Help,what is happening to leaves

[mick5500]

This is my first year doing all container growing after moving to high desert(Victorville, CA) and a lot of wind.
Tomato's and hot peppers about 20 right now. I did buy all from a couple stores(Home Depot) in 3 inch pots. Bonnie and some local organic.
They are all in good planters( miracle grow. Kellogg potting mix) and have them above ground on stones 4 inches high with bug spray surrounding them at ground level, so nothing coming from the ground.
They are growing okay but now the leaves are starting to die on some of them.
Some are healthy but not growing much.
Any ideas,

Thank You