Winterizing Your Pond

For many parts of the country, it’s getting to be that time of year again. Time to start thinking about getting your fish and plants ready for old man winter…

Every year, as the weather gets colder and we start heading into winter, many of our customers ask us how to prepare their ponds for winter. Pond owners should be aware of several simple things to do in preparing their ponds for colder months.

Fish and plants need very different things in the winter, but can be kept in top condition for the following season if the appropriate steps are taken (see related articles).

Fish should be fed less, floating annuals should be thrown out, potted hardy plants should be cut down and moved to the bottom of the pond, filters should be cleaned & drained, and pumps shut off.

Another good practice that we recommend is to do a partial pond cleaning and water change. It’s not necessary to drain the pond completely, but we recommend draining 25% – 50% of the water and net out or remove as much organic debris as possible (IE: leaves, plants, etc.)

The reason for this is because rotting leaves, dead plant material, and other organic wastes will give off toxic gasses as they decay during the winter. This can be especially dangerous if the pond is allowed to freeze over.

A thick layer of ice can easily form over the pond in sub-freezing temperatures, which can prevent these gasses from escaping from the pond. If allowed to build up, your fish will suffer. The most likely result will be a weakened immune system, and a more vulnerable fish you will have come spring time.

Anything you can do to reduce stress on your fish prior to and during winter, will pay off handsomely in the Spring. Your fish will be much more vibrant and healthy.

Another important reason not to let your pond ice-over is because the oxygen levels in the pond water can drop to dangerous levels. By keeping the pond surface from freezing over, or by at least keeping a 2′ – 3′ hole in the ice, you can eliminate or greatly reduce these dangers.

Oxygen levels should be maintained during winter if at all possible. If you have a standard aquarium air pump – plug it in outside and let it run all winter.

We also recommend maintaining your salt levels during winter. This keeps your fish’s slime coat strong, and immune systems strong all winter long!

Wildlife in Winter Ponds

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 mud and leaves to survive the winter.

Fish also hibernate on the bottom, settling in around a bed of leaves and mud. I 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 blow into the pond as long as the water isn’t frozen. I recommend covering the pond with bird netting.

This black plastic netting is almost invisible and prevents tree leaves and debris from getting into the pond.