Check your state laws before using duckweed. It is illegal to possess in many states. It is highly invasive. If it is legal, please be sure to boil, bleach, or dry it before disposing of excess. A single leaf can quickly multiply to cover ponds and lakes, choking out native plants.

If it is legal, it is a very effective nutrient exporter. It will help keep nitrates down. It also offers frogs and toads a sense of security by allowing ample hiding space. It is fairly easy to keep in check by netting out small amounts daily.