Any idea see here with the yellow and brown leaves ? At first I thought it might be the heat wave in SoCal but this looks bigger
Could be a deficiency of P or K …
Also could be a disease because it’s seems to be starting from the center veign of the leaf out …
P/k usually starts from the outside edges in I believe
Hopefully more knowledgeable help arrives soon
Check out this problem identifier to diagnose: Troubleshoot Plant Issues | Problem Identifier | Trifecta. If you’re on mobile, towards the bottom of the page you can filter by multiple symptoms. Hope that helps.
That is a small pot for a plant that size. It is easy for it to dry out, run out of nutrients, PH problems, etc. Next year you should invest in a 25 gallon for a more stable soil. Understand what I am trying to say?
Looks like the new growth is coming in fine, you could have over fertilized it a few weeks ago and you are seeing the damage now.