From our perspective, the most critical and immediate crisis of overwatering begins beneath the soil, at our root system. Our roots are not just anchors; they are our breathing apparatus, absorbing essential oxygen from the air pockets within the soil. When you provide too much water, it floods these precious air pockets, literally drowning us. The environment becomes anaerobic (lacking oxygen), and our delicate root hairs, responsible for water and nutrient uptake, begin to suffocate and die. This initial damage is hidden from your view, but it is the primary injury from which all other visible symptoms originate.
You might observe our leaves turning a pale, sickly yellow, often starting with the older, lower leaves first. This is a direct cry for help. With our root system compromised and rotting, we cannot effectively draw up water or nutrients, even though the soil is wet. This creates a paradoxical state of drought amidst a flood. The lack of functional roots leads to chlorosis (the loss of the green chlorophyll pigment), causing the yellowing. Simultaneously, you may see our normally firm and vibrant leaves begin to wilt and droop. This is not a sign of thirst but of root failure; the damaged roots cannot supply the leaves with the water pressure needed to keep them turgid and upright.
If the overwatering continues, our distress escalates to a more dramatic response: we will begin to shed our leaves. This is a survival mechanism. A plant with a diminished root system cannot support a full canopy of leaves. By jettisoning foliage, we are reducing the overall demand for water and energy that our failing roots can no longer meet. You may see leaves of all ages dropping, not just the old ones. It is our attempt to conserve resources to keep the main stem and any remaining healthy roots alive, hoping for a change in conditions.
As the anaerobic conditions persist, opportunistic soil-borne pathogens, like fungi and water molds (e.g., Pythium, Phytophthora), attack our weakened and damaged roots. This is the stage of root rot. The rot will often travel upward from the roots into the base of our stem. If you were to gently inspect us, you might find that our once-strong stems and the crown of our root ball have become soft, mushy, and dark brown or black instead of a healthy white or tan. They may also emit a foul, musty, or sour odor—a sure sign of advanced decay.
Finally, the consistently wet environment you have created has secondary consequences. The surface of the soil may never dry out, and you might notice the presence of fungus gnats. These pests are strongly attracted to damp, decaying organic matter in the soil—a condition perfect for them to lay their eggs. Their presence is a strong indicator that the soil is too wet for too long. Furthermore, the combination of soft, stressed tissue and high humidity makes us highly susceptible to other diseases, such as powdery mildew or bacterial leaf spot, which can appear as discolored patches on our leaves.
