Use this article to help decide if, when, and how you should winterize your pond to ensure a successful opening of your pond in the spring.
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Table of Contents
- To Winterize Your Pond or Shut it Down?
- Recommendations for Warm to Moderate Temperatures
- Recommendations for Moderate to Extreme Cold
- Caring for Koi & Other Fish
- Additional Reading
Fall brings with it colorful leaves, sweaters and the start of the holiday season, but it also brings a whole host of problems for your pond, its plants and the aquatic animals that call it home.
With a little planning and preparation, you can make sure your pond—and its flora and fauna—makes it through winter safe and sound.
In this article, you’ll find an overview of what you need to know about preparing your pond for winter to ensure a successful opening of your pond in the spring.
To Winterize Your Pond or Shut it Down?
During the summer months, you can usually sit back and enjoy your pond with minimal maintenance. Once the weather turns cooler, however, you’ll need to consider your pond’s aesthetics, water chemistry, fish health and a variety of other factors, such as the effects of rainfall expected in your area.
Essentially, you have two options in the winter: take the proper steps to protect the pond or shut it down for the winter. Which option is best for you depends on a few factors. First and foremost, you must identify your specific climate type.
Warm to Moderate Temperatures
(Not likely to consistently fall below 50 degrees Fahrenheit)
Even though you most likely won’t have to deal with frozen water, you’ll still need to be aware of a few seasonal changes that can affect your pond. First and foremost, cut back dead and dying foliage as the temperature drops to keep your pond clear of debris.
If you aren’t careful, falling leaves and debris can accumulate in your water and this decaying plant matter can alter the water chemistry and harm fish as well as create a recipe for a spring algae bloom.
If you already have leaves in your pond, we recommend a long-handled pond or pool cleaner to remove leaves, or better yet – consider installing a pond net to prevent them from getting into your pond in the first place!
Installing a Pond Net
- Measure the size of your pond. This is the size of netting you need, but leave a few feet of extra length in all directions so that you can easily secure the net to the ground.
- Place beach balls or other floating objects in the pond. This will help support the netting so it doesn’t become heavy and sink in the middle as debris accumulates.
- Place the netting on one side of the pond and secure it with ground stakes at one-foot intervals.
- Pull the netting over to the other side of the pond. Pull it tight enough to provide a good amount of tension. Doing so will help the net catch as much falling debris as possible.
- Stake the rest of the netting around the pond and trim any excess material.
- Remove leaves and debris from the net as they accumulate.
Moderate to Extreme Cold
(Often ranging from below 0 to 50°F)
At these temperatures, you’re going to have to deal with freezing water. In addition to the preparation steps outlined in the Warm to Moderate section, you need to decide whether to keep the pond in operation or shut it down for the winter.
Keeping your pond active
This option definitely requires more upkeep and not knowing what is going on under the ice can be especially nerve-wracking if you have valuable aquatic life in your pond.
As long as you have a well-organized plan, and take the proper measures to secure your pond’s health through the winter – it will be ready to flourish come springtime.
Prevent your pond from freezing over 100%
- Keep your waterfall feature active. Flowing water doesn’t freeze as easily as still water. Regardless, watch for freezing at the edges of the water feature, which can trigger flooding and water loss.
- Install/turn on an air pump. This is somewhat related to the principle behind the waterfall tip. An air pump keeps the pond water in motion, and it has the additional benefit of ensuring efficient aeration.
- Use a pond de-icer. If you live in an area that experiences bitterly cold winters and you’re afraid a waterfall and air pump won’t be enough to keep the water from freezing, consider a de-icer. If you are overwintering fish in your pond, it’s critical that a hole remains at the surface of the water to allow oxygen and sunlight in and to allow gases to escape from under the water.
- Use a pool heater. Many koi keepers swear by the use of a pool heater as a great way to ensure a healthy water temperature for your fish. Make sure that there is no copper in the heater, as it is toxic to koi.
Closing your pond for the winter
Many pond owners choose to circumvent dealing with the elements by simply closing up shop for the winter. If you own valuable fish and live in an area where winter temperatures are frequently very cold, relocating the fish is safer than attempting to overwinter them.
Follow these steps to ensure a safe and easy transition.
- Move pond fish to warmer waters. Safely transfer your valuable fish to their new home. It’s better to be safe than sorry. The main step you need to take to ensure a safe transition is letting your fish adapt slowly to large changes in water temperature.
- Move potted annuals indoors before the first frost. Place the pots in shallow water to keep the roots wet, and make sure the plants receive plenty of warmth and good light.
- Move valuable pond equipment inside. Move expensive equipment to where it won’t obtain frost damage.
- Drain filtration and pump lines. Water expands as it freezes, and this expansion can damage pond equipment. Around mid-October, drain all water from your pond and all filtration and pump lines to avoid this potential damage. Clean the pump and store it in a bucket of water where it won’t freeze. Keeping it wet will help prevent seals and O-rings from drying out and cracking.
- Install an air pump or de-icer. This step is optional, but we recommend installing one or both pieces of equipment to allow methane gases to escape the pond under freezing conditions.
Caring for Koi / Fish in Winter
Your finned friends need special attention as the seasons change. Regardless of whether you decide to overwinter them in the pond or relocate them, keep the following tips in mind.
- Put out predator decoys. Large birds, particularly herons, will look for easy prey before or during migration to warmer climates. As the water cools and your fish slow down, they become sluggish and turn into tasty-looking snacks for passing herons. A floating alligator or a heron “lookalike” will help deter hungry predators from making a meal of your fish.
- When the water temperature drops to around 55 degrees Fahrenheit, replace summer food with wheat germ. This will allow the fish to build up fat reserves that will sustain them through hibernation while overwintering in a pond. The fish will stop eating on their own as the water temperature continues to drop and they enter hibernation.
- If overwintering fish, do not feed them at all during winter. When water temperatures reach about 50 degrees Fahrenheit, stop feeding your fish. Koi and goldfish don’t have stomachs, and their metabolism is controlled by water temperature. When their metabolism is nearly stopped (i.e., during hibernation), food can rot in their guts and kill them. You can resume feeding in the spring when water temperature begins to rise.
- Move fish indoors before the water temperature reaches 50 degrees Fahrenheit.. This is usually around the first week of November.