How to clean a pond

Regular maintenance is very important for a successful pond. Cleaning a pond isn't difficult but you need to take weekly action between April and October. Look carefully to identify problems before they become critical. With a little maintenance, a correctly positioned and planted pond can be a pleasure, not a chore. So, here's our guide on how to clean a pond.

How to clean a pond

How to clean a pond

Protecting your fish

  • If herons are a problem, leave a pond net in place over the winter.
  • Don't break winter ice by hitting with a hammer – the shock waves can kill your fish. Instead, place a hot saucepan near the edge of the pool and gradually melt a section of ice.

Cleaning and maintaining a garden pond regularly is necessary to keep the pond looking good and keeping any fish healthy. So here's our guide on how to clean you pond.

Safety first
Children love water, but it goes without saying that a pond can be a hazard to little ones. Take the time to consider if you need to take any safety precautions with your pond, if children are going to be anywhere near it. If you're worried, why not consider installing a water feature instead.

Keep your pond clean
Dead and dying plant material rots, polluting the pond water, so use a fine mesh net to clean out the pond each week from spring to autumn. If trees are near your pond, suspend a net over the top of the pond to catch any falling leaves, particularly in October.

Maintain about 60% surface cover by planting water lilies to keep water temperature low and restrict algae growth. When temperatures warm up, the water may take on a greenish hue, but your pond should clear when the lilies start to grow.

In autumn, when plants around the edge of the pond might die, keep foliage trimmed before it drops into the water. Clean out the pond filter and pumps (if fitted) in autumn and at other times in accordance with the manufacturer's instructions.

Fishy friends
Don't feed any fish unless the water temperature exceeds 10°C (50°F). You'll notice when the fish are active and searching for food - over winter they live on fat reserves and plant roots. Feed fish sparingly at first so that any uneaten food does not rot and pollute the pond water.

If you see fish coming to the pond's surface to breathe at any time of the year, it could be that the water's oxygen is low. Turn on the pond's fountain, if you have one, to oxygenate the water. If not, sprinkle the surface with fresh water from a hosepipe.

Keeping the pond in balance
Keep an eye on the pond in warm weather and replace evaporation losses regularly, but gradually, to prevent a sudden influx of fresh water.

A gaseous exchange between the pond and atmosphere is necessary to keep up oxygen levels and allow carbon dioxide and other poisonous gases to escape, so if the surface of your pond freezes in winter it is essential to keep an area ice-free or the poisonous gases will build up and kill your fish and plants. If you suspect the pond will freeze, float a ball in the water to create a gap in the ice.

Turn off your fountain in cold weather. The mixing of warmer water at the bottom of the pond with cold water at the surface will lower the overall pond temperature and could harm your fish. Only use fountains in cold weather if they can be lifted to the surface level so that mixing will not occur.

More pond guides

  • How to build a pond
  • Video: How to build a garden pond
  • How to encourage wildlife to your garden