Hi! I live in SOCAL and up until now my sweet natahlie dahlias had been doing great, but now the edges of almost all the leaves are turning brown and crispy! It's happened pretty quickly.
It's in a terra cotta pot with drainage, I've given it low nitrogen fertilizer, and the dahlias next to it (in their own pots) don't have the same problem. The pot gets full sun with some periods of shade in the morning and late afternoon. I thought at one point the pot may have been overwatered but I let it dry out. I also make sure to only water at the base.

Any thoughts on how to save it??? I don't see a ton of new growth so I'm concerned.

There are some leaves on one of my dahlias that look like that. I thought it might be sun damage but I found a lot of thrips hiding down inside the petals of a bloom. They eat and lay eggs on the underside of leaves. The ones I found were black and so tiny I had to use a jeweler's loupe to identify them. Some are white, red or a yellow-green color. I broke off the damaged leaves and gave the plant a good spray of water. Can't say for sure that thrips are my only problem. It could also be from all the hot, humid weather we've had. I'd suggest checking "dahlia leaf damage" on google images.

Hi there! Did you ever get a reason or resolution to this? I just noticed this on one of my dahlia plants and it sounds like the same situation (pitted dahlia, the others I've planted don't show this - at least not yet!)