I've got a 2nd year Northern Brewer plant in a large container. Last year the leaves started turning brown on the edges and eventually started falling off mid-season. This pic is about 5-6 weeks since they sprouted this year and I'm already seeing them start to get a few brown edges/spots. When they first broke ground I gave them Miracle Gro Quick Start fertilizer (properly diluted), it appears to have a little bit of everything as far as nutrients go. I'm also growing in Southern California, and while it hasn't gotten HOT yet it did last year and I had to water every other day.
Any ideas on the brown leaves? Too hot? Too much direct sun? Not enough fertilizer? Too much fertilizer?