Identifying Leaf Damage, Part 1 - Sunburn and Nutrition

My daughter sent me this picture a few weeks ago and asked what was wrong with her plants (and by the way, if you have questions too, feel free to leave them in the comments or send an email).

Damage to leaves can have a myriad of causes. Some causes are easier to figure out than others. Possible problems include insects and the variety of ways they damage leaves, sunburn - which is easier to figure out, and nutrition – either a lack of, or an overabundance of a substance.

This kind of edge browning is usually caused by a nutrition problem. It means your plant needs more or less of something. Different needs show up in different ways. I get tip die-back on one of my indoor plants but I don’t know what it is missing. If it bothered me more, I would try to fix it. But the plant just keeps sending out more leaves, so I cut off the ugly ones. My daughter's plant put on a bunch of new leaves that are beautiful, so it started to get whatever it was missing after she transplanted it.

OK, this is not the best solution, but this kind of problem needs more chemical knowledge than I have. So if you have edge browning, take a leaf in to someone who is trained, like the extension agents, and have them diagnose the problem.

It's easy to mistake nutrition issues and sunburn. This picture is sunburn damage on my grape plant, which lives on the hot and sunny south side of my house. Most of the leaves emerged and grew in the beating sun and could adjust. But part of this plant was shaded by an annual poppy and when I removed that plant, these leaves weren’t prepared for the summer sun. The result is sunburn. This browning seems to occur at random and the injury varies in intensity, but there are no holes. I didn’t expect it, but I won’t let other plants shade my grapes next year.