Wintering Your Water Garden Plants & Fish

As the days grow shorter and the temperature starts to fall, pond owners will need to think about shutting down their ponds for the season, and wintering their plants and fish. The health of your fall pond will help to provide your fish with a healthy environment, whether you maintain them in the pond itself or winterize them in an indoor aquarium or tank.

Below are a few tasks that are essential to get your pond ready for the long winter and help ensure a healthy pond next spring.

Plant Care in Winter

Hardy Water Lilies are easily wintered, just cut back the yellowing leaves and submerge the lilies to a depth where they will not freeze, usually 2 feet is sufficient.

Lotus can be wintered in the same manner as water lilies. Lotus will survive the winter as long as the tubers do not freeze solid.

Fall Pond Prep for Fish

Goldfish and koi are very hardy fishes; they can survive water temperatures as low as 0°C, which means they can survive in the pond during the winter as long as it doesn’t freeze solid and they have adequate water quality and oxygen. To help ensure healthy fish in the spring, follow these steps:

  1. Begin feeding a Cold Water Fall Fish Food once the water temperature falls below 18 °C / 65 °F. Start by mixing a bit of the Fall Food with their regular summer food, and then gradually increase the amount as the temperature decreases. Once the water temperature falls below 15 °C / 59 °F you should only feed a cold water food. Gradually reduce the amount of food that you feed as the temperature drops. Stop feeding once the water temperature consistently remains below 9 °C  / 48 °F. It is important not to feed fish below this temperature, their metabolism is so slow that their digestive system basically shuts down and does not process food.  At low temperatures, food can become lodged in their gut for long periods of time causing serious problems. Always use a Pond Thermometer to check the water temperature.
  2. Remove tree and plant leaves from the pond. Leaves and other organic matter will continue to break down through the winter months causing poor water quality (elevated ammonia and nitrite) and low oxygen levels in the pond. The easiest way to do this is to prevent leaves from getting into the pond by covering the pond and waterfall with Pond Netting. Also remember to remove any tropical plants like water lettuce or water hyacinths and trim any dead leaves from water lilies or marginal plants.
  3. Remove sludge and debris from the bottom of the pond. Use a fine mesh Net or a Pond Vacuum to keep the bottom clean.
  4. Maintaining a hole in the ice is essential to fish survival during the winter. An opening in the ice allows oxygen into the pond and noxious gasses such as carbon dioxide out of the pond. A Pond Heater / De-Icer is generally the best choice for keeping a hole open through the ice. You could also bring fish indoors before the water temperature drops to 10°C (50°F) and place them in an aquarium or tank. Keep the water relatively cool and feed moderately. Filtration and oxygenation is needed.
  5. Adding Pond Salt is also beneficial to fish. It will stimulate mucous slime coat production, make osmoregulation easier and also reduce the effect of nitrite toxicity. A concentration between 0.1 and 0.25% is ideal (approximately 1 lb to 2 lb of salt per 100 gallons of pond water).


Marginal Plants

Hardy plants can survive even if they freeze solid, as long as they stay in the pond. These plants include most irises, sweet flag, rushes, reeds grasses hibiscus and horsetails. They can be submerged to deeper depths, but they will also do well if left near the surface.

Marginally Hardy plants can survive the winter cold, but will die if their crown becomes frozen. These plants include: pickerel plant, hardy water canna, parrot feather, water clover, water parsley and cardinal flower. To winter these plants submerge them below the ice line.

Tropical Plants will not survive the winter outdoors. But many of these plants will grow easily in the house if brought inside before the first frost, placed in a container of water and given plenty of light. Plants such as Umbrella palm, papyrus, cannas, taro, bog lily, etc. can be brought inside and make great house plants

Winter Pump Care

In most cases it is best to remove your pumps from the pond, clean it thoroughly and store it for winter. If you have a direct drive style pump (not a magnetic drive or asynchronous pump) then it should be stored in water and protected from freezing. This helps to keep the seals moist. If you have a magnetic drive or asynchronous pump they can be stored anywhere dry.

Filters & Ultraviolet Lights

Waterfall style filters can be left in place but should be drained. It is best to remove the filter pads and bio-media, clean them thoroughly and store somewhere dry.

Pressurized filters should be drained and stored inside somewhere dry. It is best to remove the filter pads and bio-media, clean them thoroughly let them dry and store them back inside the filter.

UV lights should be disconnected, cleaned and stored somewhere safe where there is no chance of them falling and breaking the quartz sleeve and bulb.


Need some more help? Check our event schedule for upcoming seminars that will provide both beginners and seasoned pond owners with the knowledge to make the shutdown process as easy as possible.