A recent show on the BBC featuring Mexico City's Floating Gardens of Xochimilco made me curious about an ancient gardening technique called chinampa. I remembered that a while back, one of our Daily Dirt readers had also mentioned these Aztec gardens in reference to raised bed gardening. It's also similar to a technique called lasagna gardening.
Dating back at least 2,000 years, these gardens were developed by the Aztec people in response to their surroundings--marshy wetlands and shallow lakes--in order to grow much of their food. Interestingly, it was a form of land reclamation for horticultural purposes rather than for land itself as was common practice in US cities like Washington, D.C., San Francisco, and New York at one time, and this gardening technique is still used today. Of course, these floating gardens were not really floating, but constructed by digging canals in the marshy land and using the mud or lake sediments to build a mound of land where they could plant and grow crops.
These garden plots measured between 15 and 30 feet wide and were as much as 300 feet long. The sides of the mound were secured using a wattle type fence system and willows were typically planted to prevent erosion. In addition to bottom sediments, decaying vegetation (i.e organic matter) was also used as part of the mound building process. As a result these garden plots were nutrient rich--supporting numerous crops all year long such as maize, beans, squash, tomatoes, and other crops integral to the Aztec diet.