View Full Version : Eradicating duckweed

26th July 2008, 23:10
I have a problem with duckweed (Lemna minor) in one garden pond, and I am worried that it will soon become a problem in my new pond. Is there any way to get rid of it entirely from a pond - I net it off, but loads of it gets stuck around the emergent plants? I have looked on the web and the two options that are possible for me are introducing fish such as koi, or using herbicides. Neither of these appeal to me as both pools are amphibian ponds (Rana temporaria, Lisotriton vulgaris), and both fish and herbicides would have a massive impact amphib populations.

The only thing i could think of was to introduce the fish in late summer, sacrifice a year's breeding season and remove the fish once the duckweed is gone. The only problem with this is that both ponds are quite shallow and the fish probably wouldn't be able to get to all the duckweed to eat it all.

I suspect that I will just have to keep on netting, but any tips would be very gratefully received!



27th July 2008, 07:48
The more turbulence or water circulation their is the harder it is for duckweed to grow. Air stones, water pumps, etc will slow it down. Introducing some aquatic shrimp might also knock it down a little.