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

Planting zone for 68730 — Crofton, NE

ZIP code 68730 (Crofton, Knox County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is April 30 and the first fall frost October 8.

Where ZIP 68730 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.

Zone5a−20 to −15 °F

Coldest night−28.9 to −26.1 °C

Last frostApr 30

First frostOct 8

2012 zone5a

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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Crofton, NE…

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 Crofton, NE

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 30median — 50% chance of a later frost

Safe for tender plantsMay 13only 10% chance of frost after

First fall frostOctober 8median — 10% chance by Sep 26

Growing season160 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 20 and returns around October 18.

From the NOAA station Crofton, NE — 3 miles away, elevation 1,401 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 68730

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 19 – Apr 2

SpinachSow outdoors · Mar 19 – Apr 9

Broccoli, cabbageStart indoors · Feb 19 – Mar 5

Broccoli, cabbageTransplant · Apr 9 – Apr 23

Onion setsPlant outdoors · Apr 2 – Apr 16

PotatoesPlant outdoors · Apr 9 – Apr 23

LettuceSow outdoors · Apr 2 – Apr 16

Carrots, beetsSow outdoors · Apr 9 – Apr 23

TomatoesStart indoors · Mar 5 – Mar 19

TomatoesTransplant · May 7 – May 21

Peppers, eggplantStart indoors · Feb 19 – Mar 5

Peppers, eggplantTransplant · May 14 – May 28

BeansSow outdoors · May 7 – May 21

Sweet cornSow outdoors · May 7 – May 21

Cucumbers, squashSow outdoors · May 7 – May 21

Fall lettuce, spinachSow outdoors · Aug 13 – Aug 27

GarlicPlant cloves · Sep 24 – Oct 29

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 30) and first fall frost (Oct 8) 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 68730 came on Mar 19 — 19 days earlier than the 1991–2020 average (Apr 7).

average
Apr 72026
Mar 19

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 5a in Nebraska

413 plants native to the lower 48 states, recorded in Nebraska, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. 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 Crofton, NE.

Soil in Crofton, NE

The soil mapped at the center of ZIP 68730 is Trent — silt loam, well drained.

TextureSilt loama good balance for most vegetables

pH6.0slightly acidic; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter5.25%high

Hydrologic groupCwater soaks in slowly

Farmland classprime farmlandUSDA classification

Map unit: Trent silt loam, 0 to 2 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 68730; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Crofton, NE

Summer high85 °Faverage high, July

Winter low10 °Faverage low, January

Hot days21days a year at 90 °F or more

Freezing nights154nights a year at 32 °F or less

Growing degree days3,031base 50 °F — the season’s usable heat

Longest day15 h 20 mindaylight on June 21

Shortest day9 h 02 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation29 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: Crofton, NE (3 mi away); precipitation: Crofton 4.4 Wnw, NE (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

2 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

687365a

Fordyce, NE · 8 mi

687185b

Bloomfield, NE · 10 mi

570785a

Yankton, SD · 11 mi

687745a

Saint Helena, NE · 14 mi

570635a

Tabor, SD · 14 mi

687395b

Hartington, NE · 17 mi

570465a

Mission Hill, SD · 18 mi

687605a

Niobrara, NE · 18 mi

Nebraska planting zones →

Questions about 68730

What planting zone is ZIP code 68730?

ZIP code 68730 (Crofton, NE) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Crofton, NE?

The median last spring frost (32 °F) near 68730 is April 30; after May 13 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Crofton station.

When is the first frost in Crofton, NE?

The median first fall frost near 68730 is October 8, giving a median frost-free growing season of 160 days.

When should I plant tomatoes in 68730?

Start tomato seeds indoors around Mar 5 – Mar 19 and set transplants outside around May 7 – May 21, one to three weeks after the median last frost.

How much rain and snow does 68730 get?

About 29 inches of precipitation a year (NOAA 1991–2020 normals, Crofton 4.4 Wnw station).

How hot do summers get in Crofton, NE?

The average high peaks at 85 °F in July, with about 21 days a year at 90 °F or more.

What kind of soil does 68730 have?

The USDA soil survey maps Trent at the center of ZIP 68730: silt loam, well drained, pH about 6.0 (slightly acidic).

Did spring come early in Crofton, NE in 2026?

Spring leaf-out near 68730 came on Mar 19 in 2026, 19 days earlier than the 1991–2020 average (Apr 7), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Crofton, NE?

Long-day onions: the longest day near 68730 is 15 h 20 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).