Beautiful cutting! I filled a hole with about 12 inches of crystal kitty litter, embedded the cutting, and then covered the top inch or so with compost and yard soil/leaves. I resisted the urge to water, although rain will eventually fall. (Crystal kitty litter--microporous silica pellets-- absorbs up to 30 times its weight of water, so hopefully this will be sufficient for this cactus to grow in a healthy way in a warm and wet climate.) So far, so good!