Ebb and flow hydroponics

Root disease occurrence and nutrient element insufficiency can occur without repeated use of the solution without proper oxygenation of the containers that are flooded.

[1] The fundamental principle of hydroponics relies on fertilized and aerated water which provides both nutrition and oxygen to a plant's root zone.

Active aeration of the fertilizer solution is common, since root systems themselves remove oxygen, creating conditions which also can promote pathogenic bacteria and water-borne molds.

Instead it relies on characteristics of root function to provide passive oxygenation at a high level which tends to suppress pathogen growth.

The time it takes to flood the roots is not a critical parameter, which means that pumps are often moderate in capacity and can be small for systems sustaining indoor plants.

Gravity acts as drain pump in some systems, and aeration is accomplished through thin-filming and positive displacement of air as it is forced out of the root zone by water.

The high oxygen content of water filmed in this way suppresses most harmful lifeforms, keeping the root zones disease free.

Larger containers require transferring the media to a suitable surface after sterilization to permit removal of leftover plant material.

Commercial crops harvested at one time are somewhat immune to concerns related to that aspect of the system, but in the event of pathogenic invasion the problem can quickly spread, as all the roots share the same flood source.

In tables where plants are larger than optimal for the system, this can create the need for modifications such as screens or beds of medium-sized gravel to prevent standing water.

The temporary rise in the oxygen level is only minimally damaging to roots, while eradicating the water-borne mold can significantly increase yield or even save a crop's viability.