The solution is injected into the trough by successive laser-cut apertures in a direction opposing that of the solution flow. This carries oxygen from the spray zone into the nutrient solution, aerating it and providing high oxygen concentrations at the root surface. This permits the roots to be immersed in a deep, large volume of nutrient solution, in troughs of any length. Aeration and delivery of spray varies according to the different designs of Ein geidi systems. The trough system uses a remote mechanical pump and piped spray system.
Roots also grow in the spray zone.
The spray is created by injecting nutrient solution, at relatively low water pressure through strategically placed nozzles. While there are no significant commercial EGS installations in Israel, other than those used for ornamental plants, commercial installations are in operation in Belgium and the USA, with tomatoes and cucumbers the major crops grown. It functions by drawing water up from the bottom centre of the container through a hollow, rotating impeller, driven by an electric motor. The drawn water is then thrown horizontally by centrifugal force into the air space above the water reservoir, creating a fine spray of water and, therefore, increasing the water surface area. Then, as the water droplets fall back into the agitated water, gas exchange takes place.