To kill duckweed, how deep must it be buried? We are going to use a digger, so can be quite deep.
I was unable to find any information about burying Duckweed.
Here is a link with more information on Duckweed.
I would also talk with your local County Extension Office.
Can I use copper sulfate to kill duckweed in pond water that I irrigate the garden with?
We do not recommend the use of copper sulfate to kill Duckweed.
Here is an article with more information.
How are goldfish able to kill off duckweed? Wouldn't the duckweed kill off the goldfish due to the lack of oxygen and nutrients in the pond? What is the biological makeup of duckweed? What's your background surrounding duckweed? Can duckweed populate a bigger body of freshwater such as a lake (ex: Gull Lake in Brainerd, Minnesota)? If so, at what level does it populate the water? What effects does it have on the ecosystem there and at what level?
Goldfish, Koi and grass Carp can help with pond Duckweed, but will not eliminate it completely.
Our expertise is more geared to garden ponds, a much smaller scale then lakes.
I would suggest contacting the MN DNR for specific information on your questions.
I have listed several links for you as the very matter of aquatic weeds is well studied in the great state of MN!
I have a very small garden pond. It has been covered in duckweed for several years. Manual removal never suffices. I dislike using chemical weed killers of any sort, but if you can suggest one that is not too generally harmful I would risk it. There is one lone goldfish too, the last survivor.
Try tying dry straw in a bundle, about the same size as a small bunch of flowers, and float it on top. Eventually it will start to sink and may help to solve the problem without murdering Goldy.
Are there any benefits to duckweed? I read it was an invasive plant, but how does it spread? Where is some good info on this plant? I want to know more. Thank you very much.
Yes, it can easily become invasive.
This article will help you.