Phalaenopsis in water culture

[orchidsamore]

The reason you do not rot the roots in water is that decay is a living organism and requires moisture (water) and air to grow. There is no usable oxygen in water so decay does not grow.

Undergrounder is not correct when he describes water as 1/3 oxygen (actually 80% oxygen by weight weight of H is 1 and O is 8) but the oxygen is bound to the hydrogen molecules and is not usable to anything as oxygen.

There is dissolved oxygen O2 in water but it is not in a form that can be used by the decaying organisms, similar to the way we can not use the oxygen to survive while fish can.