6. Dig a Root Cellar. Root cellars can be a valuable, off-grid way to store your yearly crop of potatoes, onions, parsnips, carrots, and other root vegetables. A root cellar doesn’t necessarily have to be a large underground room, it can also be more of a smaller trench. There are many books and resources out there highlighting all the how-tos of constructing your own old-fashioned “refrigerator”.