Winter visits your backyard pond

Pond winter management helps to maintain a healthier ecosystem for your plants and fish.

Ponds can freeze over in the winter and be just fine. However, if you have a small pond or a garden pond simple maintenance steps can prevent springtime disasters, such as dead frogs and fish. Water gardens especially require winterization in northern climates like Michigan. Hopefully you have already removed dead decaying debris and non-winter hardy plants from your ponds. This practice will reduce the nutrient load in the water from decomposition. Decomposing plants can reduce oxygen levels which can stress or kill the aquatic residents of your pond.

One of the things Michigan State University Extension suggests to do is to manage your plants. Cut back the vegetation of those hardy plants that will be overwintering in the pond. Other fast growing plants should also be thinned. Move any plants that are in pots on the pond shelves deeper into the pond to protect them from freezing. Once seasonal plants have been removed from your water garden discard them responsibly. Never discard water plants or animals by putting them into other water bodies. If the plants are invasive aggressive growers or you have snails do not compost your plants. If you did winterize before freezing temperatures hit, plan to do it right away after the ice melts. It is still beneficial in managing nutrients.

Stop feeding the fish when water temperatures reach 45 degrees Fahrenheit. Even if the fish appear active they are entering a dormant state and will not be able to adequately process any food given to them. Keep at least 10 percent of the surface of your pond open for gas exchange. If you have a large pond and use it for winter sports, allowing it to freeze over completely you will need to remove fountains, turning off or your pumps and filters. Small ponds may need assistance to ensure adequate gas exchange with the atmosphere through maintaining a hole in the ice.

If you are using machines for this purpose, then heaters, aerators, and pumps should be set up higher in the water on a platform or shelf of the pond to allow the water temperatures to stratify. This reduces stress on the fish from water temperature fluctuations. Continue to monitoring your pond to ensure that water levels and pH remain stable through the winter. If you have removed all of your plants and fish in smaller ponds and fountains drain and cover the pond as needed to maintain safety.

If you or your lake association is interested in learning more about invasive aquatic invasive species, watercraft checkpoints education or in a volunteer training to educate boaters at local public launches contact Beth Clawson at For more information about Clean Boats Clean Waters Aquatic Invasive Species program or other water quality concerns contact Michigan State University Extension. Water Quality educators are working across Michigan to provide natural resources water quality educational programming and assistance. You can contact an educator through MSU Extension’s “Find an Expert” search tool using the keywords “water quality.”

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