Ebb and Flow - in Hydroponics

In Hydroponics

Ebb and Flow is a form of hydroponics that is known for its simplicity, reliability of operation and low initial investment cost. Pots are filled with an inert medium which does not function like soil or contribute nutrition to the plants but which anchors the roots and functions as a temporary reserve of water and solvent mineral nutrients. The hydroponic solution alternately floods the system and is allowed to ebb away.

Under this system a water-tight growing bed, containing either clean gravel or coarse sand as the rooting medium, is periodically flooded for a short period (5 to 10 minutes) with a nutrient solution pumped from a supply tank. By placing the nutrient solution supply tank below the growing bed, the nutrient solution can drain back by gravity. This hydroponic growing system is little used today other than for hobby-type systems. The method is inefficient in its use of water and plant nutrient reagents. Root disease occurrence and nutrient element insufficencies can occur with repeated use of the nutrient solution. Because it is a "closed” system, the re-circulated nutrient solution will require reconstitution, filtering, and sterilization. Within the growing period, the nutrient solution may require replacement. The rooting medium will require washing to remove root debris and accumulated precipitates as well as sterilization before reuse.