In the ruins of an old storage building, young urban farmers in Mexico City’s Roma District are experimenting with how to grow efficiently, and easily, in a small space. They share their experiments in square foot gardening, DIY vertical gardens, permaculture, herb spirals, hydroponics, rainwater catchment, and vermicomposting.
When most people think of gardening, soil comes to mind. But plants don’t actually require it to survive. They mostly need the nutrients and minerals in the soil. Plants can grow in water, gravel, perlite, rice hulls, pine bark, cedar shavings, and other mediums, or even suspended in air.
The science of soilless gardening is called hydroponics. It may sound like something devised in a modern laboratory, but it’s been around for thousands of years. The essential ingredient is an oxygenated mineral-nutrient solution that’s circulated through plants’ roots.
Some scholars theorize the ancient Hanging Gardens of Babylon, one of the Seven Wonders of the World, was a hydroponic system. The Aztecs grew maize, squash, beans, amaranth, tomatoes, chili peppers, and flowers in high-output chinampas, or floating gardens, which were hydroponic systems. A traditional hydroponics system is still in use on Myanmar’s Inle Lake, and similar systems probably existed in ancient India, Greece, China, and Egypt.
In the early 1600s, the British scientist Sir Francis Bacon, father of the scientific method, conducted formal research on hydroponics, which he called “water culture.” Laboratory experiments continued into the 20th century. In 1937, William F. Gericke applied the experiments to large-scale commercial applications, and the modern hydroponics movement was born.
Today many people identify hydroponics with marijuana growers, who’ve made use of the technology. But much of the world’s greenhouse produce is now grown in hydroponics systems, including some of the lettuce, tomatoes, herbs, and veggies in many supermarkets’ refrigerated cases.