I've hardly been fertilizing at all, but I have been following the directions on Jack's Classic fertilizer, made by Peters, when I do. I don't have any pH testing stuff, but I'd be surprised if that's the problem.

There may be some sort of grub munching on the roots of my plants, but I was pretty sure I got rid of that problem. Lower leaves on some of my plants are periodically dying for no reason again, so they may still be around.

I'll try mixing a little epsom salt with my next watering and see if that helps.