The small white things you think are Styrofoam are most likely pearlite. Its used for increasing drainage. Also used as an incubation medium for reptile eggs. You may want to cover the container as they like it moist. Also our native species take quite some time to mature and reproduce to the point of what you are looking for so i don't think you will have what you want by then. Also if you want to be able to regularly feed from it you will need a culture quite large. Medium sized rubber tote. Maby 30 gallons approximately.