Just find some ants living in soil, dig them up, and dump them in. The advantages are that it is an easy and inexpensive way to keep ants, and it works. The disadvantages are that you must find ants to put into the jar, and the ants may escape while you are changing food or watering. You can alleviate this problem by placing the jar in a shallow pan of water to serve as a moat. Chances are good that the queen escaped, so as with the commercial ant farm the ants will not last more than a few months.
Plaster is poured into and shaped in various-sized containers or terrariums.
Simply add ants and keep the plaster moist. In plaster nests no soil is added, so the ants won t tunnel. If you are lucky enough to find a queen ant, she will do well in this type of nest. The disadvantage is that the ants are likely to climb out of terrariums, so you will need to coat the top insides with petroleum jelly or mineral oil. This provides a chamber for the ants to live in.