As an indoor plant specialist, I am often approached by random people asking for advice. ‘Why is my plant dying?’ they will ask in a distraught manner. ‘I am a black thumb. I kill everything; please help me!’
I don’t even have to see the aforementioned plant to enlighten the distressed individual(s) as to the most important tip of interiorscape care. I tell them that 99% of indoor plant deaths are caused by overwatering.
When plant stress is apparent, most people water more; almost impulsively. For instance, if the plant’s leaves fall off, it must need more water. If the plant is wilting, it must need more water, etc. Oftentimes people are so busy paying attention to leaves that they forget about soil (and roots) in the process. This can prove to be harmful and even fatal as excessive watering causes the plant to drown. Think about it: if roots are flooded, they will rot and reject absorption of oxygen, nutrients, and water. When this occurs, leaves will fall off and wilt as roots are too damaged to function properly.
Much of the guess work that pertains to watering is reduced by a soil probe, which is a sharp metal stick with grooves near the end. For the most part, your finger will suffice as a moisture meter in small plants. When this is not possible (for larger plants and trees), insert the metal probe into the soil and pull it out. If dirt falls of, water evenly; however, if dirt is sticky and muddy, do not water! Wait another week and check again.
Please note that probes are a suggestion (a strong recommendation) and not a definite rule. For instance, a hydrangea needs water every day. Also, be aware of other potential factors concerning the declining health of your plant. Has the temperature changed recently? Have you moved your plant into a new location? Does it have adequate lighting? Does it have a pest of some kind? All of these considerations are useful in determining reasons for plant shock and death.