To overwater means to give a plant too much water, more than it needs to stay healthy. When you overwater a houseplant, the soil stays soggy instead of just moist, which can actually harm or kill the plant. The roots need air as well as water, and when soil stays waterlogged, roots can rot and the plant can suffocate.

Many beginning gardeners overwater their plants because they think more water means more care. But plants are like people: they need the right amount, not the maximum amount. A cactus needs very little water and can die quickly if overwatered. A tomato plant needs regular watering but still wants the soil to dry out a bit between waterings.

You can tell if you've been overwatering when leaves turn yellow, the soil smells musty, or the plant looks droopy even though the soil is wet. The tricky part is that an overwatered plant often looks similar to an underwatered one, with both wilting and looking sad. The difference shows in the soil: stick your finger in. If it's wet, you're probably overwatering. If it's bone dry, you're underwatering.