Common pond problems

Do you have a problem with your pond but are not sure what is causing it and the best way to deal with it?

Too much duckweed

Origin: Often brought in from outside sources e.g. ducks. Also caused by excessive chemicals and nutrients.

Solution: Scrape off with a board or remove weekly with a sieve. Stock the pond with extra plants to oxygenate and shade out the weed.

Wildlife Implications: Great for attracting frogs and amphibians as it offers good camouflage from predators whilst in the pond.

Too much blanketweed

Origin: High nutrient levels and increased light levels in spring allow blanketweed to flourish before other plants are able to grow. Only problematic in small ponds. May also be brought in by other sources e.g. planting or other pond life.

Solution: Remove some of the weed using a rake. Drag the weed out on to the side of the pond, sort through and return as many creatures back to the water as soon as possible. Leave the weed on the edge of the pond for a further 48 hours to allow any remaining creatures to find their way back into the water. Remove the weed and compost it.

Wildlife Implications: Blanket weed is used by a range of pond amphibians and invertebrates as hiding places. It also offers a good food source.

Green water

Origin: Algal bloom. Common in new ponds filled with tap water and may recur in spring because of increased light levels. If suddenly occurring in a new pond it may indicate a pollution incident i.e. leeching from compost bin or run off from chemicals used in the garden.

Solution: If it is a new pond, you will need to leave the pond to stabilise. Adding barley straw or old willow stems can sometimes be beneficial.

Wildlife Implications: Do not use chemical controls to sort the problem as this may prevent important microscopic algae grazers from colonising the pond.

Brown water

Origin: Low oxygen and high nutrient levels causing an imbalance, especially if you have water fern (which produces nitrogen).

Solution: Add pollution-tolerant oxygenating plants, such as yellow and white water lilly.

Wildlife Implications: Low oxygen levels may limit the variety of wildlife in your pond.

Punctured liner

Origin: Sharp stones, roots, dog's feet, or a hand tool penetrating the liner.

Solution: Patches and kits are available from local garden centres to fix pond liners. As a last resort, turn punctured pond into a bog area and build a new pond next to it.

Wildlife Implications: Draining and refilling could cause massive disruption to wildlife.

Grass and leaves blowing into pond

Origin: Overhanging trees and shrubs.

Solution: Cultivate a fringe of tall grass or vegetation at pond edges to catch leaves and grass cuttings.

Wildlife Implications: If you use netting then your pond amphibians can easily get caught up in it. Ensure you leave at least a 2-inch gap between the ground and netting for animals to get in and out of the pond.

Frozen pond

Origin: Temperatures below freezing.

Solution: Float a ball on the pond overnight to prevent the pond from freezing. If it freezes, clear any snow off the ice to allow light to penetrate through. Don’t break the ice as the shock waves can kill the animals. Ultimately, good water quality and allowing plenty of submerged plants to grow is probably the best way to ensure your pondlife survives the winter.

Wildlife Implications: In frozen ponds, noxious gases can build up causing hibernating amphibians within the pond to die.

I don't have space for a pond. What can I do instead to help wildlife?

Posted in: Ponds on 30 April 2015

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