You reasonably can't. Most people don't live in rural areas with enough farm land, and even if you have farm land that can grow enough (both in quantity and variety) crops to feed your family, which is a rarity in itself, you still need to deal with property taxes, expenses for maintaining your farm house and equipment, school expenses...
Face it, there is no way of living "off the grid" to a reasonable degree.
Face it, there is no way of living "off the grid" to a reasonable degree.