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

Planting zone for 66540 — Soldier, KS

ZIP code 66540 (Soldier, Jackson County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 24 and the first fall frost October 14.

Where ZIP 66540 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.

Zone6a−10 to −5 °F

Coldest night−23.3 to −20.6 °C

Last frostApr 24

First frostOct 14

2012 zone6a

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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Soldier, KS…

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 Soldier, KS

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 24median — 50% chance of a later frost

Safe for tender plantsMay 7only 10% chance of frost after

First fall frostOctober 14median — 10% chance by Sep 29

Growing season172 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 13 and returns around October 24.

From the NOAA station Holton, KS — 12 miles away, elevation 1,050 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 66540

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 13 – Mar 27

SpinachSow outdoors · Mar 13 – Apr 3

Broccoli, cabbageStart indoors · Feb 13 – Feb 27

Broccoli, cabbageTransplant · Apr 3 – Apr 17

Onion setsPlant outdoors · Mar 27 – Apr 10

PotatoesPlant outdoors · Apr 3 – Apr 17

LettuceSow outdoors · Mar 27 – Apr 10

Carrots, beetsSow outdoors · Apr 3 – Apr 17

TomatoesStart indoors · Feb 27 – Mar 13

TomatoesTransplant · May 1 – May 15

Peppers, eggplantStart indoors · Feb 13 – Feb 27

Peppers, eggplantTransplant · May 8 – May 22

BeansSow outdoors · May 1 – May 15

Sweet cornSow outdoors · May 1 – May 15

Cucumbers, squashSow outdoors · May 1 – May 15

Fall lettuce, spinachSow outdoors · Aug 19 – Sep 2

GarlicPlant cloves · Sep 30 – Nov 4

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 24) and first fall frost (Oct 14) 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 66540 came on Feb 28 — 21 days earlier than the 1991–2020 average (Mar 21).

average
Mar 212026
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 6a in Kansas

425 plants native to the lower 48 states, recorded in Kansas, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. 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 Soldier, KS.

Soil in Soldier, KS

The soil mapped at the center of ZIP 66540 is Martin — silty clay loam, moderately well drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up

pH6.1slightly acidic; most vegetables like 6.0–7.0

DrainageModerately well drainednatural drainage class

Organic matter3.7%moderate

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classprime farmlandUSDA classification

Map unit: Martin silty clay loam, 3 to 7 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 66540; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Soldier, KS

Summer high88 °Faverage high, July

Winter low15 °Faverage low, January

Hot days38days a year at 90 °F or more

Freezing nights131nights a year at 32 °F or less

Growing degree days3,610base 50 °F — the season’s usable heat

Longest day14 h 58 mindaylight on June 21

Shortest day9 h 23 mindaylight on December 21

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

Precipitation35.5 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: Holton, KS (12 mi away); precipitation: Circleville 7 Sw, KS (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

664326a

Havensville, KS · 6 mi

664166a

Circleville, KS · 6 mi

Kansas planting zones →

Questions about 66540

What planting zone is ZIP code 66540?

ZIP code 66540 (Soldier, KS) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Soldier, KS?

The median last spring frost (32 °F) near 66540 is April 24; after May 7 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Holton station.

When is the first frost in Soldier, KS?

The median first fall frost near 66540 is October 14, giving a median frost-free growing season of 172 days.

When should I plant tomatoes in 66540?

Start tomato seeds indoors around Feb 27 – Mar 13 and set transplants outside around May 1 – May 15, one to three weeks after the median last frost.

How much rain and snow does 66540 get?

About 35.5 inches of precipitation a year (NOAA 1991–2020 normals, Circleville 7 Sw station).

How hot do summers get in Soldier, KS?

The average high peaks at 88 °F in July, with about 38 days a year at 90 °F or more.

What kind of soil does 66540 have?

The USDA soil survey maps Martin at the center of ZIP 66540: silty clay loam, moderately well drained, pH about 6.1 (slightly acidic).

Did spring come early in Soldier, KS in 2026?

Spring leaf-out near 66540 came on Feb 28 in 2026, 21 days earlier than the 1991–2020 average (Mar 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Soldier, KS?

Intermediate onions: the longest day near 66540 is 14 h 58 min, so day-neutral types bulb best; long-day varieties may not bulb fully.