Stack spent part of her day on Wednesday studying the new map and how it will affect Mainers. She was impressed with its level of detail and specific growing boundaries.
“Now, we can use this map to say where a particular plant can be grown,” Stack said. “That helps a gardener to say, ‘OK this plant is only hardy in a certain zone. I shouldn’t consider that for my garden.’”
Stack said the challenge for gardeners will be deciding whether to grow a plant or even a tree that might be borderline in terms of the zone it can survive in.
Stack said Maine gardeners might try to grow more varieties of rhododendron, a flowering woody shrub.
Amatuer gardener Anne Hagstrom of Yarmouth, who was shopping for houseplants at Skillins in Falmouth on Saturday, said she wants to experiment with plants she wouldn’t have tried before in her community garden plot this summer.
“But at the same time, I am wishing this was not the result of climate change,” Hagstrom said.
Seth Kroeck, who has been farming at Crystal Spring Farm off Pleasant Hill Road in Brunswick for nine years, said the new map won’t really affect his work. But he does agree that the growing season has been getting longer and warmer.
“Our frost dates are pushing back in both directions,” said Kroeck.
Two years ago, Kroeck said, he started turning ground in early March and last year the first killer frost didn’t arrive until late October. He said it feels as if the summers are getting warmer, making for a long and productive growing season.
“As a professional grower, the map doesn’t have a great impact on me, but it should help some of the new gardeners decide what to grow,” he said.
Kroeck is already thinking about the upcoming growing season. Seed catalogs started arriving this month.
“It’s a good time to curl up next to the wood stove with a seed catalog,” he said.
Richard Brozozowski, a University of Maine cooperative extension educator from Falmouth, teaches master gardener classes and said the new map does open the door for gardeners to try new varieties.
“Gardeners in Maine have tried growing everything, from peanuts and figs to sweet potatoes and kiwi,” he said. “They pushed the envelope.”
Brozozowski said peaches, grapes and okra might be able to thrive in Maine.
He suggested gardeners keep an eye on their property and watch where the snow melts first. He said warm pockets of land are good places to start a garden.
Tom Settlemire, retired from a career of more than 35 years as a biology professor at Bowdoin College, gardens and raises sheep in Yarmouth.
Settlemire is excited about the new map because it shows that ryegrass might grow in Maine. Ryegrass is a high-energy, high-protein grass that cattle and sheep graze on. It is grown extensively in places such as Australia and New Zealand.
“The problem has been that our cold winters freeze it out,” he said.
But if ryegrass could be grown here, it could have a positive impact on the cattle and sheep industry.
Not everyone is excited by the USDA’s new zone configurations.
Jeffrey O’Donal, who owns O’Donal’s Nursery on the Gorham/Scarborough town line, said the new map did not contain any surprises. He doubts that gardeners in Maine will start to grow plant species that might not otherwise have thrived here.
“In my opinion, none,” O’Donal said. “The real proof will be in the pudding. If you plant a plant and it dies, it doesn’t matter what the map says.”
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What’s Your Zone?
The USDA has issued the first update to the USDA Plant Hardiness Zone Map since 1990.
There are some significant changes, including portions of coastal Maine now considered Zone 6, which is comparable to living in New Jersey in the 1990 map. Comparable for temperatures, that is.
To the uninitiated, the zone map is a quick way to determine whether that posie you bought on impulse would survive a Maine winter. But not just any Maine winter. If you live in Aroostook County, that plant labeled Zone 5 likely will succumb to the cold, while if you live in, say, Bar Harbor, the plant will likely be OK since Bar Harbor is now considered Zone 6A.
As for Aroostook County, the shift has been warmer, too, with the 1990 Zone 3b designation now mostly changed to the 4a rating.
Meaning Maine is warmer than it used to be. And the state is not alone, for the USDA has added Zones 12 and 13 to the map. That means the lowest average minimum temperature in those areas was either 50-60 degrees (Zone 12) or 60-70 degrees (Zone 13).
