We are no longer raising monarch caterpillars indoors, just letting things happen naturally.
Currently there are more than eleven pots of native milkweed growing in the backyard.
Some have been growing for two years, going dormant in the late fall, when I cut them down to the level of the soil. Other milkweed plants are from last year, also growing back after the dormant winter season, when they were cut down to soil level.
The monarch butterflies seem to favor the narrow leafed milkweed Asclepias fascicularis as the host plant to lay their eggs. The leaves are definitely softer and tenderer than the Davis milkweed Asclepias speciosa 'Davis'. We have both kinds growing in pots.
And here are some of those babies, all in their fifth instar, eating their fill before morphing into pupae. I counted fourteen caterpillars this time around.
We have bamboo arches stuck in the soil of the pots, some acting as bridges into neighboring pots so that the caterpillars can go to another pot for more food, should they gobble up the leaves of the plant where they started their lives.
Sometimes the caterpillars like to hang out on the arches where they rest a day or so before they shed their skin, growing larger into their next instar. They favor smooth surfaces to do this.