Duckweed Control

Duckweed control can be very challenging. Duckweed is a free floating plant that will completely cover the top of your pond with thousands of bright green 1/8 inch leaves with a small root hanging from the plant.  Duckweed prefers to grow in ponds next to woods and ponds that have lots of nitrogen and phosphorus. 

In order to have an effective duckweed control strategy you need to know the environment duckweed thrives in.  Duckweed thrives in ponds that receive very little surface movement.  That is why ponds near or surrounded by woods are prone to duckweed because there is very little natural surface movement from the wind.  Duckweed also thrives on excessive nitrogen and phosphorous, which typically comes from fertilizer run-off.  The use of beneficial pond bacteria can help neutralize nitrogen and phosphorous.  Usually duckweed will disappear from the surface of the pond on it’s own in the fall because of the built up starch and the weight of the plant.  However, when the plant starts photosynthesizing again in the spring they will resurface again.

There are very few duckweed control methods.  The first is manually removing with elaborate skimming devices, however, disposing the plants is difficult.  This method is labor intensive, time consuming, and sometimes not effective. 

The most effective duckweed control option is to chemically control the plant.  Diquat (Tsunami DQ) can effectively control duckweed with minimal restrictions on recreational activity.  Tsunami DQ is a contact herbicide, meaning the product has to come in contact with the plant in order to kill it.  Spray application is usually the best way to distribute the product into heavily infested areas and you will need more than one application to effectively control duckweed.

For more information on duckweed control Contact Sanco.