Winter maintenance tips for your garden pond

If you have not already carried out your end of summer/autumn pond maintenance then it is advisable before the weather becomes too cold and ice covers the pond's surface.

Marginal plants would have died back and quite likely have fallen into the water. These will need to be cut and removed so that the decaying matter doesn't poison the water with too much carbon dioxide.

Also, remove fallen leaves as soon as possible - ice that forms on top of ponds with a high build-up of organic matter will retain a higher concentration of Co2.

In summer months, algae and pond plants photosynthesise and produce oxygen which is consumed by fish and other wildlife - even though pond plants and algae continue to photosynthesise during the winter, lower temperatures and reduced day length will mean a lower concentration of oxygen; any excessive build-up of Co2 can cause severe stress in fish. More on Co2 in fish ponds.

If you have a pond pump then it is time to do a little maintenance. First, drain your pump. Pumps are sealed so as to protect then from water getting into any electrical parts - don't ever try to access the electrics, if you have a problem, always seek expert advice.

Impellers - the part that drives the water through the pump - can become partially blocked or damaged and this is usually accessible for maintenance. Take all moveable parts off (including fountain attachments) and ensure that they are clear and clean. Rinse and scrub using a nylon bottle brush inside of cavities and tubes - whatever you do, don't use any chemicals that are likely to cause irritation or damage to your fish or plants. Replace damaged or worn parts.

Making sure that the pump is free of any water, store in a workshop shed. Some people like to run a small pump (this may not be your main oxygenating pump) or water heater during the winter. This is merely to stop the surface fully icing up.

Do not over-feed your fish. Fish will not be feeding a great deal during the winter and often there is natural food to help sustain them. Any residual food just rots and adds to the de-oxygenation of the water.

If you are planning any repairs to the fabric of your pond then take special care with cement based products. Small ponds are easily contaminated by silicates as they are leached into the water - this obviously means that mortar excesses should not be allowed to drop into the water.