We either use an orthotic grade memory foam padding called Poron (it's made in the U.S. and was originally developed for NASA!) or a cork/rubber blend.
In general, we use firmer padding that gives you real support because in our experience, when it starts out soft and squishy, it quickly goes flat and doesn't give the bounce back needed to support and mold to your feet.
In the Garden sneaker, our insole has a gentle arch support as well to keep the ankle properly aligned because the shoe is nice and flexible. But this insole is also removable if you have any preferred brand of insole you like to wear in your sneakers.
For all of our styles, you could also request for the insole to be removable as well if you'd like to use your own. But on all of our shoes, at least one layer of the memory foam is directly applied on the midsole (that is the backbone support of the shoe that the shoe is lasted onto) so regardless of insole used, there will always be an additional layer of support on the midsole board.