Getting your pond ready for winter

We get it, its going cold outside and perhaps the last thing you want to do if get your wellies on and prepare your pond for winter, but if you can brave the plummeting temperatures there is real value in a little winter preparation, something we see at Swell UK year in, year out.

Seasonal changes in your pond

As Summer draws to a close and the weather starts to bite a little more, there are plenty of changes that will occur in and around your pond that may have long term effects on your water chemistry and quality if left unchecked.

Some are easy to deal with! For instance, as Winter begins, you pond will likely receive considerably less direct sunlight, which means that free floating green algae and blanket weed will have less light energy to photosynthesise with, meaning your filtration system may have a chance of ridding your pond of that nasty summer bloom, especially with a little help from green water and blanket weed treatments.

But other effects can be very negative, and perhaps one of the biggest ones is the potential increase of decaying plant matter in your pond.

Unless your garden and that of your neighbours is planted exclusively with evergreen plants and trees, the natural cycle of your garden plants means they will soon be shedding their golden brown leaves, of which your pond is in danger of consuming.

While decaying leaves on your flower beds is less of an issue (becoming fertiliser for next spring), in your pond, it can be devastating. As this plant matter sinks to the bottom, it is broken down slowly over the winter by bacteria, increasing the levels of ammonia and nitrates in your pond, becoming fertiliser for algae the following spring.

The amount of sludge at the bottom of your pond (already building up through the active summer) will be reaching new heights by the end of winter too, if you haven’t already dealt with it. Clogging your filter and pump, and adding to a developing poor water clarity issue.

What can be done about it?

Leaves are easy. Deploying a suitably sized pond net over your garden pond will stop the majority of leaves from entering your pond eco system. Sure, it won’t look it’s best over the large portion of the winter, but it means your pond will be in better shape come the summer months when you are most likely to be able to get our and enjoy it.

For sludge, we recommend a Pond Vac or sludge remover. These Pond Vacs are specially adapted vacuum cleaners for removing dirt and debris from your pond water, and are best used at the beginning and the end of summer to remove most of the gross matter than will cause you problems later on.

Sludge eaters are the bio alternative to clearing this, in which bacteria is added to your pond to eat away at sunken detritus, but a combination of vacuum and sludge remover is the most effective for ensuring a clean pond.

Don’t forget to give your pump a clean too! Ensuring the impellor is not damaged or clogged is essential for having a working pump come the summer time when you need it the most. UV lights should be changed too after running out of output over the summer months, and filter sponges could do with a clean or replacing.

Your pond fish in winter

You need to think about your fish through the winter months too. Most fish will go through a period of relative inactivity during the cold times anyway, but they still need oxygenated water. A pond heater can be a great way to ensure this in the event of the water freezing over.

When this happens, your pond water will slowly lose oxygenation as it has no contact with the air due to the ice sheet. A pond heater creates an area of unfrozen water so your fish have a ‘blow hole’ to ensure oxygen is available.

Winter fish foods are also a good idea. Wheatgerm based fish foods are a great idea, providing slow release energy and less waste over the winter months.

Georgina Posted by on

Georgina is a member of the Swell UK marketing team and has been keeping tropical fish for a number of years now. Her favourite fish being the stunning, male Siamese Fighting Fish. She is also looking to expand her existing collection to include keeping saltwater fish as well. Her other pets include Bengal cat, Walter, and Labrador and Rottweiler cross, Presley.


  • Avatar Gillian Hoskins Posted 11/12/2015 at 12:07 pm | Permalink | Reply

    hi my pond is 8ft x 6ft by 3ft deep, i have not gone through the winter yet, only put the fish in last march, its of the ground with flowing pump a netted cover and a wood roof over it, Do you think mine will still freeze over,

    • Georgina Georgina Posted 14/12/2015 at 3:15 pm | Permalink

      Hi Gillian
      Water going back into the pond should cause disturbance on the surface to prevent ice from forming in that area. However should the winter be very bad, it may be worth investing in a pond heater, we have two on our site –
      Kind regards

Add your comment

* Required fields