Winter care for backyard ponds

Olivia Canfield
Carroll County Master Gardener Program

As temperatures continue to fall and snow is in the forecast, many of us with backyard ponds begin to worry about our friends under the water's surface. It's the snow, cold and ice that we need to prepare our fish and plants for, and with a few simple steps you can ensure the survival and health of your pond throughout the winter months. If you haven't already, make sure that all of your plants have been cut back and put in the deepest part of your pond so their foliage does not continue to decompose causing gases to build up. All fish feedings should stop and not resume again until water temperatures reach 50 F. After all the fish and plants have been put to bed for the winter, most people wonder what is the best thing to do…keep their pond running all winter, or shut it down for the season. Either one will work fine as long as you take the right precautions.

If you choose to shut down your pond, remove your pump, clean it, place it in a bucket of water, and store it where it is protected from freezing. Place a small re-circulating pump (at least 150 gph) in the pond on a shelf or low water-level area to agitate the surface to provide oxygenating water and to keep a hole in the ice where toxic gases can escape when the pond is iced over. If your pond is small, you may be able to use your existing pump without any fountain or hose attachments. You may need to supplement your pump with a low voltage heater, when temperatures become extremely cold. This type of heater runs only enough to maintain a small hole in the ice. (Be wise, make sure what wattage your heater runs on, some heaters on the market are high wattage and expensive to run!) Floating heaters do not provide important oxygen to your fish, so they shouldn't be used alone.

When you decide to keep the pond running all winter, you're almost guaranteed a beautiful ice display! However, you'll need to watch out for slow moving streams where ice dams can form, which can re-direct water out of your pond! A small pump or heater may still be necessary to keep a hole in the pond's surface. You can even use a hot pan of water to melt a spot in the ice periodically if you are vigilant about checking! Do not attempt to break the ice, as shock waves can stun or even kill your fish. If an external pump and filter system is used, make sure to drain and store them, or take precaution to prevent freezing.

Many people battle with heron in the winter too, so if you had problems with them in the spring and summer, leave your pond cover nets or other deterrents, such as artificial heron statues, in place during these cold months too. They are more likely to attack when the fish are slower and have little plant cover to hide.

Finally, when old man winter arrives and the snow is drifting outside your door and blanketing your water garden, relax in the warmth of the indoors and admire from a distance, believing that spring, along with your beautiful water lily, is right around the corner.

Read other articles on gardening techniques

Read other winter related gardening articles

Read other articles on Winter and your garden