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

Planting zone for 37912 — Knoxville, TN

ZIP code 37912 (Knoxville, Knox County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 11 and the first fall frost October 28.

Where ZIP 37912 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 11
First frostOct 28
2012 zone7a

Was 7a 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 7b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Knoxville, 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 Knoxville, TN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 11median — 50% chance of a later frost
Safe for tender plantsApril 29only 10% chance of frost after
First fall frostOctober 28median — 10% chance by Oct 13
Growing season198 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 31 and returns around November 6.

From the NOAA station Knoxville Exp Stn, TN — 8 miles away, elevation 830 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 37912

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 28 – Mar 14
SpinachSow outdoors · Feb 28 – Mar 21
Broccoli, cabbageStart indoors · Jan 31 – Feb 14
Broccoli, cabbageTransplant · Mar 21 – Apr 4
Onion setsPlant outdoors · Mar 14 – Mar 28
PotatoesPlant outdoors · Mar 21 – Apr 4
LettuceSow outdoors · Mar 14 – Mar 28
Carrots, beetsSow outdoors · Mar 21 – Apr 4
TomatoesStart indoors · Feb 14 – Feb 28
TomatoesTransplant · Apr 18 – May 2
Peppers, eggplantStart indoors · Jan 31 – Feb 14
Peppers, eggplantTransplant · Apr 25 – May 9
BeansSow outdoors · Apr 18 – May 2
Sweet cornSow outdoors · Apr 18 – May 2
Cucumbers, squashSow outdoors · Apr 18 – May 2
Fall lettuce, spinachSow outdoors · Sep 2 – Sep 16
GarlicPlant cloves · Oct 14 – Nov 18
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 11) and first fall frost (Oct 28) 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 37912 came on Feb 25 — 3 days earlier than the 1991–2020 average (Feb 28).

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.

Trees 82

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican chestnut115 ft · blooms early summer · high shade tolerance · to −33 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °F

Shrubs 116

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °FAllegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Falternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °FAmerican beautyberry6 ft · blooms early summer · medium shade tolerance · to −8 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican holly40 ft · blooms mid spring · low shade tolerance · to −20 °F

Wildflowers & perennials 184

American bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °FAmerican speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °FAmerican spongeplant0.5 ft · blooms mid spring · high shade tolerance · to −24 °F

Grasses 157

American cupscale3 ft · blooms early summer · high shade tolerance · to −18 °Fautumn bluegrass1.5 ft · blooms late spring · medium shade tolerance · to −8 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °Fbig bluestem6 ft · blooms summer · high shade tolerance · to −46 °Fbluejoint5 ft · blooms late spring · high shade tolerance · to −33 °F

Vines 14

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °FAmerican wisteria50 ft · blooms spring · low shade tolerance · to −3 °Fcatbird grape30 ft · blooms late spring · medium shade tolerance · to −13 °Fcupseed30 ft · blooms late spring · low shade tolerance · to −3 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium shade tolerance · to −23 °F

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 Knoxville, TN.

Soil in Knoxville, TN

The soil mapped at the center of ZIP 37912 is Dewey — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH5.5moderately acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Dewey-Udorthents-Urban land complex, 2 to 12 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 37912; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Knoxville, TN

Summer high88 °Faverage high, July
Winter low26 °Faverage low, January
Hot days36days a year at 90 °F or more
Freezing nights87nights a year at 32 °F or less
Growing degree days4,278base 50 °F — the season’s usable heat
Longest day14 h 36 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
Precipitation54.5 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 48 °F, low 26 °F 48°26° JanFebruary: average high 53 °F, low 29 °F 53°29° FebMarch: average high 61 °F, low 36 °F 61°36° MarApril: average high 71 °F, low 44 °F 71°44° AprMay: average high 79 °F, low 54 °F 79°54° MayJune: average high 86 °F, low 62 °F 86°62° JunJuly: average high 88 °F, low 66 °F 88°66° JulAugust: average high 88 °F, low 65 °F 88°65° AugSeptember: average high 83 °F, low 59 °F 83°59° SepOctober: average high 72 °F, low 46 °F 72°46° OctNovember: average high 61 °F, low 35 °F 61°35° NovDecember: average high 51 °F, low 30 °F 51°30° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 5.16 in precipitation 5.2 JanFebruary: 5.11 in precipitation 5.1 FebMarch: 5.07 in precipitation 5.1 MarApril: 5.01 in precipitation 5.0 AprMay: 4.42 in precipitation 4.4 MayJune: 4.30 in precipitation 4.3 JunJuly: 5.80 in precipitation 5.8 JulAugust: 3.42 in precipitation 3.4 AugSeptember: 3.70 in precipitation 3.7 SepOctober: 2.96 in precipitation 3.0 OctNovember: 3.93 in precipitation 3.9 NovDecember: 5.61 in precipitation 5.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Knoxville Exp Stn, TN (8 mi away); precipitation: Knoxville 5.7 Nnw, TN (3 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7b.

379277b
Knoxville, TN · 2 mi
379287b
Knoxville, TN · 2 mi
379337b
Knoxville, TN · 2 mi
379397b
Knoxville, TN · 2 mi
379407b
Knoxville, TN · 2 mi
379507b
Knoxville, TN · 2 mi
379977b
Knoxville, TN · 2 mi
379217b
Knoxville, TN · 2 mi

All 29 ZIP codes in Knoxville → · Tennessee planting zones →

Questions about 37912

What planting zone is ZIP code 37912?

ZIP code 37912 (Knoxville, TN) 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 Knoxville, TN?

The median last spring frost (32 °F) near 37912 is April 11; after April 29 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Knoxville Exp Stn station.

When is the first frost in Knoxville, TN?

The median first fall frost near 37912 is October 28, giving a median frost-free growing season of 198 days.

When should I plant tomatoes in 37912?

Start tomato seeds indoors around Feb 14 – Feb 28 and set transplants outside around Apr 18 – May 2, one to three weeks after the median last frost.

How much rain and snow does 37912 get?

About 54.5 inches of precipitation a year (NOAA 1991–2020 normals, Knoxville 5.7 Nnw station).

How hot do summers get in Knoxville, TN?

The average high peaks at 88 °F in July, with about 36 days a year at 90 °F or more.

What kind of soil does 37912 have?

The USDA soil survey maps Dewey at the center of ZIP 37912: silt loam, well drained, pH about 5.5 (moderately acidic).

Did spring come early in Knoxville, TN in 2026?

Spring leaf-out near 37912 came on Feb 25 in 2026, 3 days earlier than the 1991–2020 average (Feb 28), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Knoxville, TN?

Intermediate onions: the longest day near 37912 is 14 h 36 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 37912 change?

Yes. The 2012 USDA map put 37912 in zone 7a; the 2023 map puts it in zone 7b. The newer map uses 1991–2020 data and more weather stations.