Better get busy making some raised beds.
Good luck with feeding yourself from a small garden. I have a bit of a green thumb. Planted 20 shallots in a grow box just for a test. Got 37 shallots back. At the rate wife uses shallots, I would have needed a dozen grow boxes.
I love having a few tomatoe and bell pepper plants, maybe an eggplant or two, a couple of squash, a scattering of lettuce for the few months it will grow withouth bolting. But anyone that thinks they can grow their own food without acreage available is nuts!
If you think the SWHTF, stock up on freeze dried, etc.
Plan on snacking on the occasional liberal or looter.