what insulation do i use for my walls in my craw space

The walls of a crawlspace are not normally insulated. Like an attic, the crawlspace needs to breathe somewhat in order to maintain moisture levels. I do recommend insulating the underneath side of the floor joists. Moisture barrier also needs to be installed appropriately. Remember that neither wood nor insulation should ever come in contact with the soil or concrete. Moisture barrier needs to "insulate" between the insulation and/or wood and the soil/concrete/stone works. Wet/damp insulation can breed mold. Concrete can wick moisture to the things you don't want to get wet. If you want to lessen the amount of cold that is allowed under your home, contact a "seriously good" local contractor for ideas