Is it organic?
This is a question were were asked a lot at the old hydroponicum and continues to be asked at The Achiltibuie Garden.
The organic / hydroponics question is a fascinating area. The bottom line is that the nutrients used for hydroponics are manufactured from inorganic chemicals, aiming to mimic what the plants would take out of the soil. In conventional growing, plants live on inorganic chemicals which they obtain from the processes that go on in the soil: they dissolve salts from the rock/mineral content of the soil and from the breakdown of organic matter by bacteria and fungi. These are all inorganic substances and can be replicated in a solution which gives the plants the same nutrients which would be obtained from soil.
At present there is no organic standard for hydroponic growing. Certain aspects of agriculture which are assessed when awarding organic status, like maintaining soil fertility or controlling weeds in an approved manner, do not apply to hydroponics. Hydroponic growers do not maintain the soil - they leave it alone, and they do not control weeds because there are none!