If your soil is overly wet, you'll have to water it more frequently. While your plant's roots require both water and oxygen to thrive, if they're languishing in waterlogged soil, their oxygen intake decreases, making them more vulnerable to disease and insect damage, and ultimately leading to death. As an alternative, if you have too much air in your soil, your plants won't have time to soak up the water. Because of this, your plant's roots will become dehydrated, leading to its eventual death. Plants that receive insufficient water are just as vulnerable to disease and insect damage as those that receive excessive amounts of water.