The key to the whole system is the fertilization method. Chemical fertilizers can be expensive and often don't work well. The recommended fertilizer for container farming is actually urine. The decaying leaf matter in the bottom of the container breaks down the urine quickly, so that the smell is reduced and germs do not survive in urine. Also, most importantly, urine is obviously inexpensive and quite easy to produce. Due to the decomposition process happening inside the container, plants proved to be more pest resistant and resilient to disease as well.
The project has proven extremely successful in creating a form of farming which is cheap, self sustaining and accessible .
1. Willem Van Cotthem. "Mexico: Container Farming in Slums," Desertification Blog, posted on February 16, 2008, http://desertification.wordpress.com/2008/02/16/mexico-container-farming-in-slums-mmc-journey-to-forever/ (10/04/09 10:30 am)