Backyard Aquaponics
A place to discuss aquaponics

I was surfing the web and found several commercial systems that grow lettuce by floating them in growbeds. My question is (please keep in mind I am a newbie) how do the roots get enough oxygen if constantly floating in water? Don't they have problems with rot and the such? I know I am missing something, someone help out the clueless one here?

Gregg

A fairly rapid turnover of the water back to the fish tank (where it is oxygenated by waterfall, airstone or some other method) is the key. Some floating raft systems will also contain airstones in the beds.

Basically the same theory/application that underpins hydroponics nft techniques as well .... high oxygenation and flow....

As the nutrient water level is lower in nft applications the flow rate can also be lower than DWC systems.... obviously with a lower level the oxygenating roots are exposed to the air, whereas in DWC systems they must absorb all their oxygen requirements from the water itself.