http://www.sialis.org :
1. Place large mealworms in a shallow plastic sweater container. Cut a hole in the top for ventilation and use a hot glue gun to adhere window screen to it to keep critters out.
2. Add 2-3" of bedding/food:
* wheat bran, or a 3:1 ratio of wheat bran to dried skim milk, or
* 4 layers: 1/4" layers of chicken mash (non-medicated) separated by layers of burlap or newspaper, or
* 10 parts oat or wheat kernels, 10 parts whole wheat flour, 1 part wheat germ or powdered milk; and 1 part brewers yeast.
3. For moisture, add a small wedge of cabbage or half a potato. Replace vegetable at least weekly or if moldy.
4. Ideally keep at around 80°F (room temperature is fine too) and around 70% relative humidity. Use a moistened sponge in a baggie/container (open side up above grain) for additional moisture.
5. Periodically (e.g., every 1 to 2 weeks) sift out beetles from bedding with eggs/tiny worms. Once worms are big enough, sift frass (waste) and bedding out once a month, dispose of in garden, wash and dry container, return worms and add new food.
Timetable and Lifecycle: Tenebrio molitor have an egg, larva, pupa and beetle stage. Depending on food and temperature, it takes about hundred to several hundred days for them to complete their lifecycle. Therefore, if you want worms in the spring, start your colony in November or December. For each 20 beetles, you should get about 350 adult mealworms in 200 days. Here is the lifecycle if the colony is kept at room temperature (~72 F.) I found it took much longer for the pupa to convert to the beetle stage.
