Winterizing your garden pond is a must if you live in a cold climate like I do! In this post, I will show you exactly how to winterize pond fish, plants, pumps and waterfalls. Plus, I will give you the steps that I take to prepare my pond for winter.
I have two small garden ponds on my property, both of them have hardy plants and goldfish living in them. I overwinter both the plants and the fish in the ponds, which is much easier than overwintering them in the house.
But don’t worry, it sounds much harder than it is (and you don’t have to remove hardy fish and plants!). Below are steps to wintering a backyard garden pond.
Should I Drain My Pond In Winter?
The short answer is no. There’s no reason to drain the water, and more than likely it will fill up with rain and snow during the winter anyway. So, as long as you take the proper steps below for winterizing your pond, there’s no reason to drain the water in the fall.
Getting ready to winterize my backyard pond
How To Winterize A Pond
In this section, I will give you the steps I take for wintering my pond. Then, in the sections below, I will talk in more detail about how to winterize pond plants, pumps and fish, and also give you tips for winter pond care too.
Step 1: Clean the pond – Decomposing organic material, like fallen leaves, releases toxic gases that can build up in the water and kill overwintering pond fish. So it’s important to remove as much organic material from the pond as you can before winterizing it.
To make garden pond maintenance easier in the fall, cover it with pond netting to help prevent leaves and other debris from falling in. Once the leaves are done falling, use a pond skimmer net to remove any that got through the netting. Learn how to clean your pond step-by-step.
Removing leaves before winterizing fish pond
Step 2: Prune pond plants – Pull the pond plants out of the water, and prune them back to remove all the foliage down to the base of the plant. Just like with leaves, decomposing pond plant material can cause toxic gases to build up in the water, which is very dangerous for the fish.
Step 3: Add cold water bacteria – Cold water beneficial bacteria helps to break down the fish waste and debris to keep the pond water cleaner and clearer during the winter months. This helps to reduce the chances of toxic gas building up in the water.
Step 4: Turn off pump – The next step I take for winterize my garden pond is to turn off the pump, and clean the pond filter. I also remove all the parts that are sticking out above the water surface, including the waterfall tubing and the fountain attachments. That way they won’t get damaged when the water freezes in the winter.
Step 5: Put the plants and pump back in – Once I get most of the debris out of the pond and everything cleaned, I put the plants and the pump on the bottom in the deepest part of the pond.
Step 6: Add fish pond heater – The last pond winterizing step that I take is to add my floating pond de-icer. If you’re overwintering fish in your pond, then it’s very important to keep a hole open in the ice during the winter. Oh, and if this is your first year having a pond, then you could get a pond winterizing kit like this one to help make it even easier!
How To Winterize Pond Pumps
Like I mentioned above, I leave the pump in the bottom of my pond through the winter. Since the water won’t be freezing to the bottom of my pond, it won’t harm the pump. If you prefer, you can remove the pump from your pond and overwinter it in a basement, garage or shed.
I definitely recommend removing the pump if you don’t plan to prevent the water from freezing over. Otherwise, if the water freezes completely, it could cause severe damage, or even destroy the pump.
When To Turn Pond Pump Off For Winter
If you live somewhere with very cold winters like I do, then it’s best to turn your pond pump off before the water starts to freeze. If you plan to leave the pump in the water all winter, then you can leave it running longer.
Just be sure to keep a close eye on it once ice starts forming on top of the pond. Otherwise the water can start to run over the top of the ice, and out of the pond. An you definitely don’t want to accidentally drain your pond!
Running Pond Pump In Winter
If you live in a warm or mild climate, then you can leave your pump running all winter long, or use a pond bubbler for winter. Running water will prevent a pond from freezing over in mild climates, and provide winter pond aeration. Again, keep an eye on the water level if there are any cold spells to be sure the water isn’t being diverted out of the pond because of ice build up.
How To Keep Pond Plants Alive Over Winter
Hardy plants, like water lilies, will survive in a frozen fish pond through the winter. So you don’t need to worry about removing them. Just cut back the foliage and then put them into the deepest part of the pond. Tropical plants however won’t survive the winter in the pond, so they should be removed and discarded, or overwintered indoors.
How To Keep Pond Fish Alive In Winter
If you’re wondering what to do with pond fish in winter… well, that depends on the type of fish you have. The fish in my pond are goldfish, and they can survive the winter in the pond as long as the water doesn’t freeze over completely.
