Pond turtles and duckweed.

[KellyBean]

We have just acquired a ranch with 2 fairly large ponds that are covered with duckweed. There also are quite a few large (6-10") turtles living in it. I think there may be some fish in it also. Is there something we could use to kill the duckweed without harming the turtles or fish? We also see herons sitting on the log. We are in Zone 5 or 6 in Oregon. Thanks in advance.

 

[addy1]

Welcome to our group!

This is from the web:

Biological Duckweed Control Add natural predators of duckweed, such as Koi, grass carp, goldfish and domesticated waterfowl. Alone these biological controls cannot remove the problem, but if introduced to the pond before duckweed begins to grow, they can assist with duckweed control. Get rid of duckweed before it takes over the pond by increasing aeration at the bottom, manually removing plants from the surface and reducing nutrients that create bottom sediment. Try a combination of these methods before resorting to chemical duckweed control.

Read more at Gardening Know How: Controlling Duckweed – How To Kill Duckweed https://www.gardeningknowhow.com/plant-problems/weeds/duckweed-control.htm

 

[GBBUDD]

the extreme would be something in this idea

 

[Stephen Noble]

Not sure how big your ponds are but vigorous aeration is helpful. If the ponds are not too large, you can use a leaf blower and a swimming pool net. Have someone hold the net and blow & corral the stuff. Toss the duckweed into a compost pile. Start the aeration after you skim off most of the duckweed. Goldfish also devour it. Doing the above is environmentally sound. By the way, welcome to the forum!
Stephen

 

[Becky]

Welcome to the forum

 

[Wayfarin]

We have just acquired a ranch with 2 fairly large ponds that are covered with duckweed. There also are quite a few large (6-10") turtles living in it. I think there may be some fish in it also. Is there something we could use to kill the duckweed without harming the turtles or fish? We also see herons sitting on the log. We are in Zone 5 or 6 in Oregon. Thanks in advance.

There are a few ways to control duckweed without harming fish and turtles, but the most effective solution would be a combination of powerful aeration and skimming the surface with a net. Many pond creatures, such as goldfish, domestic ducks, and even turtles themselves consume duckweed, but they are more efficient at preventing overpopulations before they occur than wiping them out.
I don't know if this helps but duckweed is not harmful at all to turtles and fish unless there are literally no open areas.
Duckweed actually helps by controlling algae, but it also starves submerged plants.