Hello, human caretaker. It is I, your mint plant. While I am a resilient and vigorous herb, the brown tips on my leaves are my way of signaling that my environment is not quite perfect. It is not a sign of imminent demise, but rather a request for you to listen closely. Let me explain the most common reasons from my perspective.
This is the most frequent conversation we need to have. My roots crave consistently moist soil, but not soggy, waterlogged conditions. When you allow my soil to become too dry between your waterings, the very tips of my leaves, which are the farthest points from my roots, are the first to suffer. They essentially dehydrate and die, turning brown and crisp. Conversely, if you are too generous and my pot sits in a saucer of water, my roots cannot breathe. They begin to rot, which prevents them from absorbing water at all. Ironically, this also leads to brown tips as the upper parts of my body become parched despite the wet feet you've given me.
As a plant, I am constantly transpiring, releasing water vapor through tiny pores in my leaves called stomata. If I am living indoors near a heating vent, a radiator, or in an air-conditioned room, the air can become very arid. This dry air pulls moisture from my leaves faster than my roots can replace it. The delicate leaf margins and tips are the most vulnerable to this kind of moisture loss, resulting in those dry, brown edges you see. I much prefer a more humid environment.
I am a fast grower and that requires energy. The soil in my container has a limited supply of nutrients. When they are depleted, I cannot produce the healthy, green chlorophyll needed for my leaves, and the tips may brown as a sign of hunger, often accompanied by an overall pale green or yellowish color (chlorosis). On the other hand, your kindness in feeding me can sometimes be too much of a good thing. An overabundance of mineral salts from fertilizer builds up in the soil and can actually burn my root tips. This damage then manifests as brown burns on the tips of my leaves above the soil.
My roots are naturally expansive and exploratory. If I have been living in the same pot for too long, I may have become pot-bound. This means my root system has grown so dense that it has circled the inside of the pot and can no longer access water and nutrients efficiently. Even with your diligent watering, the root ball may shed water down the sides of the pot without absorbing it, leaving the core of my roots dry and causing my leaf tips to brown from thirst within my own home.
