It's now time to put ponds to bed for several months. A few simple steps can save some slimy and potentially costly work in the spring.
If a pond is strictly decorative and you're not concerned with maintaining existing plant or animal life, you can just drain it, clean it and store the pump indoors. Check another task off the list. A more complicated pond, though, does require some work each fall.
Before using a leaf rake or narrow-tine pitchfork, Todd Anderson, of Windscapes Landscaping in Burnips recommends you clean out submerged plant debris such as string algae. If you live in a neighborhood or wooded area that has blowing leaves all through the winter, consider using a fine mesh net, such as bird netting, to cover the pond for the winter to keep additional leaves from collecting.
Now to the bottom line: saving yourself from costly mistakes. A basic scientific fact is water expands when it freezes. Simple as it may be, we often forget or underestimate the bone-cracking force that freezing water can have on objects such as pipes or filters. Steve Windemuller, the owner of Windscapes, recommends you winterize the pump and store it indoors, ensuring that moisture remaining in the pump will not freeze.
If your pond is home to a few beautiful koi fish, having to replace them in the event they don't survive the winter can be costly and heartbreaking. Anderson recommends you drain the pond slightly to accommodate the addition of water through rain and snowfall.
Keep a small portion of the pond from freezing over. Although fish metabolism slows significantly during the cold weather, you still need to allow oxygen to enter the water and carbon dioxide and other harmful gases to escape. Anderson suggests two main options to keep the water open. Cattle de-icers are floating rings that plug into an electrical source and are used to keep a water surface from freezing over.
A more energy-efficient option is a submersible bubbler pump, which can be found at home improvement stores. Place it in the pond, just under the water's surface.
Rebecca Finneran is a Michigan State University Extension Horticulture Educator, garden writer and lecturer.