As winter draws near, it’s important to prepare your backyard pond or water garden for the cold weather ahead. Follow these guidelines for winterizing your pond to keep your fish and water plants healthy during the cold winter months.

Clean and Cover - Decaying leaves and plants produce gases that are harmful to the fish and the pond’s ecosystem if left in the water.

    • Use a net or vacuum pond cleaner to remove any fallen leaves and dead foliage that has entered the pond.
    • Cut back dead leaves and branches from surrounding pond plants so that they do not hang over the pond.
    • Cover the entire pond with netting to prevent additional leaves and debris from falling into the pond.

    • (Note: Once all the leaves have fallen, clean and remove the pond netting before the snow arrives. Snow and ice can accumulate on the netting and cause it to collapse.)

      Change the Water - Perform a 30- to 50-percent water change before the water temperature drops below 60 degrees F to remove contaminants and help maintain pleasant water conditions throughout the winter.

    • Use a de-chlorinator and neutralizer to remove chlorine in the tap water when adding it to the pond since chlorine and chloramines are poisonous to fish.
    • Make sure there is no more than a five-degree difference in the temperature of the pond water and the water from the hose as a severe change in temperature is stressful for fish and can cause disease.
    • Add pond salt (one pound per 100 gallons) to help fish restore their slime coat and boost their immune system.
    • Add cold water bacteria to reduce buildup, keep the water quality healthy for the fish, and condition the pond for startup in the spring.
    • Test the water and O2 level to make sure everything is in good balance.

Modify Fish Feeding - As water temperatures plummet, fish metabolism slows down and they require less food.

    • Start feeding your fish food with a wheat germ base when the water temperature drops to 60 degrees F. (Wheat germ is easier for the fish to digest at low temperatures than protein.)
    • As the temperature continues to dip below 60 degrees, feed your fish only two or three times a week.
    • Stop feeding your fish altogether once the water temperature reaches an average of 45 degrees F. (Fish are no longer able to digest food at this temperature.)

    • (Note: In order to overwinter fish, the deepest part of your pond must be below the local freezing line.)
      Check with your nearest pet store for additional information on keeping your fish safe over winter.

      Protect Your Plants
      - Fall is the perfect time to divide and repot your water plants because the mild temperatures give the plants time to heal their root systems before the chilly weather arrives.

    • Remove or bring tropical plants inside when the daily temperature drops below 60 degrees F. Many tropical plants can overwinter indoors with a large container of water and bright light. Floating plants, such as water hyacinth and water lettuce, should be discarded.
    • When temperatures reach 50 degrees F and before the first hard freeze, trim winter hardy plants (such as water lily and lotus) and then lower to the bottom of the pond.
    • Cut back marginal and bog plants and submerge them below the freezing line.
    • In very cold climates, such as the northeast, insulate bog plants with straw or commercial insulation material.

Close Up the Pond
- Depending on the climate in your region, you may or may not need to shut down your pond equipment in the winter.

    • If you live in an area with warm or mild winters, you can keep your pond pump running to prevent the pond surface from freezing. (Note: You will need to monitor the water level and stay aware of ice formations and weather changes so that water does not freeze in the pipes.)
    • In colder climates, shut down and remove the pump, filter, and UV sterilizers when the temperature drops below 40 degrees F.
    • Drain water out of the plumbing to prevent standing water from freezing and expanding, which can crack the pipes.
    • Clean all of the equipment according to manufacturers’ directions.
    • Store the filter and UV sterilizer in a warm, dry place.
    • Keep submersible pumps in a bucket of water to prevent the seals from drying out and place in a frost-free location.

    • Install Winter Equipment
      - If you have fish, you need to oxygenate the water and keep an opening in the ice so that toxic gases do not get trapped and kill the fish.

    • Place a small air pump or bubbler on the top shelf of the pond. The agitation from the pump will provide oxygen and help keep a hole in the ice when the pond’s surface starts to freeze.
    • Add a floating pond heater or de-icer if you experience temperatures below 10 degrees F for extensive periods as a small air pump will not be enough to maintain an opening in extremely cold temperatures.

    • IMPORTANT NOTE: Never try to physically break the ice if your pond freezes over. The shock waves can seriously damage or kill the fish. Instead, place a pot of hot water on the ice to gently melt a hole.

      Photos courtesy of Aquascape, Inc.