Winterizing vs Emptying the Pond
If this is your first year as a new pond owner, you may have no idea what to do with your water feature in winter. Many owners of small backyard and fishponds assume they should drain and empty the pond entirely over the winter to protect it from freezing. Unless you own a very small pond of just a few dozen gallons or live in the coldest environment, this is likely a waste of time and energy. In almost all but the very coldest areas, winterizing a pond correctly and installing some extra equipment to control ice cover is all that’s needed to keep fish alive. Find out why you don’t want to empty the pond unless it’s absolutely necessary.
Residual Water Collection
Water will continue to gather in the pond over the winter no matter what you do to drain and cover it. This is why most people that are concerned about a small, above-ground, water feature will bring it indoors when freezing is possible to keep snow and rain out. Many first-time pond owners spend hours meticulously emptying and covering their pond for the season just to find the cover pushed down under the weight of accumulated water. If a pond is designed correctly, to capture local rainwater flow, it’s going to naturally refill even during a relatively dry winter. Keeping it filled and winterized from the start is a better way to prevent ice damage. When there are only a few inches of water accumulated in the pond, it’s much more likely to freeze solid and crack the liner or kill sensitive plants.
Complete vs Cover Freezing
The one time it is recommended that you drain the pond completely is when you’re concerned about all of the water freezing solid. This is rare, unless you have a small pond with a low depth, and you live in a very cold climate. It generally takes temperatures below 10 degrees F overnight to freeze water that’s more than six to eight inches thick. Koi enthusiasts recommend having a minimum depth of two to three feet to ensure that ice forms on the surface but not throughout the rest of the water. If a pond freezes solid, fish and plants will die, and the expansion of the ice also damages the liner. Drain the pond and keep a pump handy to remove any substantial water collection over the winter if temperatures will get low enough to solidly freeze all the water solid.
Damage to the Liner
Draining the pond can actually damage the liner instead of protecting it in areas where the water is unlikely to freeze solid. Empty ponds are exposed to much more direct sunlight, accelerating damage from UV rays. All types of liners are susceptible to damage from the sun eventually, so keeping them covered with sand and a layer of water is the best way to protect them. If the water isn’t freezing at the bottom of the pond, flexible liner materials should be fine without damage. Rigid pond liners have trouble with winter conditions regardless of how you winterize them, so using a flexible liner material from BTL Liners is a good way to protect your ponds in the first place. Concrete lined ponds are the one exception. Most concrete lined ponds should be drained in the winter, especially if they’re smaller than a few thousand gallons, to protect the lining material. Concrete is very prone to cracking in the winter due to the expansion of freezing water, so it’s not an ideal pond lining material in cold climates.
Partial Drain for Cleaning and Repairs
While it’s not usually necessary to completely drain a pond in the winter, a partial drain is recommended to help you access the deepest parts. This allows you to clean out muck and slime, rearrange any rocks or decorative features that have moved, and repair any damage to liners or equipment. If you need to remove temperature sensitive fish or plants, draining the water a little makes it easier to see and catch them all. Don’t leave the pond partially drained over the winter, especially if there are fish and plants still in it, since this makes it more likely to ice over or freeze solid. Always top up the pond after cleaning so it has the extra depth to retain an ice-free zone.
Protecting Fish and Plants
Winterizing a pond that contains fish and plants generally means adding equipment to keep the surface from completely covering with ice. For many species, that is all that’s needed to help them survive the winter. Koi and carp are a little more sensitive to temperature and generally require supplemental heating to keep the water above 45- or 50-degrees F. If that’s going to cost too much for the entire winter, bringing the fish and plants inside is generally the best choice. Even if you remove your fish, there’s no need to do the extra work of draining the pond afterward. You can test and balance the water faster in the spring if you leave it in place over the winter. Important bacterial colonies will go dormant but remain in place, ready to go back into action in the spring when the fish return.
Pumping Equipment
Even ponds with no particular fish or plants to protect need winterizing to keep the pumping and aeration equipment from being damaged. If there’s no fish in the pond over the winter, turn off the equipment and drain it thoroughly. Change and clean any filters to ensure there’s no waste that could freeze in the units. Any parts that protrude above the surface of the water, such as aerator tubes or fountain sprayers, should be removed so that ice forming around them won’t cause damage. Ponds that stay stocked with fish through the winter rarely need pumps or aerators running either, so shut them down as well. If temperatures hover around 40 to 50 degrees F most days and rarely dip below freezing, you may want to continue running the equipment and only shut it down and drain it for freezing nights to prevent damage.
Now you know why it’s easier just to commit to winterizing the pond rather than trying to drain it each year. A pond is a living ecosystem, no matter how small, so it works best when allowed to go through the seasons naturally. This encourages more stable bacterial colonies for better water quality. You’ll find yourself spending less on conditioning and water testing, especially for sensitive fish like koi, after switching to a system that allows you to leave the pond filled over the winter. Even if you do end up removing sensitive fish and plants for the winter, try to keep the pond filled rather than draining it completely.
