We live in a condo now, so no garden here. But I have always kept at least a 2 to 3 week supply or more of food, including dry and canned beans. As campers, we also have propane stoves (yes, plural), extra propane, we do have a small generator, but it's not going to last for very long, lots of camping lanterns, flashlights, an emergency radio.
We should get water to keep, but with us, space is a big issue. If we get any warning we can fill the van's tank and live off that for a while. Or as they used to say, fill the tub up...I haven't seen those kind of emergency instructions in a long time.