Winterizing Your Koi Pond

Winter in Ohio can be tough on koi ponds, but with the right preparation, you can keep your fish healthy, protect your equipment, and make spring maintenance a breeze. Over the years, I’ve found that taking the time to winterize your pond properly pays off by ensuring everything stays in great shape through the cold months.
Some folks choose to keep their pond running during the winter, while others prefer to shut it down entirely. Either way, there are a few key steps to follow to make sure your koi and pond are ready to thrive when warmer weather returns.

Install Pond Netting to Catch Leaves Early

If you haven’t already, installing pond netting before the leaves start falling is a huge time-saver. A good pond net will catch debris before it sinks to the bottom, making cleanup simple. Once all the leaves have fallen, you can just roll up the net, toss the leaves, and store it until next year. Trust me—this one step can save hours of work down the road.

Remove Leaves and Debris

If you didn’t get a chance to use netting, don’t worry. A long-handled pool skimmer or hand net works well to scoop out leaves and debris from the bottom of the pond. I can’t stress this enough—leaving organic material in the pond to decompose over winter leads to poor water quality and a big mess in the spring.

Clean the Skimmer Basket

Check your skimmer basket every few days during the fall. Once most of the leaves have dropped, you won’t need to check it as often, but keeping it clear while debris is falling will help your pond run smoothly.

Trim Dead or Dying Foliage

Cutting back dead or dying foliage is an important part of winter prep. Plants like hardy marginals can stay in the pond after a trim, while tropical plants should be removed and added to your compost pile. The idea here is to reduce the amount of organic material that could decompose in the water.

Prepare Waterlilies for Winter

If you have hardy waterlilies, trim them back to about two inches above the crown and move them to the deepest part of your pond (at least two feet deep). Tropical waterlilies are a different story—you can try to overwinter them indoors under a grow light, but they’re often best composted if they’re not going to survive.

Add Cold Water Beneficial Bacteria

Cold water beneficial bacteria are a game-changer for winter pond care. It works at temperatures as low as 32°F, helping keep the water clean and clear by breaking down debris and reducing the need for a big cleanup in the spring. Adding this regularly during the colder months will improve water quality and clarity.

If You Keep Your Pond Running

If you decide to keep your pond and waterfalls running, you’ll enjoy beautiful ice formations throughout the frosty season. That said, it does require a bit of upkeep:
Keep an eye on ice formations to ensure they don’t create dams that could lead to water loss over the edge of your stream.
Be prepared to top off the pond occasionally, as evaporation still happens during winter.
Make sure the surface of the pond doesn’t freeze completely. A small aerator or pump placed on the top shelf of your pond can keep a hole open for gas exchange. In extremely cold conditions, a floating pond heater might be necessary.

If You Shut Down the Pond

If you’d rather shut your pond down for the winter, here’s what I recommend:
Remove the pump and store it in a warm, dry place like your garage or basement. This helps extend its lifespan.
Drain the plumbing to prevent freezing and cracking in the pipes.
Clean and store the filter media after spraying them thoroughly with a garden hose.
Oxygenate the water by placing a 500-1000 GPH recirculating pump on the top shelf of your pond. This helps keep a hole open in the ice for gas exchange, which is critical for your fish.
If temperatures drop extremely low, consider adding a floating pond heater for additional protection.

Ensure Healthy Fish Before Winter

Your koi’s health going into winter makes all the difference. As water temperatures drop below 60°F, switch to a scientifically formulated winter blend koi food that’s easy for them to digest. Once the temperature dips below 50°F, stop feeding altogether. Their metabolism slows down at this point, and they won’t need food until spring.

A Little Effort Now Pays Off Later

Taking the time to prepare your pond for winter helps your fish survive their cold-weather slumber and makes spring maintenance so much easier. By following these steps, you can enjoy the beauty of your pond year-round and look forward to a fresh, vibrant start when the weather warms up.

At KAH Landscaping, we know how important proper winterization is. If you’d like professional help or tailored advice, reach out to us today—we’re here to make sure your pond and fish are ready for whatever winter throws at them!