Records show that plants have been grown without soil for many thousands of years. The hanging gardens of Babylon used hydroponic techniques. Marco Polo observed these systems in China. To escape enemies, the ancient Aztecs reportedly took to the lakes and maintained large floating rafts woven of rushes and reeds on which they raised food crops. In 1699 the British scientist John Woodward grew plants in water to which he added varying amounts of soil. He concluded that while there are substances found in soil that promote plant growth, the bulk of the soil is used for support. By the late 1800s, horticultural scientists were successfully raising plants in solutions of water and minerals. The modern science of hydroponics began in the 1930s when Dr. W. E. Gericke at the University of California raised tomatoes and other crops on floating rafts, applying the earlier principles in a commercially successful way. He coined the name hydroponics as he worked with water. What more can your students discover about the history of soilless growing?
Hydroponics, in its simplest form, is growing plants by supplying all necessary nutrients in the plants' water supply rather than through the soil. The word derives from the Greek root words hydro and ponics, meaning water working. Growing plants hydroponically helps gardeners and farmers grow more food more rapidly in smaller areas (greenhouses, living rooms, classrooms, and rooftops, for instance) and to produce food in parts of the world where space, good soil, and/or water are limited.
When youngsters explore how to grow plants hydroponically (without soil), fruitful questions bloom: How can we provide support for plants without soil? How do plants grown with just water and nutrients compare with plants grown in soil? How can we get the tallest plants using a hydroponics setup? These types of questions can lead to active investigations and problem solving. Record-keeping becomes a natural outgrowth of these endeavors. Concepts related to basic plant parts and needs, nutrition, food production, recycling, agricultural technology and other areas come to life in these soilless growing environments. These studies may even lead to classroom business opportunities or fuel student career interests. Not the least of the benefits is the joy of students harvesting a crop of their own incredible edibles!
This guide features a synthesis of information from hydroponics experts and from people who have explored hydroponics with children in classrooms. It presents basic how-to information, suggestions for helping students discover concepts through investigations, plans for simple hydroponics setups, and stories from classrooms where students and teachers have investigated this growing technique.
Let the discoveries begin!