Several concerns:
Check your plants for pests...carefully.
Did you buffer your coco before you planted in it?
Why did you add vermiculite...this is going to go against your coco's ability to drain. Don't change it now, being you're growing autos, but you may want to revisit this after your run and either go straight coco or add perlite...but vermiculite, in this instance isn't really your friend.
Elaborate on what you're feeding schedule is...give the details, as to pH, how often you water / feed, feed strength, etc.