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

Planting zone for 38391 — Denmark, TN

ZIP code 38391 (Denmark, Madison County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 5 and the first fall frost October 29.

Where ZIP 38391 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 5
First frostOct 29
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 Denmark, 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 Denmark, 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 21only 10% chance of frost after
First fall frostOctober 29median — 10% chance by Oct 16
Growing season207 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 25 and returns around November 7.

From the NOAA station Jackson Mckellar Airport, TN — 6 miles away, elevation 433 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 38391

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 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 5) 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 38391 came on Feb 18 — 3 days earlier than the 1991–2020 average (Feb 21).

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 Denmark, TN.

Soil in Denmark, TN

The soil mapped at the center of ZIP 38391 is Lexington — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH5.3strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1.25%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Lexington silt loam, 8 to 12 percent slopes, severely 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 38391; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Denmark, TN

Summer high90 °Faverage high, July
Winter low29 °Faverage low, January
Hot days58days a year at 90 °F or more
Freezing nights74nights a year at 32 °F or less
Growing degree days4,870base 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
Precipitation53.9 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 49 °F, low 29 °F 49°29° JanFebruary: average high 53 °F, low 33 °F 53°33° FebMarch: average high 62 °F, low 40 °F 62°40° MarApril: average high 72 °F, low 48 °F 72°48° AprMay: average high 80 °F, low 58 °F 80°58° MayJune: average high 87 °F, low 66 °F 87°66° JunJuly: average high 90 °F, low 69 °F 90°69° JulAugust: average high 90 °F, low 67 °F 90°67° AugSeptember: average high 84 °F, low 60 °F 84°60° SepOctober: average high 73 °F, low 48 °F 73°48° OctNovember: average high 61 °F, low 38 °F 61°38° NovDecember: average high 51 °F, low 32 °F 51°32° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 4.07 in precipitation 4.1 JanFebruary: 4.40 in precipitation 4.4 FebMarch: 5.55 in precipitation 5.5 MarApril: 5.12 in precipitation 5.1 AprMay: 5.58 in precipitation 5.6 MayJune: 4.76 in precipitation 4.8 JunJuly: 4.37 in precipitation 4.4 JulAugust: 3.53 in precipitation 3.5 AugSeptember: 3.58 in precipitation 3.6 SepOctober: 3.63 in precipitation 3.6 OctNovember: 4.33 in precipitation 4.3 NovDecember: 5.01 in precipitation 5.0 Dec

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

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7b.

383927b
Mercer, TN · 6 mi
383017b
Jackson, TN · 8 mi
383567b
Medon, TN · 9 mi
383027b
Jackson, TN · 10 mi
383037b
Jackson, TN · 10 mi
383087b
Jackson, TN · 10 mi
383147b
Jackson, TN · 10 mi
380067b
Bells, TN · 12 mi

Tennessee planting zones →

Questions about 38391

What planting zone is ZIP code 38391?

ZIP code 38391 (Denmark, 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 Denmark, TN?

The median last spring frost (32 °F) near 38391 is April 5; after April 21 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Jackson Mckellar Airport station.

When is the first frost in Denmark, TN?

The median first fall frost near 38391 is October 29, giving a median frost-free growing season of 207 days.

When should I plant tomatoes in 38391?

Start tomato seeds indoors around Feb 8 – Feb 22 and set transplants outside around Apr 12 – Apr 26, one to three weeks after the median last frost.

How much rain and snow does 38391 get?

About 53.9 inches of precipitation a year (NOAA 1991–2020 normals, Jackson Mckellar Airport station).

How hot do summers get in Denmark, TN?

The average high peaks at 90 °F in July, with about 58 days a year at 90 °F or more.

What kind of soil does 38391 have?

The USDA soil survey maps Lexington at the center of ZIP 38391: silt loam, well drained, pH about 5.3 (strongly acidic).

Did spring come early in Denmark, TN in 2026?

Spring leaf-out near 38391 came on Feb 18 in 2026, 3 days earlier than the 1991–2020 average (Feb 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Denmark, TN?

Intermediate onions: the longest day near 38391 is 14 h 34 min, so day-neutral types bulb best; long-day varieties may not bulb fully.