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Preparing Your Pond for Winter

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Are your fish and plants ready for cold weather? Throughout the summer, debris builds up in your pond from falling leaves, fish waste, decaying plants, and algae. The excess organic matter will reduce water quality and stress both fish and plants during the winter months. It is important to properly prepare your pond for winter. The following proven techniques will keep your fish and plants healthy during the long winter months.

Why can’t I just let nature take care of my pond?

Water gardens we create look beautiful and sustain life because we follow nature’s rules. During the winter months, despite all outward appearances, the pond is active even when the water is cold or even frozen. Dead leaves, algae, insects and solid fish waste that have accumulated over the summer slowly break down during the winter months.

A build-up of leaves and other organic matter can cause an imbalance, reducing oxygen to dangerously low levels and releasing poisonous hydrogen sulfide. Use a net to remove dead leaves and excess sludge from the bottom. You should reduce sludge build-up with a bacterial “cleaning” product like PondCare, PondZyme, or EcoFix. These products contain bacteria that digest dead algae, plants, and sludge that accumulate in filters and at the bottom of the pond. They are completely safe and help keep water gardens clean. PondZyme and Ecofix continue to be effective even below 50°F in keeping you pond water clear.

While you’re stirring things up, you should change some of the water. Algae promoting nutrients, dissolved organic matter and natural acids build up in all water gardens. These substances can stress pond life and lower oxygen and pH levels. Partial water changes flush out these substances and improve water quality.

Change Your Pond Water

Change 50% of the water in your ponds in autumn. If a pond has a lot of suspended matter or the water is tinted yellow from dissolved organics, make two water changes a day apart. While pumping out the water, you will stir up the sludge. Pump out the sludge and old water at the same time! Remember to add PondCare Stress Coat to the pond before refilling it with tap water.

Stress Coat will condition the water and add a protective slime coat for the fish. If your tap water is treated with chloramine then add PondCare AMMO-LOCK®. Many pond enthusiasts add PondCare Pond Salt to replenish important electrolytes that aid the fish during the stressful winter months. Check the salt level with a PondCare Salt Level Test Kit and follow the directions on the package.

This may seem contradictory, but you want to leave a little bit of debris in the pond when preparing it for winter. Some water gardeners net out the fish, completely drain the water and scrub out the pond, refilling it with fresh water. Frogs, tadpoles, snails and microscopic pond life need to burrow down into the mud and leaves to survive the winter. Fish also hibernate on the bottom, settling in around a bed of leaves and mud.

Remove about 90% of the leaves and silt that have accumulated over the summer. Leave the rest as “bedding material.” You’ll be amazed at the diversity of pond life that emerges in spring. Keep in mind that tree leaves will continually fall into the pond as long as the water isn’t frozen. Cover your pond with plastic pond netting. This black plastic netting is almost invisible and prevents tree leaves and debris from getting into the pond. Entering the winter with a clean pond will help keep your pond, its plants and fish safe over the winter and give them a strong start in the spring.

Getting Fish Ready For Winter in Your Pond

The metabolism of koi and goldfish is controlled primarily by water temperature. As the water cools, pond fish require less protein in their diet. When koi and goldfish are fed high-protein food in cool water, the excess protein is excreted as ammonia from the gills. The bacteria that makes up the biological filter (and consume ammonia) also slow down in cooler water.

Improper seasonal feeding can lead to a build-up of toxic ammonia, which stresses fish and reduces their winter survivability. When the water temperature drops to approximately 65°F (18°C), start feeding your pond fish with PondCare Spring and Autumn Pond Food. This type of fish food is better suited for the dietary requirements of pond fish in cool water and won’t pollute the water with excess ammonia. Some water gardeners continue to feed their fish until they no longer come to the surface, but make sure you stop feeding pond fish when the water falls below 42°F (6°C).

Caring for aquatic pond plants

Long after the Impatiens have been pulled out, water gardeners are still hoping for that last lily bloom. For some reason, we want to squeeze every leaf, bud, and blossom out of our aquatic plants before winter. Unfortunately, cold weather often comes before we’ve trimmed the cattails or pruned the lilies.

Wait too long and all those beautiful leaves will fall off and rot in the water. Trim bog and marsh plants such as papyrus, taro, and cattails, before frost hits. Pull out the hardy water lilies and trim off all the leaves. Yes, even that last bud! Put all the potted plants into the deepest area of the pond to prevent freeze damage.

Performing these simple maintenance procedures ensures you that you have done everything you can to prepare your pond and fish for another season. It is highly recommended that the above maintenance takes place in the fall when fish are at their healthiest.

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