Should we encourage everyone to plant food in any vacant city lots ?

I don't know about "every" vacant lot, but I do believe that communitity gardens in urban areas is a great idea. I think that not only do the plants help the environment, but it also helps with the hunger issues that many inner city people face. I also think that communitity gardening is an excellent way to get to know your neighbors and build strong networks. It is also healthy for children to learn ways to interact with one another on a project to build teamwork skills. As for the last part of the question...it would have to be cabbage.