The easiest way to grow more of your own calories is to focus on roots like potatoes and carrots. With yields of up to 200 calories per square foot, you can break your reliance on the grocery store with just a few seeds or starts and a shovel. Most root crops are easy to store through the winter and require no special harvesting or processing equipment.
So why don't we all grow roots? To keep the tubers happy after harvest, these crops need a cool, damp storage spot like a root cellar. This book walks you through building a root cellar out of a junked fridge for $10, and also presents some slightly-higher-cost options for winter storage. Other highlights include tips for growing storage vegetables and feeding those roots to your family or your livestock.
Self-sufficiency begins with the potato!