Duckweed Control - Treat Early for best results

3 Quick Tips for Maximum Duckweed Treatment Results

If you've ever had a severe duckweed issue you probably know that a clear pond surface one day can be totally covered in duckweed within a week.  Here is why - Although duckweed does produce a seed, the vast majority of it's reproduction is by cloning or production of daughter plants.  Each individual duckweed plant can produce a daughter plant in less than 24 hours.  This generates exponential growth of the duckweed population that expand to cover a pond very quickly!  

As water temperatures increase in early spring dormant duckweed plants that settled to the pond bottom in the fall float to the surface and prepare to multiply.  This is the best time for a vigilant pond manager to take the duckweed infestation head on!

Emerging Duckweed

3 Essential Duckweed Control Strategies 

  1. Treat in late spring.  Watch for the dormant duckweed plants to surface.  They typically will begin to appear along the pond edge.  The number of visible duckweed plants will slowly grow during this phase.  Observe the pond surface daily and when the duckweed population appears to stablize, you've reached the ideal treatment time.  At this point most, if not all, of the dormant plants have surfaced but they have not entered their exponential multiplication phase.  We recommend treatment with a combination of Ultra-Pondweed Defense (diquat aquatic herbicide)Algae Defense (copper complex), and Treatment Booster Plus (surfactant).  For each 2,500 square feet of duckweed/water meal to be treated mix 16 ounces of Ultra Pondweed Defense, 1 quart Algae Defense, and 4 ounces of Treatment Booster Plus with 2 gallons of water in a portable sprayer.  
  2. Eliminate every duckweed plant you can find!  Spray the solution above on every visible plant.
  3. Follow up 2 weeks later.  You missed a few on the first treatment.  It's inevitable!  Don't let the few remaining plants regenerate and take over!

Non-chemical Duckweed and Water Meal Management

Since duckweed and water meal are rapid reproducers, non-chemical management is difficult.  However, floating fountains and bottom aeration systems do provide some control because the small plants prefer calm, flat water.  Installation of one or more floating fountains or a bottom aeration system will create small, choppy waves on the pond surface that can discourage duckweed and water meal.  This approach is typically more effective for water meal than for duckweed simply because of the difference in plant sizes.  

May 9th 2016 Jonathan Klotz

Recent Posts