How long before mealworms turn into beetles?

Why are you giving them carrots and apples? Too good for some worms.

I just gave them some banana skin and tree leaves. They also eat fresh cut grass from the lawn. If you are going to run a mealworm farm to mass produce them for your reptile shop and the shop's customers, you probably do not want to feed them human grade fruit and veggie. It shots up the cost. These mealworms go for only $9.99 for each 1,000 worms from online vendors.