Title says it all, along with the photos. How do I fix whatever this is?

Watering is done from 1/2" PVC attached to the sides of the bed with 1/16" holes drilled in it. The pressure is adjusted so the water shoots only as far as the base of the plants, so the leaves are not getting wet. Even though we've had some rain recently, here in San Antonio we don't get much as a whole. It's been warm, bright, and relatively dry.

Overview pictures - too close together?

Tomato Detail: