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

Planting zone for 56629 — Birchdale, MN

ZIP code 56629 (Birchdale, Koochiching County) is in USDA zone 3b: the coldest winter night averages −35 to −30 °F. The median last spring frost is May 23 and the first fall frost September 21.

Where ZIP 56629 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 23
First frostSep 21
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 Birchdale, 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 Birchdale, MN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 23median — 50% chance of a later frost
Safe for tender plantsJune 5only 10% chance of frost after
First fall frostSeptember 21median — 10% chance by Sep 4
Growing season118 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 10 and returns around October 1.

From the NOAA station Littlefork 10 Sw, MN — 22 miles away, elevation 1,201 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 56629

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 11 – Apr 25
SpinachSow outdoors · Apr 11 – May 2
Broccoli, cabbageStart indoors · Mar 14 – Mar 28
Broccoli, cabbageTransplant · May 2 – May 16
Onion setsPlant outdoors · Apr 25 – May 9
PotatoesPlant outdoors · May 2 – May 16
LettuceSow outdoors · Apr 25 – May 9
Carrots, beetsSow outdoors · May 2 – May 16
TomatoesStart indoors · Mar 28 – Apr 11
TomatoesTransplant · May 30 – Jun 13
Peppers, eggplantStart indoors · Mar 14 – Mar 28
Peppers, eggplantTransplant · Jun 6 – Jun 20
BeansSow outdoors · May 30 – Jun 13
Sweet cornSow outdoors · May 30 – Jun 13
Cucumbers, squashSow outdoors · May 30 – Jun 13
Fall lettuce, spinachSow outdoors · Jul 27 – Aug 10
GarlicPlant cloves · Sep 7 – Oct 12
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 23) and first fall frost (Sep 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 56629 came on May 9 — 12 days later than the 1991–2020 average (Apr 27).

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.

Trees 33

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °Fbalsam fir60 ft · blooms mid summer · low shade tolerance · to −43 °Fbalsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °Fbigtooth aspen65 ft · blooms mid spring · high shade tolerance · to −43 °F

Shrubs 50

Allegheny 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 mountain ash40 ft · blooms early summer · medium shade tolerance · to −38 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °Fbeaked hazelnut15 ft · blooms early spring · low shade tolerance · to −47 °F

Wildflowers & perennials 102

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °FAmerican vetch1.3 ft · blooms late spring · high shade tolerance · to −38 °F

Grasses 93

alkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °Fbasin wildrye5 ft · blooms early spring · high shade tolerance · to −43 °Fbeaked sedge4 ft · blooms late 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 °F

Vines 2

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °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 Birchdale, MN.

Soil in Birchdale, MN

The soil mapped at the center of ZIP 56629 is Greenwood — peat, very poorly drained.

TexturePeattop layer
DrainageVery poorly drainedconsider raised beds
Organic matter95%high
Hydrologic groupA/Ddrains fast once dried out; wet otherwise
Farmland classNot prime farmlandUSDA classification

Map unit: Greenwood-Lobo complex, 0 to 1 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 56629; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Birchdale, MN

Summer high78 °Faverage high, July
Winter low−8 °Faverage low, January
Hot days2days a year at 90 °F or more
Freezing nights200nights a year at 32 °F or less
Growing degree days1,660base 50 °F — the season’s usable heat
Longest day16 h 08 mindaylight on June 21
Shortest day8 h 18 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation26.9 inper year, rain and melted snow

Average high and low, by month

−20°−10°0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 15 °F, low -8 °F 15°−8° JanFebruary: average high 22 °F, low -4 °F 22°−4° FebMarch: average high 36 °F, low 11 °F 36°11° MarApril: average high 50 °F, low 27 °F 50°27° AprMay: average high 64 °F, low 39 °F 64°39° MayJune: average high 73 °F, low 50 °F 73°50° JunJuly: average high 78 °F, low 54 °F 78°54° JulAugust: average high 76 °F, low 52 °F 76°52° AugSeptember: average high 67 °F, low 43 °F 67°43° SepOctober: average high 52 °F, low 31 °F 52°31° OctNovember: average high 35 °F, low 18 °F 35°18° NovDecember: average high 22 °F, low 2 °F 22°2° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 0.84 in precipitation 0.8 JanFebruary: 0.56 in precipitation 0.6 FebMarch: 0.91 in precipitation 0.9 MarApril: 1.54 in precipitation 1.5 AprMay: 3.26 in precipitation 3.3 MayJune: 4.52 in precipitation 4.5 JunJuly: 4.48 in precipitation 4.5 JulAugust: 3.31 in precipitation 3.3 AugSeptember: 2.89 in precipitation 2.9 SepOctober: 2.18 in precipitation 2.2 OctNovember: 1.40 in precipitation 1.4 NovDecember: 0.97 in precipitation 1.0 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Littlefork 10 Sw, MN (22 mi away); precipitation: Indus 3 W, MN (14 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

566543a
Loman, MN · 11 mi
566233b
Baudette, MN · 21 mi
566273b
Big Falls, MN · 23 mi
566853b
Waskish, MN · 25 mi
566583b
Margie, MN · 30 mi
566533b
Littlefork, MN · 31 mi
566793b
South International Falls, MN · 35 mi
566603b
Mizpah, MN · 36 mi

Minnesota planting zones →

Questions about 56629

What planting zone is ZIP code 56629?

ZIP code 56629 (Birchdale, 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 Birchdale, MN?

The median last spring frost (32 °F) near 56629 is May 23; after June 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Littlefork 10 Sw station.

When is the first frost in Birchdale, MN?

The median first fall frost near 56629 is September 21, giving a median frost-free growing season of 118 days.

When should I plant tomatoes in 56629?

Start tomato seeds indoors around Mar 28 – Apr 11 and set transplants outside around May 30 – Jun 13, one to three weeks after the median last frost.

How much rain and snow does 56629 get?

About 26.9 inches of precipitation a year (NOAA 1991–2020 normals, Indus 3 W station).

How hot do summers get in Birchdale, MN?

The average high peaks at 78 °F in July, with about 2 days a year at 90 °F or more.

What kind of soil does 56629 have?

The USDA soil survey maps Greenwood at the center of ZIP 56629: peat, very poorly drained.

Did spring come early in Birchdale, MN in 2026?

Spring leaf-out near 56629 came on May 9 in 2026, 12 days later than the 1991–2020 average (Apr 27), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Birchdale, MN?

Long-day onions: the longest day near 56629 is 16 h 08 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 56629 change?

Yes. The 2012 USDA map put 56629 in zone 3a; the 2023 map puts it in zone 3b. The newer map uses 1991–2020 data and more weather stations.