By Jenevra Wetmore

The new 2023 Plant Hardiness Zone Map. Image credit: USDA

If you are a farmer or gardener, then you know how important the USDA (United States Department of Agriculture) plant hardiness zones are. These zones are based on the lowest annual winter temperature in your area and correspond to which plants will thrive in your location. For example, a person using a map of hardiness zones will know not to plant a palm or coconut tree in Vermont because it will be too cold to survive. This past December, hardiness zones made the news in Vermont because, for the first time since 2012, the map changed. These changes are significant and reflect a warming climate that will affect how Vermonters garden and farm in the future.

Vermont has shifted into warmer hardiness zones. Our state is mostly in zone 4 and 5 of the hardiness map, with a and b sections within those zones. Unlike the 1990 or 2012 map, the new 2023 map shows zone 5b (with low temperatures of -15 to -10 degrees Fahrenheit) moving into the southeast and southwest of the state, with a significant presence in Bennington, Windham, and Windsor counties. In the 1990 map this zone was virtually absent from the state. A small section of Woodstock and West Windsor is even in zone 6a (-10 to -5 Fahrenheit), which was previously unheard of in Vermont. Meanwhile in Northern Vermont, the territory of the coldest zone, 3b (-35 degrees to -30 degrees Fahrenheit), has disappeared from the map, and has been replaced replaced by zone 4a (-30 to -25 °F) in the area encompassing Saint Albans, Swanton, and Lowell.

This new map from the USDA confirms what those of us gardening in Vermont already knew– warmer weather is here to stay. Gardeners and farmers have begun to plant crops in anticipation of warmer climate, such as paw paws and peaches, which thrive in climates that are slightly warmer than ours (haven’t heard of a pawpaw? These fruits are native to the eastern United States with a flavor compared to banana, mango, and pineapple). The lack of hard frosts in some parts of Vermont may make it easier to grow grapes used for wine making in the coming years as well.

Changing hardiness zones are a sign of what is to come, and the effects of climate change will not be nearly as predictable or straightforward as a map may make it seem. We all experienced the devastating floods of this summer and fall, which destroyed many crops and were only a precursor to a historically wet growing season. This is what climate change looks like on the ground, experienced by real people who are growing food to feed themselves and our community. The Northeast Organic Farming Association of VT (NOFA) awarded over $1.6 million in Farmer Emergency Grants in 2023 and will be holding $100,000 in savings for the next disaster. This is how we as gardeners and farmers need to think now; we must be prepared for the next obstacle and think creatively about how to become more resilient.

Thankfully, there are tangible actions we can take in our gardens to help the planet and become more resilient. Improving soil quality by practicing no dig or minimal disturbance gardening will create healthier soils that can hold more water and prevent runoff and nutrient loss. Other actions include: planting native species to encourage pollinators, composting food scraps and using them as fertilizer, mulching annual and perennial beds, and following organic gardening practices. The new USDA map tells us what we already knew– climate change is here. It is up to us to make the best decisions possible with that knowledge.

What You Can Do:

• Explore the USDA’s new Plant Hardiness Zonemap: https://planthardiness.ars.usda.gov/

• Plant natives! You can search Audubon’s database to see what plants are native to our area: www.audubon.org/native-plants

• Avoid invasive plants, and remove what you can. View a list of invasives in VT at https://www.vtinvasives.org/

• Read “The Complete Guide to No-Dig Gardening” by Charlie Nardozzi, or other books on no till and minimal disturbance gardening and farming