Simply put, aeroponics is a method of growing plants in a soilless environment with very little water. Basically, it's growing without earth. Despite this leap in advancement, aeroponics actually had a fairly slow start. Techniques for growing plants without soil were first developed in the 1920s by botanists who used primitive aeroponics to study plant root structure [source: Barak, et al]. This absence of soil made study much easier: In aeroponics, plants' roots dangle in midair, with only the plants' stems held in place. However, the leap in logic that led to growing plants in this way for recreation rather than academic study didn't occur until the 1970s. Hydroponics, a similar technology where plants' roots are grown in nutrient-rich water rather than soil, emerged and overtook aeroponic development.Hydroponics (growing roots in a nutrient rich, water-based medium instead of soil) came into popular use in the West in the 1970s. Research and use of aeroponic systems continued behind the scenes, however, and the technique made its big public debut when "The Land" pavilion at Disney's Epcot Center opened in 1982. It would take the interest of NASA to push aeroponics further into the limelight. In the 1990s, study and refinement of these techniques took off after NASA funded a project by a small aeroponics operation. NASA's involvement would give the growing aeroponics movement a decidedly futuristic image.Imagine a board with holes drilled equidistantly apart and plugged with a stabilizer like foam rubber. After plants germinate from seed in a soilless medium like Rockwool, (a fibrous material woven from strands of lava) they're transplanted to the board. As the plant grows, the upper parts of the plant (the crown) grow above the board, while the roots are left to dangle below.Beneath the board is an enclosed area known as the root chamber. This area's purpose is twofold: It protects the roots from light and it holds the nutrient/water solution that feeds them. A sump pump pushes the solution through a pipe and out of a series of nozzles that atomize the solution and spray a fine fog directly onto the roots. In an enclosed system, whatever doesn't get absorbed by the roots falls back down into the solution chamber and gets cycled through again. The pump is set to an automatic timer and delivers this high-powered nutrient solution at regular intervals.A-frame aeroponic systems are also in wide use. Instead of horizontal boards, A-frame systems use tall cones made of PVC frames and enclosed with chicken wire and plastic. The interior serves as the root chamber. The plants' roots hang at a downward angle inside the cone, while the plants grow upward through the plastic on the side. (Think of a Chia Pet teepee.) A-frame systems have a decided advantage over horizontal systems in that they require less square footage for the same plant density, since the systems are arranged upward instead of outward.This kind of thinking reflects the basic premise behind aeroponics using the minimum amount of input to gain the maximum output. The fact that it lacks soil is another important aspect. Soil provides plants with stability, warmth, and an easy way to distribute nutrients and water. But soil is also stingy, especially when it comes to allowing plants oxygen.