Snow cover and prolonged below zero temperatures play a vital role in the health of plants and soil.
Changing Temperatures
Long cold spells can kill off garden pests that aren’t built to survive a cold winter. For example, invasive Japanese beetles are less likely to survive and damage our garden plants. During a warmer winter, their chances of survival are higher. Bacteria-carrying insects, like ticks, can move further north because of warmer winter temperatures as well. Dormant plants and hibernating beneficial insects are more stressed and susceptible to diseases and to these pests, and others, when temperatures warm–especially if the temperatures jump quickly between freezing and thawing.
This repeated freezing and thawing, along with more winter rain and wet soil, creates pressure in the ground and pushes soil upwards. This “frost-heave” can damage tender plant roots or even lift plants (especially newly planted ones) up and out of the ground. In our region, below-zero temperatures are needed to improve soil structure and drainage and to prepare seeds for germination in the spring.
More Rain and Less Snow Cover
A thick blanket of snow is nature’s best winter insulation, protecting soil, plants and beneficial insects. With less snow cover, soil can dry out and blow away, and plants and insects become more exposed to sudden temperature drops. When soil is frozen and precipitation falls as rain instead of snow, the soil can’t absorb the water, which can lead to flooding.
Protect the Plants
To help reduce the negative impacts of climate change on plants through the winter, the best thing you can do is maintain a protective five to eight centimetre layer of leaves and/or mulch over soil and around trees.
A version of this article was originally published in the February 2023 edition of The Garden Post.
Discover the Natural World Around You
Ever wonder what plant you’re looking at or what bird is singing? Late winter is a great time to start discovering the natural world around you. It’s easy with the following tools:
- iNaturalist is a nonprofit social network of naturalists, citizen scientists, and biologists that works to identify, map and share observations of the natural world around you.
- I-Tree is a powerful tool that helps you quantify the environmental, economic and social benefits of trees on your property.
- Merlin will amaze you! It identifies bird chirps, songs and calls and gives you information about each species.
- Bird migration can be complex! BirdCast’s real-time nocturnal migration maps show the routes and traffic rates of birds travelling up from the United States. Migration alerts are available for Toronto between March 1 and June 15, 2025.
- Learn how to feed and identify birds on your property at Feeder Watch. A little knowledge keeps the birds healthy and critters at bay.
Spring Into Action Against Invasive Species
Invasive species are estimated to cost Ontario $50.8 million per year in management. Help stop the spread by learning to recognize and remove them on your property:
- EDDMapS report and identify invasive species in Ontario
- Invasive Species Centre Community Science Program
- Grow Me Instead guides
Book Your Nature at Work Event Now
Greening Corporate Grounds’ Nature at Work program engages employees in nature-based team-building activities on your property. Build morale, foster stewardship, and demonstrate your organization’s commitment to the community and the environment. Learn more: cvc.ca/NatureAtWork