They say it takes around 1.5 acres to sustain a person. Farmland rents for around $300 per acre here, so $450 for the year to access the land you need for food. The food itself just kind of grows from that ground and sinks carbon to boot, so that's cool. A human emits carbon, so that's not exactly great for the climate, but you're probably going to do that regardless so we'll consider that a wash.

I don't know when you last tried growing a balanced diet, but I can tell you that growing anything as a crop is quite a way off "just kind of growing itself."