USDA Maine Hardiness Zones: 3b, 4a, 4b, 5a, 5b, and 6a
Maine is known for its almost 3,500 miles of coastline. While Maine is a coastal state, it is not an extremely warm state. Maine is famous for its extremely cold and snowy winters.
During the summer months, Maine is generally considered mild. Because the summers are mild and warm, its climate is considered humid continental.
Don’t let the extremely cold winters fool you. Maine is a large producer of potatoes. Other crops, such as corn and oats, grow well in Maine’s six planting zones. Those planting zones are zones 3b, 4a, 4b, 5a, 5b. and 6a.
Maine Planting Zones- A Quick Overview
- The planting zones of Maine vary across the state. You may live in an area that’s considered 3b, but a mile away from your property may be planting zone 4a or 4b.
- If you live in the northern portion of the state, you will live in the 3b planting zone or 4a planting zone. The northern half of Somerset County is classified as the 4a planting zone.
- The middle portion of the state, including the lower half of Somerset County and Piscataquis County, is considered the 4b planting zone.
- Parts of Augusta falls into the 5b planting zone.
- The coastline near Brunswick is located in the 6a planting zone.
Using the Maine Growing Zones Map
Maine’s climate and planting zones vary depending on where you are in the state. Because the state is so varied, it’s imperative you refer to the USDA Plant Hardiness Zone Map. The USDA Plant Hardiness Zone Map, created in 2012, is a critical reference tool designed to help you determine the exact planting zone of your area.
Growers, planters, nurseries, and everyday gardeners use this handy reference tool to evaluate and choose plants that are best suited for each planting zone.
Access the USDA Plant Hardiness Zone Map to find your planting zone. You can click on the state of Maine and zoom into the general area of your location. Or enter your address and zip code to receive the most accurate information regarding your planting zone.
You will notice the map is color-coded by planting zone. Match the color of your planting zone with the legend on the side of the map.
Because Maine has six planting zones, it is essential that you also consider your garden’s micro-climate before planting vegetables or flowers. Factors such as slope, airflow, or soil types affect the microclimate.
The general area of your location may be considered 4a, but in reality, your site’s micro-climate may actually be a 3b planting zone. Temperature significantly affects the classification of planting zones. Check out your local weather data to help gauge your micro-climate.
Maine: It’s Not Always Cold Here
Although Maine’s climate is humid continental, Maine does not have a long summer growing season. The beginning of Maine’s growing season usually falls around mid-May. This is when you can expect the year’s last frost to fall.
The year’s first frost is generally around the middle of September. You can expect the growing season to end with the year’s first frost.
If you plan to plant a vegetable garden in mid-May, consider growing broccoli, cauliflower, or parsnips. These vegetables, along with beans, corn, and early potatoes, grow well in the planting zones of Maine.
O’Donal’s Nursery, located in Gorham, Maine, suggests planting passion flowers, lavender, and Mandevilla to brighten up your flower garden. Think about planting Balsam firs, red maples, or sugar maples to add to your landscape.