Growing food is much harder than that.
Growing a few tomatoes or something is easy. But growing enough food to sustain yourself and your family is much more involved and requires a lot of training and experience.
Most people could likely do it. But it would take them 3-5 years of failures before they could reliably grow enough food for themselves. Probably more on the scale of a whole family.
Besides plants, you could have animals, and get milk and meat from them. Chickens for eggs and meat too.
It doesn't take too much land for it in my opinion. And if you live in a community that does that sort of thing, you could trade meat for tomatoes, and vice versa, or whatever, without relying on megacorps to give you your calories
Localism is the way
[1]https://www.statista.com/statistics/183648/average-size-of-h...
https://www.google.com/search?q=how+much+land+is+needed+to+f...
None of them I found credibly suggested less than an acre per person.
Check out the famous book, “Five Acres And Independence”. That was the basic size of a family farm in the USA a hundred years ago.