Duckweed Treatment

I had a pond owner call last week asking about how to successfully treat his duckweed. His pond has had duckweed for the past several seasons and it just keeps getting worse. He had made some attempts to control the aquatic weed this year with little success. I would imagine this isn’t the only pond owner who has been in this situation.

The first thing I tell people about fighting duckweed is that it isn’t an easy battle…I’ve never been a fan of people that over promise and under deliver!  If you are willing to put forth consistent effort and some money on product then this article is for you; if not you can move on to the next “easy” fix…by the way I’ll save you some time…there isn’t an “easy” fix for duckweed!

The product we recommend for controlling duckweed is called Tsunami DQ. Tsunami DQ has to be used in a very specific way in order for it to successfully control this pesky pond weed. Use Tsunami at the maximum dosage rate of 2 gallons per acre for consecutive weeks until the growth is gone. You will spray the product directly over where the duckweed is growing. Spray straight product if you can, if not add as little water as possible to get the coverage you need. Another step to successfully treat duckweed is to start early in the season. Don’t wait until the duckweed is sprawling across the entire pond.

In addition to using an herbicide we recommend changing the dynamics of the pond. You can use all the herbicides in the world, but it will be temporary unless you change the environment. Duckweed thrives in nutrient rich, still water. The first step to changing your pond is to get the water moving and start reducing the nutrients available in the water. Adding a fountain, aerator, or manually clearing trees and brush from around the pond are all ways to get the surface of the water moving. Using beneficial bacteria products will help reduce nutrients from run-off and over prolonged use will start to reduce the material on the pond floor.