Winter Pond Checklist

'Tis the season to be jolly and to prepare your pond for the cold weather.  We've put together a helpful checklist for a successful winter pond. 

Test the Water

A good place to start is to perform a water test, including oxygen level, which will help to determine what current conditions exist and to help examine the factors that contribute to them. You will also be able to create a plan of attack to combat the poor conditions in your pond and figure out the next steps that are needed. These can range from partial water changes, clearing debris, cleaning filters, using additives, or aeration, which all happen to be essential to the winterization of your pond.

Perform a Water Change

Water temperature is an important aspect to gauge when it is best to make changes that will help the overall health of the pond. Having a thermometer will help you determine at what point during fall to start different preparations. Generally, doing partial water changes is always a good idea during fall to help rid your pond of murky water. A good rule to follow is executing a 50% partial water change before the water temperature goes below 60°F. Remember to use a water clarifier or barley pond clarifier to keep your water clean and clear and a chlorine remover if your tap water contains chlorine or chloramines.

Clean your pond

Cleaning your pond is one of the most crucial steps in winterizing your water garden and should be done before the water temperature falls below 50°F. This is suggested since the fish will still be active and less likely to suffer injuries during cleaning. Ridding your pond of leaves and plant debris will help to avoid the breakdown of any remnants over the winter, which can cause a spike in harmful ammonia levels. Clear debris by scooping up fall leaves from the surface with a Skimmer Fish Net. During the partial water change, prune your marginal pond plants and remove floating plants to a safe place before they decay. Deep-water plants, like lotus and lilies, can be placed in the deepest part of the pond. Floating plants should be removed from the water and stored in warm, frost-free conditions, like inside the home.  You can use a pond vacuum and hose to remove the remaining debris and sludge from the bottom of the pond. To help avoid any more debris from entering your pond, we recommend covering your pond with netting and keeping the area around the pond raked. If necessary, use an additive like pond cleaner tablets to help accelerate the decomposition of leaves, scum, sediment, and other pollutants to keep a healthy balanced ecosystem. This will also help to make sure your pond is healthy when you reopen your pond in spring.

Closing Down the Pond

Determine when and if pond equipment like pumps, filters, and UV clarifiers should be shut down. If your winter temperatures are moderate than you can keep the pump running all season long to keep the surface from freezing. It’s also good to reduce the circulation of the pond water by either turning off the pump for the winter or preferably by placing the pump or the intake to the pump closer to the water outlet (waterfall or fountain) so it picks up water from mid-level of the pond. If you are keeping your equipment on, turn down the water flow. Keeping the water flowing through your biological filter allows the beneficial bacteria to live, which will make for good water quality early in the spring. 

If the temperatures are more extreme, we recommend shutting your pond down to prevent hyper-cooling, which is when colder surface water mixes with warmer water that is on the bottom of your pond, where fish hide and hibernate, changing the overall temperature. Also, you run the risk of diverting water out of the pond and emptying it when the flowing water begins to form ice, especially on features like waterfalls.

At a water temperature of 40°F or below, turn off and remove pond equipment.

Clean and Store Equipment

If you are choosing to close down the pond, we recommend cleaning the equipment and inspecting it to see if any components need to be fixed or replaced. Storing the equipment indoors safe from the elements will increase functionality and longevity. Make sure to check for water left in any device to avoid icing up and/or causing the body/housing to break if storing outdoors. For submersible pumps kept inside, it helps to place the pump in a bucket of water to keep the moving parts and seals wet. Cleaning your filters is important because a dirty filtration system is inefficient. It works harder, accomplishes less, and may clog and not work at all. Use this opportunity to clean everything, replace media if needed, and make sure it is in perfect working condition. Make sure they are drained, cleaned, and the features are working in top condition. Fix or replace any non-functioning pieces. 

Winter Pond Equipment

A heater or deicer is a good investment. Gases produced by decomposing organic material, are trapped under ice covering the pond’s surface and can be dangerous to fish. Deicer’s keep an area of the pond ice-free during the winter, allowing an exchange of the harmful gases to escape through the opening. In smaller ponds, a deicer is particularly helpful in avoiding ponds from freezing solid. Deicers alleviate stress for fish during the winter, making it easier for them to withstand diseases that are more predominant in the spring.

Fish Habits During the Winter

It’s usually best to leave fish in the pond during the winter, providing the depth of the pond is 18" or deeper and there is little to no water circulation. As cold weather approaches, monitor pond water temperatures daily. To successfully keep your fish or koi alive, you will need to change their feeding patterns when it gets to 60°F or below. Read our Fish Guide to keeping your fish healthy during cold months.

Here’s a condensed checklist:

  • Test your water and perform a water change
  • Clean your pond
  • Disconnect the pump, filter and UV clarifier before water freezes
  • Clean and inspect equipment
  • Store filters and UV clarifier indoors for protection
  • If storing submersible pumps, place in a bucket of water
  • Purchase or have the pond deicer ready for installation. It will melt a small opening in the surface, allowing toxic gases to escape
  • If you keep your filter running through the winter, reduce the flow
  • Monitor temperature and adjust feeding fish

Now make that list and check it twice to have your winter pond prepared!

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