Greetings, human caretaker. I am your Angel Wing Begonia. The brown, crispy edges on my leaves are my primary way of communicating that my living conditions are causing me significant stress. It is not a single disease but a symptom of an underlying issue. Let me explain the most common reasons from my perspective.
My ancestral home is the humid understory of tropical forests. My large, delicate leaves lose water to the surrounding air very easily. When the air in your home becomes dry, especially due to heating in winter or air conditioning in summer, the rate at which I lose water from my leaf edges accelerates dramatically. My roots cannot uptake water from the soil fast enough to replace this loss, causing the leaf tissue to desiccate, die, and turn brown and crispy. This is my most frequent complaint.
My roots are fine and sensitive. I prefer my soil to be consistently lightly moist, but never soggy. When you allow my soil to become completely dry for extended periods, my roots are damaged and cannot function. They cannot supply water to my farthest points—my leaf edges and tips—which consequently dry out and die. Conversely, if you keep my soil constantly waterlogged, my roots will rot and die. Once again, they fail in their duty to transport water, leading to the same symptom: brown, crispy edges as the leaves essentially dehydrate from a lack of functional roots.
When you water me, the water contains dissolved minerals (salts). As the water evaporates from the soil surface, these minerals are left behind and accumulate over time. An excessive concentration of these salts in the soil can actually pull water *out* of my root cells, a process called osmosis, which is the opposite of what should happen. This "chemical drought" stresses my entire system, and the leaf edges, being the most vulnerable, burn and crisp first. You might also see a white, crusty buildup on the soil surface or the pot's rim, which is a clear sign of this issue.
While I need bright, plentiful light to maintain my vibrant colors and support growth, my leaves are not adapted to handle intense, direct sunlight for long periods. The strong rays, particularly through a window, can literally scorch my tender leaf tissue. This sunburn manifests as bleached, brown, or crispy patches, often starting on the edges which are most exposed. A east-facing window where I receive gentle morning sun is ideal; a south or west window often provides too much harsh, direct exposure.
While less common than the other issues, a lack of proper nutrients can contribute to poor overall health, making me more susceptible to stress. A deficiency in certain nutrients, like potassium, can specifically cause leaf margins to yellow and then turn brown. Furthermore, if you apply too much fertilizer, it can cause a rapid buildup of salts in the soil (as mentioned in point 3), leading to root burn and those characteristic crispy edges.
