These are otherwise known as Victory Gardens, which were popularized in the World Wars. The purpose was to increase food production without requiring packaging materials, transportation hardware, and fuel that would otherwise be devoted to war efforts. Garden efforts would also boost morale at home. I think there are lots of different layouts. There is one at the Smithsonian National Museum of American History. The impact of these was quite large at a time when there weren't any supermarkets with a vast range of quality produce. These were the days when home food production could be considered a necessity rather than a hobby.