How-To

Pond Winterization:

When winterizing your pond, you should consider the five following things:

Fish
Koi are such hardy fish, they can withstand a very broad range of temperatures, from freezing conditions to hot summers. This means the temperature of the water is the least of the pond owner’s worries.
Keeping the water circulating will benefit the fish year round. This helps to maintain beneficial levels of oxygen in the water and filters/releases out impurities in the water that occur during the breakdown process happening at the bottom of the pond.

As the temperature drops, the Koi will move towards the bottom of the pond, and will become more and more reluctant to feed, especially in temperatures below 50 degrees F. During the winter season the fish will go into a state of hibernation or dormancy where they will often times huddle together at the bottom. The earth acts as a natural insulator and thus it is warmer at the bottom than at the top. Their respiration and metabolism slows drastically to conserve body heat, which means that processing food is very difficult and a risky task. We recommend not feeding your fish when the temperature of the water gets below 50 degrees.

Plants
A lot of aquatic plants act like perennials in the landscape. They will die back when the temperature cools down, these plants you will want to prune. This pruning not only helps keep the area looking clean and manicured… but plays an important role in keeping the organics out of the pond.

Circulation
Keeping the water moving is a great way to help maintain a healthy environment. Moving water over a falls will increase and maintain adequate oxygen levels in the pond for the fish. It also helps to create a gas exchange thus preventing a buildup of toxins in the water that could occur if the water freezes over and there is no moving water. Watch for buildup of debris around the pump. This is true for ponds without a mechanical skimmer… you may have to clean out around the pump once a week or more depending upon your environment. Mechanical skimmers are much easier to maintain in relation to the pump… cleaning a high quality mechanical skimmer usually takes 5 minutes while the old style could take you hours.

It is beautiful when the water freezes over the pond and at the edges of the stream, and with an adequate pump size (~1500 to 2000 gal an hour) the static surface area of the water is broken and will not freeze all of the stream and waterfalls area. You need to be cautious however during times of extreme cold/freeze cycles… what happens is water will get locked up in ice thus effectively dropping the water level in the pond. If the level of water drops too low your pump could run out of water and cause damage to it. Ice along streams can create a diversion for upstream waters out of the system and thus reducing the water level as well. Supplementing the water supply might be necessary… but typically in the northwest this is not much of an issue. When it is cold here we often times will still get some rains that will make up for any water loss due to ice.

Winterizing supply lines
Auto-fill devices to the pond should be protected, shutoff and winterized. This will help reduce risk of damage that could occur to those lines, and they are not needed during this time of year.

Debris
You will want to make sure and do some policing around and in the pond during the final days of fall and into winter for branches, leaves, plants and general debris that have fallen into the pond. The trick with managing the pond environment really has to do with managing the nutrient load for that body of water. Keeping excess organics (leaves, needles, branches, plants) cleared out of the pond will help to keep down the dissolved organic load… thus reducing the overall available nutrient load. This extra care in the fall will help to make for an easier spring cleanout and startup of the pond.

Most ponds that are of good design will not need a lot of extra care during the winter months. They can be a great inspiration and beauty when the rest of the yard looks a bit blaaah. Water features should be low maintenance (with the right design) but they are not zero maintenance. A little thought and understanding of the water feature can go a long way to increasing the enjoyment and function of that feature!