As I am nearing the completion of the outer portion, I would love your feedback. There are not enough people out there with any interest in this sort of thing to bounce ideas off, but maybe a few of the followers on here can offer some help.
1. In planning to insulate for winter, I'm not sure what to do about the perimeter where the wall meets the ground. As you can see, I laid the block the dumb way on its side so the whole bottom is open. What can I fill it with?