 18median — 10% chance by Oct 5

Growing season177 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 7 and returns around October 27.

From the NOAA station Oneida, TN — 6 miles away, elevation 1,440 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 37755

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 12 – Mar 26

SpinachSow outdoors · Mar 12 – Apr 2

Broccoli, cabbageStart indoors · Feb 12 – Feb 26

Broccoli, cabbageTransplant · Apr 2 – Apr 16

Onion setsPlant outdoors · Mar 26 – Apr 9

PotatoesPlant outdoors · Apr 2 – Apr 16

LettuceSow outdoors · Mar 26 – Apr 9

Carrots, beetsSow outdoors · Apr 2 – Apr 16

TomatoesStart indoors · Feb 26 – Mar 12

TomatoesTransplant · Apr 30 – May 14

Peppers, eggplantStart indoors · Feb 12 – Feb 26

Peppers, eggplantTransplant · May 7 – May 21

BeansSow outdoors · Apr 30 – May 14

Sweet cornSow outdoors · Apr 30 – May 14

Cucumbers, squashSow outdoors · Apr 30 – May 14

Fall lettuce, spinachSow outdoors · Aug 23 – Sep 6

GarlicPlant cloves · Oct 4 – Nov 8

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 23) and first fall frost (Oct 18) 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 37755 came on Feb 25 — 9 days earlier than the 1991–2020 average (Mar 6).

average
Mar 62026
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 7a in Tennessee

560 plants native to the lower 48 states, recorded in Tennessee, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. 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 Helenwood, TN.

Soil in Helenwood, TN

The soil mapped at the center of ZIP 37755 is Allegheny — loam, well drained.

TextureLoama good balance for most vegetables

pH5.3strongly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2.5%moderate

Hydrologic groupBwater soaks in moderately

Farmland classprime farmlandUSDA classification

Map unit: Allegheny-Cotaco complex, occasionally flooded.

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 37755; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Helenwood, TN

Summer high85 °Faverage high, July

Winter low25 °Faverage low, January

Hot days15days a year at 90 °F or more

Freezing nights117nights a year at 32 °F or less

Growing degree days3,628base 50 °F — the season’s usable heat

Longest day14 h 39 mindaylight on June 21

Shortest day9 h 40 mindaylight on December 21

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

Precipitation58.1 inper year, rain and melted snow

Snowfall6 inper year; 2 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Oneida, TN (6 mi away); precipitation: Oneida, TN (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

Huntsville, TN · 11 mi

Sunbright, TN · 13 mi

Tennessee planting zones →

Questions about 37755

What planting zone is ZIP code 37755?

ZIP code 37755 (Helenwood, TN) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Helenwood, TN?

The median last spring frost (32 °F) near 37755 is April 23; after May 12 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Oneida station.

When is the first frost in Helenwood, TN?

The median first fall frost near 37755 is October 18, giving a median frost-free growing season of 177 days.

When should I plant tomatoes in 37755?

Start tomato seeds indoors around Feb 26 – Mar 12 and set transplants outside around Apr 30 – May 14, one to three weeks after the median last frost.

How much rain and snow does 37755 get?

About 58.1 inches of precipitation a year and 6 inches of snowfall (NOAA 1991–2020 normals, Oneida station).

How hot do summers get in Helenwood, TN?

The average high peaks at 85 °F in July, with about 15 days a year at 90 °F or more.

What kind of soil does 37755 have?

The USDA soil survey maps Allegheny at the center of ZIP 37755: loam, well drained, pH about 5.3 (strongly acidic).

Did spring come early in Helenwood, TN in 2026?

Spring leaf-out near 37755 came on Feb 25 in 2026, 9 days earlier than the 1991–2020 average (Mar 6), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Helenwood, TN?

Intermediate onions: the longest day near 37755 is 14 h 39 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 37755 change?

Yes. The 2012 USDA map put 37755 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.