Passive hydroponic systems
Passive hydroponic systems are systems that are primarily intended for use with soil or coco. The systems do not work with clay granules because clay granules do not have good enough transport properties and must be sprinkled with nutrient solution from above.
How it works
Passive hydroponic systems are systems that work by gravity and/or capillary action.
Gravity: the water reservoir is located above the planters and is transported to the roots through pipes.
Capillary action: the nutrient solution is located below the roots is transported upwards by suction force, like a cotton wick.
A constant water level of the nutrient solution is achieved by water valves. These function with a float, similar to a toilet flush.