Koi are also pond fish that can survive winter, as long as the water doesn’t freeze completely. Tropical fish however should be overwintered indoors.
Keeping goldfish in pond over winter
Keeping Fish In A Pond Over Winter
If you plan to overwinter fish in your backyard fish pond, then you must keep the water from freezing over. Keeping an open area will allow the toxic gases to escape, and oxygen to enter the water to keep the fish alive through the winter.
Keeping a hole in the ice will also prevent the pond from freezing to the bottom. If the water freezes to the bottom, it could kill both the plants and the fish (and probably the pump too).
How To Keep Pond From Freezing Over
Moving water will keep the pond from freezing over during the winter in mild climates, so you can just leave your pump running. But if you’re in a colder climate like I am here in Minnesota, you will need some kind of a pond heater for winter (also called fish pond de-icers) to keep a hole open in the ice.
Sometimes during extreme cold spells, my goldfish ponds will freeze over even with my pond water heater. That’s ok since it usually only lasts a few days and the hole will open up again.
Floating pond heater to keep pond from freezing
Winterizing A Pond Without Fish
If you don’t have fish in your pond, then you don’t have to worry about keeping the water from freezing over. Hardy plants should survive just fine. But, if you don’t plan to put a heater in there, you should remove the pond pump and filter box. Otherwise if the pond freezes to the bottom, it could destroy your pump.
How To Winterize A Pond With A Waterfall
If you live somewhere warm you can leave the waterfall running all winter. However, if water freezes on the waterfall it can divert the flow of the water, and quickly drain the pond. So, if you have freezing temps at all, then I recommend turning off the waterfall during the winter.
Ice buildup on pond waterfall
Winter Pond Care Tips
- If your pond has already frozen over, do NOT try to open a hole in the ice by pounding on it. Just lay the pond de-icer on top of the ice, and eventually it will melt through and open a hole. I learned the hard way to never pound on the ice, because it can kill the fish. (I killed three of my fish one winter by pounding on the ice, I was so upset!)
- Don’t feed your fish during the winter. Fish don’t digest food very well when it’s cold, and feeding them could end up killing them. Feeding pond fish in winter could also cause harmful gases to build up in the water as the food decomposes. Don’t worry, the fish hibernate during the winter and don’t need food anyway.
- Snow adds a layer of insulation over the pond heater, and helps to keep the hole open. It also helps the water stay warmer than it would if there was no snow. So don’t worry about removing the snow on top of your pond, just be sure the hole isn’t buried for too long.
Floating heater keeps pond open in the winter
In this post, I showed you how I prepare my pond for winter, and gave you details about how to winterize pond plants, fish, pumps and waterfalls. Winterizing a pond isn’t difficult, but it’s important in order to avoid damage to your equipment, and keep your fish and plants alive through the winter.
Up next, learn how to keep pond water clear naturally.
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More Fall Gardening Tips
- How To Protect Plants From Frost Damage
- 5 Tips to Simplify Fall Garden Cleanup
- 5 Essential Fall Garden Tasks You Should Never Skip
- How To Winterize Your Garden In The Fall
- How To Prepare Your Vegetable Garden For Winter
Share your pond winterizing tips, or add some of the steps you take to winterize pond fish, pumps, plants and waterfalls in the comments section below.
Jim says
Hi Amy, I’m curious about the depth that your outdoor ponds freeze. We have a 700 gallon, 42” deep raised pond with a 4 step down waterfall feature. Last year we brought our fish in and tested the pond to see how deep the water would freeze. Here in Toronto,ON, we found that it froze 18” on top. Would a pond heater keep it open or will we need a bubbler as well. We want to leave the Koi and Goldfish in this winter.
Amy Andrychowicz says
I have never checked to see how deep the ice freezes in my ponds. But I’m pretty sure it would go all the way to the bottom, or close to it (they are about 2′ deep) during the coldest winter months if I didn’t put the heater in there. The pond heater works to keep the water open in mine all winter, expect once it gets down to about -15F or so. We usually only have a few weeks of temps that cold, and the ponds freeze over despite the heater. But, since it’s for such a short time, my fish can still survive so I don’t worry about it. I’ve never tried using a bubbler, so I can’t speak from experience there. I should specify that I have goldfish, and they are extremely cold hardy. I’m not sure if koi would survive in the pond through our extreme cold winter here in MN. They are not as hardy as goldfish.