Granted, those places aren’t in Maine, but it is a sign of a warmer world.
Here’s how the mapping works. Each zone is a 10-degree Fahrenheit range. And then each zone is further split into 5-degree bands A and B, with B being the warmer of the two.
According to the USDA announcement, “Plant hardiness zone designations represent the average annual extreme minimum temperatures at a given location during a particular time period. They do not reflect the coldest it has ever been or ever will be at a specific location, but simply the average lowest winter temperature for the location over a specified time.”
The USDA explains the general trend in the temperature shift: “Compared to the 1990 version, zone boundaries in this edition of the map have shifted in many areas. The new map is generally one 5-degree Fahrenheit half-zone warmer than the previous map throughout much of the United States. This is mostly a result of using temperature data from a longer and more recent time period; the new map uses data measured at weather stations during the 30-year period 1976-2005. In contrast, the 1990 map was based on temperature data from only a 13-year period of 1974-1986.”
But there were also other influences in the changes. First, more “sophisticated methods” for calculating between established weather stations were employed. The USDA wrote that these “include algorithms that considered for the first time such factors as changes in elevation, nearness to large bodies of water, and position on the terrain, such as valley bottoms and ridge tops.”
Plus, there are more weather stations providing more temperature data.
With all that said, how do you use the zone map?
With a grain of salt.
Since these are averages based on data from weather stations that may not even be located in your vicinity and from formulas based on elevation and so forth, these zones are not 100 percent accurate. An average also means there was a higher number and a lower, and it’s the lower number you need to worry about.
Zone maps are helpful in getting you in the ballpark, but it is important to be aware of the microclimate in your area. Plants growing against the foundation of your house have a warmer microclimate than a spot on top of an open hilly area.
The USDA release does address this with a sage piece of advice: “If your hardiness zone has changed in this edition of the USDA Plant Hardiness Zone Map (PHZM), it does not mean you should start pulling plants out of your garden or change what you are growing. What is thriving in your yard will most likely continue to thrive.”
The agency redeems itself somewhat with this comment: “You also could have pockets within your garden that are warmer or cooler than the general zone for your area or for the rest of your yard, such as a sheltered area in front of a south-facing wall or a low spot where cold air pools first. No hardiness zone map can take the place of the detailed knowledge that gardeners pick up about their own gardens through hands-on experience.”
And that’s the point.
Who uses the zone maps?
From the USDA: While about 80 million American gardeners, as well as those who grow and breed plants, are the largest users of the USDA Plant Hardiness Zone Map, many others need this hardiness zone information. For example, the USDA Risk Management Agency uses the USDA plant hardiness zone designations to set some crop insurance standards. Scientists use the plant hardiness zones as a data layer in many research models such as modeling the spread of exotic weeds and insects.
Maine Planting Zones – USDA Map Of Maine Growing Zones
Information On Maine Hardiness Zones
The map on this page is the USDA map of planting zones for Maine. This map will help you to find your USDA Maine hardiness zone. If you live in Maine, you live in one of these hardiness zones.
To use this USDA Maine hardiness zone map all you need to do is find where you live on the and match the color of that area of that map to the colors on the legend to the right. This will tell you what planting zone in Maine you live in.
The USDA Maine map above is based on the updated 2012 version of the USDA hardiness map. The USDA decided to update their hardiness zone map in 2012 to better reflect the changes in climate that had occurred over the past several decades. The USDA had found that previously identified hardiness zones in Maine had shifted. This map shows where the new growing zones in Maine are.
Understanding what USDA Maine planting zone you live in is important to how well your garden will do. Knowing your zone allows you to choose plants that will survive the winter. If you try to grow plants that are not appropriate to your zone, the plants you grow will die.
Plants that are appropriate ones for the Maine hardiness zone you live in can be found at your local plant nurseries or stores. The perennials they carry will be clearly marked with the zone that they are suitable for. You can plant any perennial that is marked for your growing zone or lower