From my perspective, my leaf edges turning brown is most often a direct cry for help regarding water. My roots are delicate and prefer consistently moist, well-drained soil. When the soil becomes too dry, I cannot draw up enough water to supply my large, thin leaves. The cells at the very edges, which are the farthest from my veins, die first, resulting in that dry, crispy brown margin you see. Conversely, if my roots are sitting in waterlogged soil, they begin to suffocate and rot. A damaged root system is just as ineffective as a dry one; it cannot absorb water and nutrients, leading to the same symptom of browning leaf edges as my upper parts become dehydrated despite the wet conditions at my base.
My leaves are my solar panels, but they can get too much of a good thing. Intense afternoon sun, especially when coupled with hot, dry wind, can simply scorch my foliage. This is a physical burn where the leaf tissue dies, creating brown, crispy patches, often starting at the edges. Furthermore, a sudden heatwave can accelerate water loss through my leaves (transpiration) faster than my roots can replenish it, causing drought stress even if you've been watering. This is particularly true if I was recently moved or if a protective shade source was removed, exposing me to more direct sunlight than I am accustomed to.
What you feed me and what is in your water can also cause my leaf tips to brown. I am sensitive to excessive salts, which can accumulate in the soil from over-fertilization. These salts draw water out of my roots, creating a reverse osmosis effect that dehydrates me from the inside out, and the leaf margins are the first to show this damage. Similarly, water high in dissolved minerals, like chlorine or fluoride, can slowly build up in my system. As these chemicals are transported to the edges of my leaves, they become toxic to the tissue, causing it to die back and turn brown.
While less common than the issues above, my overall health can be compromised if my soil chemistry is not to my liking. I famously prefer slightly acidic soil. If the pH is too high (alkaline), I struggle to access certain vital nutrients like iron, even if they are present in the soil. This leads to interveinal chlorosis, where leaves yellow while the veins stay green, but in advanced cases, the edges can also brown and die. A consistent lack of key nutrients, particularly potassium which helps regulate water movement within my tissues, can also manifest as browning leaf margins as my systems begin to fail.
