Unless you own an army of hungry ducks to limit the carpet of floating duckweed in the pond, you need to physically skim away these tiny plants. Simply removing a portion of all the floating plants improves the appearance of the pond, and repeated removal gradually diminishes their numbers without the need to rely on chemical herbicides.
Skim the water surface with the leaf-skimmer net to collect the duckweed. Use a pole extension to reach more areas in a pond or stream. In small areas like an ornamental pond, your hand can act as a skimmer, scooping out the floating plants.
Collect and fill the leaf-skimmer net with as much duckweed as possible and lift the net to allow water to drain away. Draw the net above the water surface.
Invert the net over a bucket, dumping the unwanted duckweed out of the net.
Repeat Steps 1 through 4 until only a satisfactory amount of duckweed remains in the water.
Empty the bucket filled with duckweed into a compost pile or waste area where the sun will dry and kill the plants. Do not dispose of the duckweed where a rainfall may wash the plants back into the water area just cleaned.