Supersonic

HELP! Edges of leaves turning brown starting on sides of leaves all over plants , this is an outdoor grow in planting mix that was purchased from a local soil place. It’s got lots of turkey dung and decomposed wood. I generally water every other day and haven’t given them any nutes for about a month because I thought maybe it was nutrient burn. I have a few plants in 55 gallon barrels and several in the ground. All have the problem. It has been very hot here, regularly over 100 degrees but I run a giant porta cooler swamp cooler on them anytime it gets close to 100. I have blue dream, strawberry banana and pink Hawaiian and they all look the same. They are growing extremely fast though and new growth on top looks healthy and the further down the plant you go the worse they get. Any ideas??