A drop of water to a root is good. It's good for the roots to grow and live and thrive. And what's good for roots is good for our plants and us humans too.
A good way to get a lot of drops of water for your roots is to buy a row boat (りょう). Then just row out to the middle of the lake and plonk all the roots right into the source!
Currently there are no similar looking kanji which exist in the WaniKani learning system