Winter Pond Care

There isn’t a great deal for the pond keeper to do in the winter months after the autumn cleanup its time to sit and wait out the winter. There are a few duties still required to ensure that the pond and its pondlfe get the best chance of making it to Spring.

Firstly, you should have a good quality strong net over your pond for winter. I use a Clearview nylon net for Spring and Summer, this is so I can see the fish and let the plants grow nice. However in Winter, I want everything secure and seeing the pond isn’t the priority, so I use a heavy duty wire mesh. Again, I lost fish last year, the disappeared without a trace and when I spoke to a fellow Pond keeper they said it could be Mink.

I thought Nah! but it did get me thinking and I do live close to a river so who knows, anyway, I want the pond secure for Winter and that means trimming back any plants which will benefit from this and thrive and grow next Spring.

Another area – which is probably the most important, is what to do when the pond freezes over.

First off, the Pond will never freeze right to the bottom so most hardy Koi and Goldfish will be ok, even during the big UK freeze of 2010 with temperatures dropping to -17c it didn’t freeze right down to the bottom.

There are many opinions about whether it is advisable to leave your pond pump running during the winter months.

Advocates against say that you should turn off the pump in winter. There is an obvious saving to be made in electricity and this can increase the life of the pump by giving it a winter break. Coupled with this is the reduction in algae and blanket weed growth in winter due to colder temperatures and less sunlight so the filter is not required to cleanse the water as much.

In general though, I would say it is advisable to keep the pump running in winter albeit in a reduced capacity than in the warmer months. Some pumps come with the ability to control multiple water features. Such as a water fall feature and separate statue water features. It is best to run only some of the water features rather than all. Not only will keeping at least one of the water features going introduce oxygen into the pond, it will keep the water on the surface circulating and this has the added benefit of helping prevent the pond icing over as quickly, when the temperature drops.

Another benefit of running the pump as long as possible is the reduction of nitrogen in the pond. Nitrogen buildup happens naturally due to the rotting matter which decays in the bottom of the pond. Nitrogen buildup can be bad news for health of any resident fish population. A pump helps remove this nitrogen and recycles the water replenishing it with oxygen.

If your pump has a UV filter it would be good practice to take out the bulb and save it for spring. As mentioned above algae and blanket weed does not present as much of a problem in winter and running the UV filter through winter will only decrease the life of the bulb.

That said, there are occasions when it is advisable to switch your pump off completely, namely when the pond starts to freeze over. If the pump or the pipes start to freeze this will inevitably increase the pressure on the pump and may result in a burst pipe.

It is advisable to ensure that should the pond freeze over and the pump is left off, a hole is kept in the ice to allow release of nitrogen in the pond to escape. Their are two methods you can use, I employ both :

A tennis ball allowed to float freely disrupts ice buildup (to a point)

And/or

A boiled kettle poured continuously onto one spot is the best way to gently melt the ice until the temperature warms up. The pond will never freeze right to the bottom and this amazing quality of water is what allows pond fish to escape being made into a freeze pop. Never break ice forcefully as it can create soundwaves which can stun or kill your fish.

The pump should be removed from the pond and cleaned out at the start of spring to remove any leaves or matter which may have got trapped. Good husbandry of your pump will keep it prolong its life and help keep your pond and fish healthy.

Lastly, the decision to switch off the pump or leave it running during winter is down to the pond owners opinion and experiences. I would say from my own experience that the overriding benefit to keeping the pump running is the oxygen introduced to the pond which can only benefit the health of the fish.

And bar keeping a hole in the ice there isn’t much else for you to except sit back and plan your big Spring pond clean out and what new plants and fish you may want to add.

2012 Update – With such a mild winter this year in Northern UK, my pond has only threatened to ice over once in December so far. With temperatures much milder (but way above 5c cutoff point) than last year, I have started feeding my fish again infrequently in January, with very small portions as they have became active. But if the temperatures drop again I will stop, its the keepers call but base your decision to feed or not on the 5c rule and not the season.

For spring advice, read my spring pond care article.
For summer/autumn advice, read my summer/autumn pond care article.