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

Planting zone for 56726 — Greenbush, MN

ZIP code 56726 (Greenbush, Roseau County) is in USDA zone 3b: the coldest winter night averages −35 to −30 °F. The median last spring frost is May 6 and the first fall frost October 3.

Where ZIP 56726 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.

Zone3b−35 to −30 °F

Coldest night−37.2 to −34.4 °C

Last frostMay 6

First frostOct 3

2012 zone3a

Was 3a 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 3b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Greenbush, MN…

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 Greenbush, MN

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 6median — 50% chance of a later frost

Safe for tender plantsMay 20only 10% chance of frost after

First fall frostOctober 3median — 10% chance by Sep 20

Growing season148 daysfrost-free, median

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

From the NOAA station Agassiz Refuge, MN — 31 miles away, elevation 1,142 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 56726

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 25 – Apr 8

SpinachSow outdoors · Mar 25 – Apr 15

Broccoli, cabbageStart indoors · Feb 25 – Mar 11

Broccoli, cabbageTransplant · Apr 15 – Apr 29

Onion setsPlant outdoors · Apr 8 – Apr 22

PotatoesPlant outdoors · Apr 15 – Apr 29

LettuceSow outdoors · Apr 8 – Apr 22

Carrots, beetsSow outdoors · Apr 15 – Apr 29

TomatoesStart indoors · Mar 11 – Mar 25

TomatoesTransplant · May 13 – May 27

Peppers, eggplantStart indoors · Feb 25 – Mar 11

Peppers, eggplantTransplant · May 20 – Jun 3

BeansSow outdoors · May 13 – May 27

Sweet cornSow outdoors · May 13 – May 27

Cucumbers, squashSow outdoors · May 13 – May 27

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 6) 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 56726 came on May 6 — 9 days later than the 1991–2020 average (Apr 27).

average
Apr 272026
May 6

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 3b in Minnesota

287 plants native to the lower 48 states, recorded in Minnesota, and rated by the USDA to survive −35 °F or colder — the bottom of zone 3b. 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 Greenbush, MN.

Soil in Greenbush, MN

The soil mapped at the center of ZIP 56726 is Percy — loam, poorly drained.

TextureLoama good balance for most vegetables

pH7.5slightly alkaline; most vegetables like 6.0–7.0

DrainagePoorly drainedconsider raised beds

Organic matter6.5%high

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classNot prime farmlandUSDA classification

Map unit: Percy loam, 0 to 1 percent slopes, very cobbly.

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 56726; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Greenbush, MN

Summer high81 °Faverage high, July

Winter low−3 °Faverage low, January

Hot days4days a year at 90 °F or more

Freezing nights183nights a year at 32 °F or less

Growing degree days2,275base 50 °F — the season’s usable heat

Longest day16 h 10 mindaylight on June 21

Shortest day8 h 16 mindaylight on December 21

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

Precipitation24.4 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: Agassiz Refuge, MN (31 mi away); precipitation: Agassiz Refuge, MN (31 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 3b.

567143b

Badger, MN · 11 mi

567593b

Strathcona, MN · 14 mi

Lake Bronson, MN · 18 mi

567513b

Roseau, MN · 22 mi

567353b

Lancaster, MN · 23 mi

567583b

Strandquist, MN · 23 mi

Minnesota planting zones →

Questions about 56726

What planting zone is ZIP code 56726?

ZIP code 56726 (Greenbush, MN) is in USDA hardiness zone 3b on the 2023 map: the coldest night of an average winter reaches −35 to −30 °F (−37.2 to −34.4 °C).

When is the last frost in Greenbush, MN?

The median last spring frost (32 °F) near 56726 is May 6; after May 20 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Agassiz Refuge station.

When is the first frost in Greenbush, MN?

The median first fall frost near 56726 is October 3, giving a median frost-free growing season of 148 days.

When should I plant tomatoes in 56726?

Start tomato seeds indoors around Mar 11 – Mar 25 and set transplants outside around May 13 – May 27, one to three weeks after the median last frost.

How much rain and snow does 56726 get?

About 24.4 inches of precipitation a year (NOAA 1991–2020 normals, Agassiz Refuge station).

How hot do summers get in Greenbush, MN?

The average high peaks at 81 °F in July, with about 4 days a year at 90 °F or more.

What kind of soil does 56726 have?

The USDA soil survey maps Percy at the center of ZIP 56726: loam, poorly drained, pH about 7.5 (slightly alkaline).

Did spring come early in Greenbush, MN in 2026?

Spring leaf-out near 56726 came on May 6 in 2026, 9 days later than the 1991–2020 average (Apr 27), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Greenbush, MN?

Long-day onions: the longest day near 56726 is 16 h 10 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 56726 change?

Yes. The 2012 USDA map put 56726 in zone 3a; the 2023 map puts it in zone 3b. The newer map uses 1991–2020 data and more weather stations.