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

Planting zone for 40949 — Heidrick, KY

ZIP code 40949 (Heidrick, Knox County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is April 19 and the first fall frost October 24.

Where ZIP 40949 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 19
First frostOct 24
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 Heidrick, KY…

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 Heidrick, KY

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 19median — 50% chance of a later frost
Safe for tender plantsMay 6only 10% chance of frost after
First fall frostOctober 24median — 10% chance by Oct 11
Growing season187 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 6 and returns around November 1.

From the NOAA station Barbourville, KY — within 1 mile, elevation 991 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 40949

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 8 – Mar 22
SpinachSow outdoors · Mar 8 – Mar 29
Broccoli, cabbageStart indoors · Feb 8 – Feb 22
Broccoli, cabbageTransplant · Mar 29 – Apr 12
Onion setsPlant outdoors · Mar 22 – Apr 5
PotatoesPlant outdoors · Mar 29 – Apr 12
LettuceSow outdoors · Mar 22 – Apr 5
Carrots, beetsSow outdoors · Mar 29 – Apr 12
TomatoesStart indoors · Feb 22 – Mar 8
TomatoesTransplant · Apr 26 – May 10
Peppers, eggplantStart indoors · Feb 8 – Feb 22
Peppers, eggplantTransplant · May 3 – May 17
BeansSow outdoors · Apr 26 – May 10
Sweet cornSow outdoors · Apr 26 – May 10
Cucumbers, squashSow outdoors · Apr 26 – May 10
Fall lettuce, spinachSow outdoors · Aug 29 – Sep 12
GarlicPlant cloves · Oct 10 – Nov 14
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 19) and first fall frost (Oct 24) 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 40949 came on Mar 2 — 5 days earlier than the 1991–2020 average (Mar 7).

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 Kentucky

547 plants native to the lower 48 states, recorded in Kentucky, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. Each links to its USDA PLANTS profile.

Trees 78

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 109

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 black currant3 ft · blooms early spring · to −46 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican holly40 ft · blooms mid spring · low shade tolerance · to −20 °F

Wildflowers & perennials 181

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 153

autumn 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 °Fblister sedge3 ft · blooms late spring · medium shade tolerance · to −38 °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 Heidrick, KY.

Soil in Heidrick, KY

The soil mapped at the center of ZIP 40949 is Stendal — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables
pH5.5moderately acidic; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter2%moderate
Hydrologic groupB/Dmoderate when drained; wet otherwise
Farmland classPrime farmland if drained and either protected from flooding or not frequently flooded during the growing seasonUSDA classification

Map unit: Stendal silt loam, frequently 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 40949; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Heidrick, KY

Summer high87 °Faverage high, July
Winter low25 °Faverage low, January
Hot days29days a year at 90 °F or more
Freezing nights110nights a year at 32 °F or less
Growing degree days3,895base 50 °F — the season’s usable heat
Longest day14 h 42 mindaylight on June 21
Shortest day9 h 38 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation53.8 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 45 °F, low 25 °F 45°25° JanFebruary: average high 50 °F, low 28 °F 50°28° FebMarch: average high 59 °F, low 33 °F 59°33° MarApril: average high 69 °F, low 41 °F 69°41° AprMay: average high 77 °F, low 51 °F 77°51° MayJune: average high 84 °F, low 60 °F 84°60° JunJuly: average high 87 °F, low 65 °F 87°65° JulAugust: average high 86 °F, low 64 °F 86°64° AugSeptember: average high 81 °F, low 56 °F 81°56° SepOctober: average high 71 °F, low 44 °F 71°44° OctNovember: average high 58 °F, low 33 °F 58°33° NovDecember: average high 49 °F, low 28 °F 49°28° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 4.37 in precipitation 4.4 JanFebruary: 4.35 in precipitation 4.3 FebMarch: 4.91 in precipitation 4.9 MarApril: 5.08 in precipitation 5.1 AprMay: 4.54 in precipitation 4.5 MayJune: 5.11 in precipitation 5.1 JunJuly: 5.77 in precipitation 5.8 JulAugust: 3.98 in precipitation 4.0 AugSeptember: 3.45 in precipitation 3.5 SepOctober: 3.13 in precipitation 3.1 OctNovember: 3.82 in precipitation 3.8 NovDecember: 5.26 in precipitation 5.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Barbourville, KY (within 1 mile); precipitation: Barbourville, KY (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

409067a
Barbourville, KY · <1 mi
409237a
Cannon, KY · 2 mi
409157a
Bimble, KY · 3 mi
409437a
Girdler, KY · 4 mi
409537a
Hinkle, KY · 4 mi
409467a
Green Road, KY · 5 mi
407347a
Gray, KY · 6 mi
409357a
Flat Lick, KY · 8 mi

Kentucky planting zones →

Questions about 40949

What planting zone is ZIP code 40949?

ZIP code 40949 (Heidrick, KY) 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 Heidrick, KY?

The median last spring frost (32 °F) near 40949 is April 19; after May 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Barbourville station.

When is the first frost in Heidrick, KY?

The median first fall frost near 40949 is October 24, giving a median frost-free growing season of 187 days.

When should I plant tomatoes in 40949?

Start tomato seeds indoors around Feb 22 – Mar 8 and set transplants outside around Apr 26 – May 10, one to three weeks after the median last frost.

How much rain and snow does 40949 get?

About 53.8 inches of precipitation a year (NOAA 1991–2020 normals, Barbourville station).

How hot do summers get in Heidrick, KY?

The average high peaks at 87 °F in July, with about 29 days a year at 90 °F or more.

What kind of soil does 40949 have?

The USDA soil survey maps Stendal at the center of ZIP 40949: silt loam, somewhat poorly drained, pH about 5.5 (moderately acidic).

Did spring come early in Heidrick, KY in 2026?

Spring leaf-out near 40949 came on Mar 2 in 2026, 5 days earlier than the 1991–2020 average (Mar 7), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Heidrick, KY?

Intermediate onions: the longest day near 40949 is 14 h 42 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 40949 change?

Yes. The 2012 USDA map put 40949 in zone 6b; the 2023 map puts it in zone 7a. The newer map uses 1991–2020 data and more weather stations.