In early June, I planted Osteospermum in my planter boxes. They get 6-7 hours of full sun. I water daily in the mornings. Lately, I have noticed the leaves in the center (inner core) of this annual are brown and wilted. Is this from too much water or too little or something else? Please advise.
Osteospermum is a cool weather plant. It goes somewhat dormant in hot weather. It is semi-succulent, and does not do well in constantly wet soil. If the plants were mine, I'd water thoroughly then allow to day somewhat before watering again. Brown, crispy leaves in the core of the plant is a common occurrence. You are giving them enough sun. I'd hold off the water some and wait for cooler to let them "show their stuff". (If they get too leggy, cut them back.)