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

Planting zone for 52346 — Van Horne, IA

ZIP code 52346 (Van Horne, Benton County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is May 3 and the first fall frost October 3.

Where ZIP 52346 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 frostMay 3
First frostOct 3
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 Van Horne, IA…

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 Van Horne, IA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 3median — 50% chance of a later frost
Safe for tender plantsMay 17only 10% chance of frost after
First fall frostOctober 3median — 10% chance by Sep 20
Growing season151 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 25 and returns around October 12.

From the NOAA station Vinton, IA — 12 miles away, elevation 850 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 52346

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 22 – Apr 5
SpinachSow outdoors · Mar 22 – Apr 12
Broccoli, cabbageStart indoors · Feb 22 – Mar 8
Broccoli, cabbageTransplant · Apr 12 – Apr 26
Onion setsPlant outdoors · Apr 5 – Apr 19
PotatoesPlant outdoors · Apr 12 – Apr 26
LettuceSow outdoors · Apr 5 – Apr 19
Carrots, beetsSow outdoors · Apr 12 – Apr 26
TomatoesStart indoors · Mar 8 – Mar 22
TomatoesTransplant · May 10 – May 24
Peppers, eggplantStart indoors · Feb 22 – Mar 8
Peppers, eggplantTransplant · May 17 – May 31
BeansSow outdoors · May 10 – May 24
Sweet cornSow outdoors · May 10 – May 24
Cucumbers, squashSow outdoors · May 10 – May 24
Fall lettuce, spinachSow outdoors · Aug 8 – Aug 22
GarlicPlant cloves · Sep 19 – Oct 24
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 3) and first fall frost (Oct 3) 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 52346 came on Mar 25 — 14 days earlier than the 1991–2020 average (Apr 8).

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 Iowa

461 plants native to the lower 48 states, recorded in Iowa, and rated by the USDA to survive −20 °F or colder — the bottom of zone 5a. Each links to its USDA PLANTS profile.

Trees 46

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °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 °Fbalsam fir60 ft · blooms mid summer · low shade tolerance · to −43 °F

Shrubs 77

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 hornbeam30 ft · blooms mid spring · low shade tolerance · to −34 °F

Wildflowers & perennials 185

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °FAmerican bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °F

Grasses 133

arctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBebb's sedge3 ft · blooms late spring · low shade tolerance · to −38 °FBicknell's sedge3 ft · blooms late spring · low shade tolerance · to −38 °Fbig bluestem6 ft · blooms summer · high shade tolerance · to −46 °Fblue grama1 ft · blooms early summer · high shade tolerance · to −43 °F

Vines 7

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium shade tolerance · to −23 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fsummer grape30 ft · blooms late spring · low shade tolerance · to −23 °Ftrumpet honeysuckle16 ft · blooms late summer · low shade tolerance · to −33 °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 Van Horne, IA.

Soil in Van Horne, IA

The soil mapped at the center of ZIP 52346 is Colo — silty clay loam, poorly drained.

TextureSilty clay loamholds water and nutrients; slow to drain and warm up
pH6.5neutral; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter5%high
Hydrologic groupC/Dslow when drained; wet otherwise
Farmland classPrime farmland if drainedUSDA classification

Map unit: Colo-Ely complex, 0 to 5 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 52346; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Van Horne, IA

Summer high81 °Faverage high, July
Winter low8 °Faverage low, January
Hot days11days a year at 90 °F or more
Freezing nights145nights a year at 32 °F or less
Growing degree days2,581base 50 °F — the season’s usable heat
Longest day15 h 15 mindaylight on June 21
Shortest day9 h 07 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation37.9 inper year, rain and melted snow
Snowfall34 inper year; 58 days with snow on the ground

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 26 °F, low 8 °F 26°8° JanFebruary: average high 30 °F, low 12 °F 30°12° FebMarch: average high 44 °F, low 24 °F 44°24° MarApril: average high 59 °F, low 35 °F 59°35° AprMay: average high 69 °F, low 47 °F 69°47° MayJune: average high 78 °F, low 57 °F 78°57° JunJuly: average high 81 °F, low 60 °F 81°60° JulAugust: average high 79 °F, low 58 °F 79°58° AugSeptember: average high 74 °F, low 50 °F 74°50° SepOctober: average high 60 °F, low 37 °F 60°37° OctNovember: average high 44 °F, low 25 °F 44°25° NovDecember: average high 31 °F, low 15 °F 31°15° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 1.19 in precipitation, 8.3 in snowfall 1.2❄8 JanFebruary: 1.25 in precipitation, 8.5 in snowfall 1.3❄9 FebMarch: 2.05 in precipitation, 4.4 in snowfall 2.0❄4 MarApril: 3.90 in precipitation, 1.4 in snowfall 3.9❄1 AprMay: 5.01 in precipitation 5.0 MayJune: 5.62 in precipitation 5.6 JunJuly: 4.15 in precipitation 4.2 JulAugust: 4.22 in precipitation 4.2 AugSeptember: 3.68 in precipitation 3.7 SepOctober: 3.22 in precipitation, 0.4 in snowfall 3.2 OctNovember: 2.05 in precipitation, 1.8 in snowfall 2.0❄2 NovDecember: 1.59 in precipitation, 8.8 in snowfall 1.6❄9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Vinton, IA (12 mi away); precipitation: Vinton, IA (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 5a.

523155a
Newhall, IA · 6 mi
522495a
Keystone, IA · 6 mi
522095a
Blairstown, IA · 7 mi
523545a
Watkins, IA · 8 mi
522575a
Luzerne, IA · 8 mi
522065a
Atkins, IA · 10 mi
522295a
Garrison, IA · 10 mi
523325a
Shellsburg, IA · 12 mi

Iowa planting zones →

Questions about 52346

What planting zone is ZIP code 52346?

ZIP code 52346 (Van Horne, IA) 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 Van Horne, IA?

The median last spring frost (32 °F) near 52346 is May 3; after May 17 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Vinton station.

When is the first frost in Van Horne, IA?

The median first fall frost near 52346 is October 3, giving a median frost-free growing season of 151 days.

When should I plant tomatoes in 52346?

Start tomato seeds indoors around Mar 8 – Mar 22 and set transplants outside around May 10 – May 24, one to three weeks after the median last frost.

How much rain and snow does 52346 get?

About 37.9 inches of precipitation a year and 34 inches of snowfall (NOAA 1991–2020 normals, Vinton station).

How hot do summers get in Van Horne, IA?

The average high peaks at 81 °F in July, with about 11 days a year at 90 °F or more.

What kind of soil does 52346 have?

The USDA soil survey maps Colo at the center of ZIP 52346: silty clay loam, poorly drained, pH about 6.5 (neutral).

Did spring come early in Van Horne, IA in 2026?

Spring leaf-out near 52346 came on Mar 25 in 2026, 14 days earlier than the 1991–2020 average (Apr 8), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Van Horne, IA?

Long-day onions: the longest day near 52346 is 15 h 15 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).