When I had crickets, a pet shop boy recommended tropical fish flakes had all the nutrition they need. Since roaches and crickets are supposedly related, I give my German roaches the flakes and also a brown powdery vitamin supplement made for crickets (Fluker's) brand. Since neither are fresh food, they won't go bad while your'e away. Fluker's also makes cricket quencher water gell which will hold water better than cotton balls and you don't have to worry about them drowning in it. All 3 items are in most pet shops. Not sure if it's good for ALL roach species, but my Blabberous Disorderous did good with the stuff as well as my German.