You need 0.5 to 1.5 acres per person for non-mechanized industrial argriculture. Nowhere with land that is truly arable enough for that is going to _sell_ you 1 acre at a time. In the U.S., you buy at least 40 acres at a time. In the U.S. Midwest, that's going to set you back (on average) $379,000. That's before you buy the equipment you need to be able to farm the land in the first place. Unless you industrialize and grow crops to sell to other people, you will not be able to afford the property taxes on the land to be able to keep it, either.
So, no, you cannot just go out and buy an acre and garden.
So, no, you cannot just go out and buy an acre and garden.