A few months back I decided to try to grow some crops (lettuce) to see if I could do it in case the worst case scenario ever happened(total collapse) I used no fertilizer and just let the rain water my plants. All I did was clean the ground when any grass grew too close. I did this all in my back yard and did it in a way that every person who knows nothing about growing crops would do it. (planting them too close together, not tilling the soil before planting, ect.) Out of 11 plants, only 7 turned into heads of lettuce. Some reached a certain size and just stopped growing and some didnt quite turn into a head of lettuce. There were many bugs on the first few layers, but once I took those layers off, the lettuce was clean, fresh and edible, but very very small. I ate the lettuce a few minutes after picking it and it was the crunchiest, most fresh lettuce i ever ate. Here is what the lettuce that grew into heads looked like all cleaned up. Its pretty funny, but was a nice exercise on how city folks crops will look if we end up in a mad max type world one day.