The duckweeds (genus Lemna) and related genera of the duckweed family (Lemnaceae) are the smallest flowering plants known. Individual plants consist of a single, flat oval leaf (technically a modified stem) no more than ¼ of an inch long that floats on the surface of still-moving ponds, lakes, and sloughs.
To grow duckweed, you need a container with clean water, a suitable light source, and a small amount of liquid fertilizer; simply add duckweed to the water and place in a well lit area. Keep temperatures between 60-80 degrees F. Your duckweed will go crazy!