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

Planting zone for 46103 — Amo, IN

ZIP code 46103 (Amo, Hendricks County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 27 and the first fall frost October 15.

Where ZIP 46103 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 27

First frostOct 15

2012 zone5b

Was 5b 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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Amo, IN…

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 Amo, IN

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 27median — 50% chance of a later frost

Safe for tender plantsMay 15only 10% chance of frost after

First fall frostOctober 15median — 10% chance by Oct 1

Growing season169 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 15 and returns around October 26.

From the NOAA station Greencastle 1 W, IN — 14 miles away, elevation 735 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 46103

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 16 – Mar 30

SpinachSow outdoors · Mar 16 – Apr 6

Broccoli, cabbageStart indoors · Feb 16 – Mar 2

Broccoli, cabbageTransplant · Apr 6 – Apr 20

Onion setsPlant outdoors · Mar 30 – Apr 13

PotatoesPlant outdoors · Apr 6 – Apr 20

LettuceSow outdoors · Mar 30 – Apr 13

Carrots, beetsSow outdoors · Apr 6 – Apr 20

TomatoesStart indoors · Mar 2 – Mar 16

TomatoesTransplant · May 4 – May 18

Peppers, eggplantStart indoors · Feb 16 – Mar 2

Peppers, eggplantTransplant · May 11 – May 25

BeansSow outdoors · May 4 – May 18

Sweet cornSow outdoors · May 4 – May 18

Cucumbers, squashSow outdoors · May 4 – May 18

Fall lettuce, spinachSow outdoors · Aug 20 – Sep 3

GarlicPlant cloves · Oct 1 – Nov 5

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 27) and first fall frost (Oct 15) 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 46103 came on Mar 10 — 16 days earlier than the 1991–2020 average (Mar 26).

average
Mar 262026
Mar 10

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 Indiana

558 plants native to the lower 48 states, recorded in Indiana, 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 Amo, IN.

Soil in Amo, IN

The soil mapped at the center of ZIP 46103 is Whitaker — silt loam, somewhat poorly drained.

TextureSilt loama good balance for most vegetables

pH6.0slightly 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 drainedUSDA classification

Map unit: Whitaker 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 46103; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Amo, IN

Summer high83 °Faverage high, July

Winter low17 °Faverage low, January

Hot days15days a year at 90 °F or more

Freezing nights124nights a year at 32 °F or less

Growing degree days3,059base 50 °F — the season’s usable heat

Longest day14 h 59 mindaylight on June 21

Shortest day9 h 21 mindaylight on December 21

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

Precipitation44.8 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: Greencastle 1 W, IN (14 mi away); precipitation: Clayton 0.4 Wnw, IN (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

461216a

Coatesville, IN · 4 mi

461186a

Clayton, IN · 5 mi

461806a

Stilesville, IN · 7 mi

North Salem, IN · 11 mi

461256a

Eminence, IN · 12 mi

Indiana planting zones →

Questions about 46103

What planting zone is ZIP code 46103?

ZIP code 46103 (Amo, IN) 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 Amo, IN?

The median last spring frost (32 °F) near 46103 is April 27; after May 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Greencastle 1 W station.

When is the first frost in Amo, IN?

The median first fall frost near 46103 is October 15, giving a median frost-free growing season of 169 days.

When should I plant tomatoes in 46103?

Start tomato seeds indoors around Mar 2 – Mar 16 and set transplants outside around May 4 – May 18, one to three weeks after the median last frost.

How much rain and snow does 46103 get?

About 44.8 inches of precipitation a year (NOAA 1991–2020 normals, Clayton 0.4 Wnw station).

How hot do summers get in Amo, IN?

The average high peaks at 83 °F in July, with about 15 days a year at 90 °F or more.

What kind of soil does 46103 have?

The USDA soil survey maps Whitaker at the center of ZIP 46103: silt loam, somewhat poorly drained, pH about 6.0 (slightly acidic).

Did spring come early in Amo, IN in 2026?

Spring leaf-out near 46103 came on Mar 10 in 2026, 16 days earlier than the 1991–2020 average (Mar 26), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Amo, IN?

Intermediate onions: the longest day near 46103 is 14 h 59 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 46103 change?

Yes. The 2012 USDA map put 46103 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.