Hello, I have two questions: 1.) Why is "over-watering" typically said to be bad? Won't the plant simply take the water it needs and igorne any excess? 2.) Why is "standing water" bad for some plants? What is the reasoning behind this? I appreciate any help. Thanks, Greg
The reason for both is the same. Over watering will result in waterlogged soil, much like standing water. Plants take in oxygen through their roots. The air spaces between the soil particles hold the water with dissolved nutrients and air. If these spaces are filled with water, there is no air (oxygen) to be taken up by the roots. Some plants have mechanisms to tolerate growing in wet soil or underwater - many plants actually require those conditions. Also people should be aware that water left standing in trays under pots can cause this type of suffocation. While it appears that the water has drained from the soil, the surface tension creates a column of water, so to speak, connecting the standing water to the soil.
Another reason not to leave water in dishes under plants outside in summer is that standing water can serve as a breeding ground for mosquitoes.
