USDA Hardiness Zone 3B Growing Guide
Source: USDA Agricultural Research Service Plant Hardiness Zone Map 2023
Upper Midwest and northern New England — cold-hardy fruit trees and root vegetables.
Where Zone 3B sits on the national map
Zone Position
Key Facts — Zone 3B
- Avg. coldest night: -35°F to -30°F (-37.2°C to -34.4°C) — the band of average annual extreme minimum temperatures that defines this zone (USDA ARS PHZM 2023)
- What that means: in an average year your coldest night lands somewhere in that 5°F window. Actual lows can drop colder in extreme winters; daytime highs are not bounded by this number.
- Found In: 10 US states, including Colorado, Alaska, Idaho and 7 more
- Growing Considerations: Upper Midwest and northern New England — cold-hardy fruit trees and root vegetables.
What Is Zone 3B?
USDA Hardiness Zone 3B is defined by an average annual extreme minimum temperature between -35°F and -30°F (-37.2°C to -34.4°C), according to the USDA ARS Plant Hardiness Zone Map 2023.
Coldest avg. low
-35°F
USDA PHZM 2023
Warmest avg. low
-30°F
USDA PHZM 2023
Coldest avg. low (°C)
-37.2°C
USDA PHZM 2023
States
10
Where Is Zone 3B Found?
Zone 3B appears across 10 states:
Plants That Thrive in Zone 3B
Plants well-adapted to the temperature range of this zone.
Apple
Garlic
Sugar Maple
Blueberry
Your Zone Is Just One Factor
Zone 3B covers 21 counties across 3 states, and their growing seasons are not the same. Lake County, Minnesota measures 137 frost-free days a year; Red Lake County, Minnesota measures 161 — a 24-day difference under the same winter low, before you get to soil drainage, summer heat, flood risk, or contamination proximity. Your Growable Ground report scores 1,112 plants against all of it for your specific address.
Measured across the 21 counties whose USDA PHZM centroid falls in Zone 3B — NOAA 1991–2020 Climate Normals, 28°F killing freeze. Median 151 days.
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Frequently Asked Questions
What plants grow in Zone 3B?
Upper Midwest and northern New England — cold-hardy fruit trees and root vegetables. Common plants that thrive include Apple, Garlic, Sugar Maple, Blueberry. Actual suitability depends on your parcel's soil, drainage, and microclimate.
What states have Zone 3B?
Zone 3B appears across 10 US states: Colorado, Alaska, Idaho, Maine, Minnesota, Montana, New Hampshire, North Dakota, Wisconsin, Wyoming.
What temperature is USDA Zone 3B?
USDA Hardiness Zone 3B is defined by an average annual extreme minimum temperature between -35°F and -30°F (-37.2°C to -34.4°C), per the USDA ARS Plant Hardiness Zone Map 2023.