There is no "Holy Grail" for success with Orchids.
What works for one might not work for others.
Hydroponics does work for some plants and some growers.
Take a look, maybe experiment and you might be pleased with your results.
You can find information by searching the internet for:
"Hydroponics"; "Hydroculture" and "Semi-Hydroponics".
This is one link I have found very useful:
There is an article about Wally Thomas and his use of perlite here .
There is a copy of an article by Geoff Hands here.
Most Orchids cling to trees or rocks and have little more than air surrounding their roots. The advantages of the medium used in hydroponics is that it does not rot, break down and suffocate the roots. Be it Perlite; Clay Pellets or Lava Rock, there are air spaces around the roots.
These plants are in bloom now (February 2006).
The pots with holes in the side are semi-hydroponic as per First Rays ideas
(there should always be a reservoir of water in the bottom of the pot).
The green and blue pots are kept in a flood-table in 1 inch of water and flooded regularly(???) to a depth of 3 inches for 10 minutes at a time. (I also water from the top.) Geoff Hands article suggests flooding every 4 days in winter, every other day in spring and fall and 2 to 4 times per day in summer.
The mix is typically 50/50 perlite/clay pellets or sponge-rock/clay pellets with pea gravel on top.
Click on the thumbnail pictures to see an enlarged view.
Blc.(Mem. Boon Klong x Ewart McDonald)
Oncidiums are rumoured to do well.
This Sharry Baby just finished 3 spikes (3 feet long).
This Aerides was part of the first Philippines order and it limped along for some time in a wood basket. Since putting it in Semi-hydroponics it has now established itself and you can see the new roots and leaves.
Here is a corner of the flow-table. (2' by 8' pressboard with 1" by 3.5" sides lined with pond-liner)