Buying crickets every few days to feed to my bearded dragon gets expensive, and I hate going to the store. Is it possible for me to breed crickets?
Yes, and it's actually really easy.
You will need are two containers. A large container for the adults, and a smaller one for the babies. I use two plastic storage bins.
You can fill the containers with torn up egg carton, which is what the stores use if you peek into their containers. Or even crumpled up newspapers. This gives the crickets places to grab onto and hide. It makes them feel safe, and keeps them safe from each other.
Crickets will eat each other if they don't get other food first. So, it's important to keep plenty of food available. Since you're wanting to feed them to your reptile, take this opportunity to gut-load the crickets. You can make your own formula with vegetables and supplements, or use a commercial cricket food. I use Fluker's Cricket food (Both the orange food cubes and yellow thirst quencher) because it's incredibly convenient.
When you purchase the crickets, you'll only need about 30 or so large crickets. Try to get as many females as possible, as at that size they will no longer be at the point where they will need males since female crickets store semen. Females can be identified by their ovipositor (the thing that looks kind of like a stinger) which is what they use to lay eggs in the ground. Here's a picture of a female cricket for reference:
In the bigger storage bin, with the adult crickets, keep a small container of clean dirt for egg-laying. You can use topsoil, or I use Exo-Terra coconut bedding. Do not use potting soil because the additives can be harmful, and don't use dirt from outside, as it can have been exposed to chemicals and have parasites.
Keep the dirt moist, so that any eggs laid do not dry out, and simply wait somewhere between one to two weeks for the crickets to finish laying their eggs. When you're ready to incubate the eggs, take the container of dirt, and move it over to the smaller storage bin. The point of separating the adults, and babies, is because the adults will eat the babies, and even eggs if they're left in there with them for long enough.
Now, it's important to remember baby crickets are tiny. They're microscopic when they're first born, so you probably won't even notice that they've hatched at all. Leave some pieces of cricket food on, or near, the soil for them to find when they first hatch, that way they don't starve before you even see them.
Also, since they are so tiny, they can climb up nearly anything. Their legs can fit in the imperfections of plastic, glass, and especially the silicon of fish tanks. It's best to put a strip of packing tape around the inside of the container, a few inches below the top. For whatever reason, the packing tape is smooth enough that they can't climb up it.
Here's a poorly made picture of how the tape should go:
It will take a couple weeks for the baby crickets to grow. But once your colony is established, it will grow like crazy. Each cricket lays about 30 eggs at a time. Put the container of dirt back into the large adult storage bin, so they can lay some more eggs, and if any crickets in the baby storage bin get to be about a half of an inch in length, you should move them over to the adult storage bin as well.