Cities can give property owners a property tax credit for growing food whether in ground or in containers. A greater tax credit can be given for those who generate income through their efforts. They may have to change zoning to allow for market gardens on residential property. A municipal
composting facility can recycle organic waste and
sell it at cost to the urban growers.
Cities can create jobs by paying urban farmers who live in the city to raise food on school property. The funds being spent to purchase food from vendors can pay the farmers' salaries. This could be done at any municipal facility that has land or other space for container gardens and purchases food.
Heck, I've got a whole program I'm working on formalizing for Atlanta that a city could implement and spur the
local economy while localizing it's food. I'd be happy to talk to you about it. Perhaps you could present it to your city council if you like it.