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

Planting zone for 47228 — Cortland, IN

ZIP code 47228 (Cortland, Jackson County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 16 and the first fall frost October 21.

Where ZIP 47228 is

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.

Zone6b−5 to 0 °F
Coldest night−20.6 to −17.8 °C
Last frostApr 16
First frostOct 21
2012 zone6a

Was 6a 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 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Cortland, 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 Cortland, IN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 16median — 50% chance of a later frost
Safe for tender plantsMay 2only 10% chance of frost after
First fall frostOctober 21median — 10% chance by Oct 7
Growing season187 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 2 and returns around November 1.

From the NOAA station Seymour 2 N, IN — 4 miles away, elevation 571 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 47228

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 5 – Mar 19
SpinachSow outdoors · Mar 5 – Mar 26
Broccoli, cabbageStart indoors · Feb 5 – Feb 19
Broccoli, cabbageTransplant · Mar 26 – Apr 9
Onion setsPlant outdoors · Mar 19 – Apr 2
PotatoesPlant outdoors · Mar 26 – Apr 9
LettuceSow outdoors · Mar 19 – Apr 2
Carrots, beetsSow outdoors · Mar 26 – Apr 9
TomatoesStart indoors · Feb 19 – Mar 5
TomatoesTransplant · Apr 23 – May 7
Peppers, eggplantStart indoors · Feb 5 – Feb 19
Peppers, eggplantTransplant · Apr 30 – May 14
BeansSow outdoors · Apr 23 – May 7
Sweet cornSow outdoors · Apr 23 – May 7
Cucumbers, squashSow outdoors · Apr 23 – May 7
Fall lettuce, spinachSow outdoors · Aug 26 – Sep 9
GarlicPlant cloves · Oct 7 – Nov 11
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 16) and first fall frost (Oct 21) 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 47228 came on Mar 8 — 13 days earlier than the 1991–2020 average (Mar 21).

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 6b in Indiana

564 plants native to the lower 48 states, recorded in Indiana, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. Each links to its USDA PLANTS profile.

Trees 72

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 105

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 202

American 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 °FAmerican speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °F

Grasses 162

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fautumn bluegrass1.5 ft · blooms late spring · medium shade tolerance · to −8 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °FBebb's sedge3 ft · blooms late spring · low shade tolerance · to −38 °F

Vines 11

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fcatbird grape30 ft · blooms late spring · medium shade tolerance · to −13 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium shade tolerance · to −23 °Fgraybark grape50 ft · blooms late spring · medium shade tolerance · to −8 °Fheartleaf peppervine2 ft · blooms late spring · low shade tolerance · to −8 °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 Cortland, IN.

Soil in Cortland, IN

The soil mapped at the center of ZIP 47228 is Martinsville — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding
pH5.9moderately acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Martinsville sandy loam, sandy substratum, 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 47228; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Cortland, IN

Summer high85 °Faverage high, July
Winter low22 °Faverage low, January
Hot days20days a year at 90 °F or more
Freezing nights117nights a year at 32 °F or less
Growing degree days3,496base 50 °F — the season’s usable heat
Longest day14 h 54 mindaylight on June 21
Shortest day9 h 26 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation49.6 inper year, rain and melted snow
Snowfall8 inper year

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 38 °F, low 22 °F 38°22° JanFebruary: average high 42 °F, low 24 °F 42°24° FebMarch: average high 52 °F, low 32 °F 52°32° MarApril: average high 65 °F, low 42 °F 65°42° AprMay: average high 74 °F, low 53 °F 74°53° MayJune: average high 82 °F, low 61 °F 82°61° JunJuly: average high 85 °F, low 64 °F 85°64° JulAugust: average high 84 °F, low 62 °F 84°62° AugSeptember: average high 78 °F, low 54 °F 78°54° SepOctober: average high 67 °F, low 42 °F 67°42° OctNovember: average high 53 °F, low 33 °F 53°33° NovDecember: average high 42 °F, low 26 °F 42°26° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 3.39 in precipitation, 2.8 in snowfall 3.4❄3 JanFebruary: 3.09 in precipitation, 1.8 in snowfall 3.1❄2 FebMarch: 4.26 in precipitation, 2 in snowfall 4.3❄2 MarApril: 5.43 in precipitation 5.4 AprMay: 5.43 in precipitation 5.4 MayJune: 4.99 in precipitation 5.0 JunJuly: 4.18 in precipitation 4.2 JulAugust: 4.31 in precipitation 4.3 AugSeptember: 3.36 in precipitation 3.4 SepOctober: 3.59 in precipitation, 0.2 in snowfall 3.6 OctNovember: 3.72 in precipitation, 0.1 in snowfall 3.7 NovDecember: 3.82 in precipitation, 1.1 in snowfall 3.8❄1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Seymour 2 N, IN (4 mi away); precipitation: Seymour 2 N, IN (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6b.

472746b
Seymour, IN · 2 mi
472206b
Brownstown, IN · 8 mi
472356b
Freetown, IN · 10 mi
472456b
Hayden, IN · 12 mi
472016b
Columbus, IN · 12 mi
472296b
Crothersville, IN · 13 mi
472496b
Kurtz, IN · 13 mi
472326b
Elizabethtown, IN · 13 mi

Indiana planting zones →

Questions about 47228

What planting zone is ZIP code 47228?

ZIP code 47228 (Cortland, IN) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Cortland, IN?

The median last spring frost (32 °F) near 47228 is April 16; after May 2 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Seymour 2 N station.

When is the first frost in Cortland, IN?

The median first fall frost near 47228 is October 21, giving a median frost-free growing season of 187 days.

When should I plant tomatoes in 47228?

Start tomato seeds indoors around Feb 19 – Mar 5 and set transplants outside around Apr 23 – May 7, one to three weeks after the median last frost.

How much rain and snow does 47228 get?

About 49.6 inches of precipitation a year and 8 inches of snowfall (NOAA 1991–2020 normals, Seymour 2 N station).

How hot do summers get in Cortland, IN?

The average high peaks at 85 °F in July, with about 20 days a year at 90 °F or more.

What kind of soil does 47228 have?

The USDA soil survey maps Martinsville at the center of ZIP 47228: sandy loam, well drained, pH about 5.9 (moderately acidic).

Did spring come early in Cortland, IN in 2026?

Spring leaf-out near 47228 came on Mar 8 in 2026, 13 days earlier than the 1991–2020 average (Mar 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Cortland, IN?

Intermediate onions: the longest day near 47228 is 14 h 54 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 47228 change?

Yes. The 2012 USDA map put 47228 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.