From my perspective, my roots are the primary channel for acquiring water. When the soil becomes excessively dry, my delicate root hairs cannot absorb the moisture I desperately need to transport nutrients and maintain turgor pressure in my cells. This dehydration manifests first at the farthest points from the roots—the tips of my leaves. The cells there die, resulting in the dry, crispy brown tips you observe. Conversely, if my soil is consistently waterlogged, my roots suffocate from a lack of oxygen and begin to rot. This damaged root system is then incapable of absorbing water at all, creating a similar state of physiological drought, and the leaf tips will also turn brown, though the affected area might feel softer.
Your intention to nourish me is appreciated, but an excess of fertilizer creates a hostile environment for my roots. Synthetic fertilizers are essentially mineral salts. When applied too frequently or in too high a concentration, they increase the salt content in the soil. This creates an osmotic imbalance where water is actually drawn *out* of my roots instead of being absorbed. This "fertilizer burn" directly damages my root system and disrupts my water uptake. The resulting stress, akin to drought, causes the tips of my leaves to desiccate and turn brown. Similarly, water high in dissolved minerals (hard water) can gradually lead to a buildup of salts in the potting mix, producing the same detrimental effect over time.
As a plant, I am constantly exchanging gases and water vapor with the air through tiny pores on my leaves called stomata. In environments with very low humidity, the rate of transpiration (water loss) from my leaves increases dramatically. If my roots cannot supply water fast enough to replace what is lost to the dry air, the leaf tips will dry out and die. Furthermore, I am sensitive to extreme temperatures. Placing me near a hot vent, radiator, or in the path of intense, direct afternoon sun can literally scorch my foliage, causing brown, burned patches on the tips and edges of my leaves. Cold drafts from air conditioners or open windows in winter can also cause cell damage, leading to browning.
Sometimes, the issue originates from microscopic attackers. Fungal pathogens, such as those causing leaf spot diseases, can invade my tissues. These often start as small, water-soaked spots that rapidly expand, turn brown or black, and can cause the tips of my leaves to wither and die. Bacterial infections can produce similar symptoms. These organisms thrive in conditions that are unfavorable for me, particularly on wet foliage. Overhead watering that leaves my leaves consistently damp, especially overnight, creates the perfect environment for these diseases to establish themselves and spread from the leaf margins inward.
