If the real shit happens you'll need a property of land to be able to produce food. Stocking food for 1 month lasts only for 1 month. What if things last longer? Well in that case you would depend on your governments. I hope everything will be fine and we won't need that.
It would be more practical and cost effective for most just to stock 1 year supply of tinned food. If real shit happens, and goes for that long, you plantation will probably be raided by hordes of hungry and violent people way sooner.
Many assumptions that people do make when they consider some sort of "real shit" scenario are wrong or not the really shitty scenario conditions. Ie: Will you have enough water supply to keep growing your veggies? Food to feed your livestock? Will you be able to protect your "land"?
So Keep it simple: Have resources ready to use that don't depend on external resources or conditions. Tin food is probably the best and you have ages to consume it even if you overstock. So no real extra cost here. Heck, maybe you will even manage to get a quantity discount!
Anyway, I still think this levels of paranoia are too much unjustified... but if you want to be "prepped", do it the right way. The simpler the better.