overwater
verb /əʊvəˈwɔːtə 
/ [with object]
/ [with object]Water (a plant, sports field, etc.) too much: your cutting needs some water, but make sure you don’t overwater it...
- The second year I compensated and overwatered the plant.
- At the same time, be sure your plant is not getting too much water, either by overwatering or being planted in a soil that does not properly drain.
- Some parts of these slightly rolling irrigated fields were being overwatered by as much as 20 percent.