Your pond in hot weather

Your pond in hot weather

Next week's weather should be hot again!

Watch out for water loss from your pond or container pond due to evaporation.

In normal summer months the effect of the sun can cause around 2 to 3 cm of water loss from your pond in a week.

At the moment this could be more. Both through evaporation and because the plants will use more too.

You need to check for water loss and top up your pond in hot weather:

  • Ideally use rainwater from a water butt to avoid adding nutrients or chlorine to the pond water.
  • If you have to use tap water then add Chlorine Guard to reduce the effect of the chlorine.
  • Add Chlorine Guard every time you add tap water to the pond,
  • This is an environmentally friendly product based on seaweed extracts that are safe for fish, pets and wildlife.
  • Excessive water loss will cause distress to fish in your pond.
  • Wildlife in the top shelf area will become exposed to predators as the water level falls.
  • Pond plants on the shelf will suffer or die if their roots cannot reach water.
  • Pond liners will be exposed to strong sunlight and become at risk of splitting.

Other hot weather issues:

  • Water features and filters may block up with excess algae/blanketweed growing faster in the heat.
  • Your pipework may spring a leak by being exposed to the sun and cracking if it is not made from uv stabilised material.
  • Moving water features may run out of water which will allow the pump to run dry and burn out.
  • Your pond liner may be punctured by animal and pet claws as they try to drink from the pond.


  • Treat the pond more frequently in hot weather with liquid Barley Bio Algae Control. A safe, organic method.
  • Make sure your Barleystraw minibale is still active and not going black quicker than usual in the heat. If it is then add a new one & prepare to remove the old one in a month.
  • Back up the minibale treatment in the short term with Barley Bio during the heat wave.
  • Clean the filter and pump more frequently. Use old pond water (not tap water) to keep all your beneficial bacteria.
  • If you find a hole/split in the liner - patch it with a piece of liner fixed with a waterproof adhesive.
  • Add more waterlilies to your pond so their leaves cover more of the surface area of the water and shade it from the sun's heat.
  • Cut back Iris plant foliage to 6" above usual water level.
  • Tall foliage loses a lot of water so reduce the height and reduce the load on the pond's limited water resources.
  • Leave a good 6" stem height though for dragonflies to climb up to leave the pond.

If you are going on holiday look at the weather forecast.

  • If no rain is due add shade over your pond from a gazebo to keep the water cooler and reduce evaporation.
  • You will not be there to see that it may not look attractive.
  • It will help to reduce the problems of these hot temperatures on your pond in your absence.