Winterizing Your Pond

Posted by Aquatropic Staff on December 1, 2022

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Fall is certainly upon us in most of the cold weather areas of North America. When the leaves begin to fall, and your pond temps start to drop is the time to start thinking about how you are going to winterize your pond.

The first consideration when staring a long cold winter in the face is how to adapt your feeding regimen. As the temperature in your pond drops below the mid 60s Fahrenheit, most fish commonly seen in ponds will have a dramatic drop in metabolism and thus what and how much you feed your pond will need to change. Obviously the best way to decide when to make this change is to monitor your pond's temp more closely once night time temperatures start getting down to the 50s and below. When the actual pond temp reaches 65ish, you should reduce feeding to half your normal schedule and utilize a winter (lower protein) food. Once the pond temp reaches the low 50s, you should postpone feeding until next spring. If you live in an area where your pond will stay in this range all winter, you can keep feeding, but stay on the winter food and the less frequent regimen until your average pond temp comes back up into 60s again.

The next big consideration is dealing with all of the leaves that fall and blow into your pond. Leaves can be manually removed for those of you with cold tolerant arms and small ponds, but many pond keepers will use netting over the pond to prevent the leaves from entering in the first place until the vast majority of the leaves have fallen for the year. Once the leaves are done, it's important to remove the netting as most pond netting can't support a snow and ice load, and won't make it through the winter. As a side note, waiting until your pond is frozen will make your net basically impossible to remove. If you are late to the leaf prevention / removal process, and have a large amount of leaves already in the bottom of your pond, these need to be removed as soon as possible. As the leaves degrade they will steal valuable oxygen from the water. In addition, built up leaf litter makes an ideal habitat for lots of parasites and other unwanted guests. Clean the pond!

For those of you with plants, which in our experience is the vast majority of people who keep ponds, now is the time to do a fall cutback. Water lillies should be cut down to a couple inches above their crown, and most marginal plants (plants around waters edge) can be cut down to a few inches above the ground / water level. Plants that aren't zone appropriate, like most tropical plants will need to be removed and disposed of, or overwintered inside. If you are unsure about a specific plant's overwintering needs, a quick google search will give you a detailed process for each species. This is also a good time to split plants like lillies, and there is a bevy of tutorials online in regards to technique for doing so. Some plants like irises like being split in the summer and some like pickerel can be split whenever and seem undeterred by anything you throw that them!

You'll also need to ensure adequate oxygenation for your pond, as well as making some consideration for the protection of your fish. In regards to the oxygen, most northern pond keepers utilize an air diffuser or a circulation pump or both. Make sure these are suspended above the bottom of the pond; this helps promote circulation and prevents them from freezing to the bottom. Both these tools can help keep a small opening in the ice, which is important for gas exchange and keeping the pond healthy. If aeration alone isn't enough to maintain this opening, a floating de-icer may be required. The downside to having this air exchange is that it keeps a gateway open for winter predation, and with the plants mostly cut back, your fish will need some help hiding from predators. Increasing the amount of inert cover in the bottom of the pond with clay flowerpots and pvc tubes they can fit into is a good idea. Many pond keepers will also use a dark winter dye to help hide their fish from herons, raccoons, otters and anything else that wants some fresh seafood in the middle of winter.

The next consideration is for those of you who have a waterfall. In our experience, waterfalls are great through the winter as long as you live somewhere that doesn't freeze. They add water movement and oxygenation. For the rest of you, who have ponds where it does freeze, the water falls should be turned off. While it can be stunning to see the ice structures that your waterfall will make over the winter, these structures are unpredictable. They can easily form in a way where the water is directed away from the pond, leaving you with a ice rink in the yard, and an empty pond. If your waterfall pump is located in an area where it can freeze, it should be turned off to prevent damage, or removed completely.

Lastly, many people start keeping ponds when their fish outgrow their aquariums, which is reasonable, and makes for some really interesting pond fish. Be aware that many of the common aquarium fish are tropical in nature and so some research will be required to see what kind of temperatures they can deal with in the winter. Many pond keepers keep their more delicate species in a variety of containers in their garage or basement. We've even seen a pond keeper in Wisconsin keep Pacu happy in feeding troughs he got at a local feed store over the winter. Thinking outside the box here can open new doors as to what you could keep and where you can keep it!

So while winter is coming, pond season never really ends. A little bit of preventative maintenance now will go a long way toward seeing your pond develop and thrive for years to come! Check back here in march and we'll start talking about getting your pond in shape again for the coming summer!