Noun the process of growing plants in sand, gravel or liquid, with added nutrients but without soil. There's no mention of soil anywhere, and that's all the proof you need that plants can grow without it. What they do need is water and nutrients, both easily obtained from the soil. But if they can get these things somewhere else, say, by standing with their roots in a nutrient-rich solution, they can completely dispense with the soil.
That's the basic principle behind hydroponics. In theory, the word hydroponics means growing plants in water (from two Greek words that mean water and work), but because you can grow plants without standing them in water, most people define the word as growing plants without using land. Hydroponics means “working water” (hydro means water and ponos means work). Many different civilizations have used hydroponic cultivation techniques throughout history.
One of the potential applications of hydroponics that drove research was the cultivation of fresh produce in non-arable areas of the world and areas with little or no soil. In 1940, Gericke, whose work is considered to be the basis of all forms of hydroponics, published the book Complete Guide to Soilless Gardening. The white surface of hydroponic containers like these helps to reflect light evenly on plant leaves, improving growth. Although the benefits of hydroponics have sometimes been questioned, there seem to be many advantages to cultivating without land.
Because hydroponics requires much less water and nutrients to grow produce, it may be possible in the future for people in harsh environments with little accessible water to grow their own food. Commercial hydroponic production of large plants such as tomatoes, cucumbers and peppers uses one form or another of waste hydroponics. One of my friends at Outside, Mary Turner, told me that she was being sent an elaborate hydroponic platform made by a Los Angeles-based company called Lettuce Grow. For all techniques, most hydroponic reservoirs are now constructed of plastic, but other materials have been used, such as concrete, glass, metal, vegetable solids and wood.
Nutrients used in hydroponic systems can come from many different sources, including fish droppings, duck manure, purchased chemical fertilizers, or artificial nutrient solutions. NASA research has shown that aeroponically grown plants have an 80% increase in biomass dry weight (essential minerals) compared to hydroponically grown plants. The main advantage of hydroponics is the saving of reduced labor costs, since it is usually carried out in enclosed areas and irrigation and fertilization are carried out mechanically. The compounds can be added in both organic and conventional hydroponic systems to improve nutrient acquisition and absorption by the plant.
Alexander said hydroponics (saving water by growing plants without land) is just one piece of the puzzle for future agriculture. Hydroponics is a type of horticulture and a subset of hydroponics that involves the cultivation of plants, usually crops, without soil, by using water-based mineral nutrient solutions in aqueous solvents. As NASA considered the practicalities of locating a society on another planet or on Earth's moon, hydroponics fit easily into its sustainability plans. Within the center of each rotating hydroponic garden can be a high-intensity growth light, designed to simulate sunlight, often with the aid of a mechanized timer.