NICOLE says
We dont remove the pump in the winter, we live zone 7, very cold winters, but we live the fountain and the skimmer on , all year round and add the pond heater right in the middle of the pond, in the winter. We feed the fish 1-2 times a week in the winter, since they dont really hibernate, we also add kosher salt after we clean the filter. Our fish are very colorful and happy.
Amy Andrychowicz says
Awesome, thanks for sharing your tips for how you overwinter your pond and your fish.
esther zimmerman says
I am a new shubunkin goldfish container pond owner. I live in New York and I was very happy to read your article about winterizing a pond, especially since you live in MN and it is much colder there than NY. In your pictures, your pond looks very small. I am curious to know how deep it is as your fish were able to survive the cold MN winters. I have a 100 gallon above-ground stock tank container pond that has a water depth of 18 inches although the of container is 2 feet deep. I want to make sure that my fish will survive in my pond if I use a deicer.
Amy Andrychowicz says
I have two small ponds, both are about 2′ deep (though I’ve never actually measured). However, mine are sunk into the ground, so the bottom of the ponds sit below the frost line. That is why I am able to leave the fish in there all winter with a stock tank heater. The ground and snow cover insulates them, and the heater keeps a hole in the top of the water open, so they won’t freeze to the bottom. If they were above-ground, the heaters would not keep them from freezing to the bottom here in MN. But it does get bitter cold here in the winter, it’s not uncommon for it to get down to -20F (with a -30F windchill) for a few weeks in January/Feb on a bad year. When it gets that cold, even the heaters can’t keep the water from freezing over the top (though they have never frozen to the bottom).
Marlys Blomquist says
Great tips, thank you! My daughter wants to do her part in helping save Illinois aquatic turtles and build a pond that is safe all year round. Do you know if there are any different steps we should take with turtles instead of, or in addition to, fish?
Amy Andrychowicz says
Oh how cute! Sorry, but I don’t have any experience raising turtles. Good luck with it though!
Jane Nelson says
Thanks for all your helpful tips.
Amy Andrychowicz says
You’re welcome!
Sally says
Thank you Amy this is a great article. I live in Denver Colorado and have two fantail goldfish. My pond is 18in deep. Can I keep them in the pond over winter with a d icer?
Amy Andrychowicz says
Yes, as long as the water doesn’t freeze to the bottom, and there’s an air hole (which the deicer will create), your goldfish should survive the winter in your pond just fine.
Cheryl says
I’m just putting my pond in and am starting with goldfish. Do you feed the during the winter
Amy Andrychowicz says
No. The goldfish will hibernate over the winter and don’t need to be fed. However, if you’re just putting your pond in now, then I would wait until spring to add the goldfish. No reason to try overwintering fish in a brand new pond.
MARY says
I also have two rubbermade ponds on the south side of my house that I lay a pane of glass partially over them and they stay partly thawed all winter unless it’s way below 0 deg.
Amy Andrychowicz says
Cool. Thanks for sharing your method of keeping your ponds from freezing over!
mary says
I have a small 50 gallon sheep tank that I sunk into the ground this summer. I’ve always had to take my fish in in the winter (3 shuebunkin) but am considering leaving them out this winter. It’s not very deep, maybe a foot, but with it being in the ground I’m hoping will help keep the water from freezing all the way through?
Amy Andrychowicz says
Depending on where you live, you may need to add a stock tank heater in order to keep the fish alive. If you live in a climate that’s cold enough where the top of the water will freeze over for more than a couple of weeks at a time, then you’ll definitely need to get a stock tank heater to keep the water open so that air can circulate and the fish won’t die. Here in MN, a one foot deep tank like that would definitely freeze to the bottom without a heater, even if it’s sunk into the ground.
Marisa says
These are great tips for winterizing my pond.. definitely sharing this!
Amy Andrychowicz says
Great! Thanks so much. 🙂
liz says
I do all of the same steps as you, except Icover my pond with a net and place an air stone bubbler in my pond instead of the heater. Twice I lost all of my koi due to the heaters, so switched over to the bubblers and all has been fine for the last 15 years. When I lived in Colorado, we could keep the falls on all year which was so nice – but here in CT, it all gets closed up.
Amy Andrychowicz says
Interesting… how did your koi die from the pond heater?