Question: What causes my plants' leaves to be browned around their edges and at their tips?

Answer: Moisture stress. Those are the points farthest from the roots, so they dry out first and get water last. It's the same as with our ear lobes, fingertips and toes. Those are the places where our circulatory problems show up first. All of that said, moisture stress can be brought on by insufficient water, of course, but it can also be prompted by excesses of fertilizer, root or trunk damage, hot and drying winds and other environmental issues.