Blanket Weed

Blanket weed is the most common complaint that I get from pond keepers. It is caused by a combination of conspiring conditions; nutrients, sunlight and hard water. Without food (nutrients) it cannot grow, without sunlight it withers and in soft water it struggles. In Dorset and Hampshire we have hard water, in most ponds there are nutrients from various sources and during the summer we get at least some sun.


Regular topping up of tap water increases the hardness of the water plus it can also add nutrients (depending on the quality of the tap water). Topping up with rain water can help also try to reduce the need to top up by reducing the amount of splashing from fountains and waterfalls.

Nutrients can be reduced by simply reducing stocking and/or the amount you feed. There is a lot of natural food in a pond, often fish don’t need extra food provided by a human. Feeding of fish is normally only for our benefit, the fish get used to associating people with food so instead of hiding when a figure appears near the pond they think lunch is coming.


Extra planting can help to reduce blanket weed growth by not only providing shade but by helping to ‘use’ up nutrients.

I tend to employ all the above methods and often use a treatment. Cloverleafs Blanket Answers is very effective or if you wish to use a more natural product try barley straw. Follow the link below to our web site for product information or if you so wish to buy this or similar products.