I am here a little late. Change Subject to Phal Keikis - was Air Layering. :-)
I regularly use keiki paste on some plants after my Phals are done blooming. If the plant appears tired or stressed or not 100 % up to snuff, I do not apply keiki paste. The paste is applied at the nodes on the stem(s). To facilitate, I cut the sheath covering the nodes gently with a scalpel and use tweezers to remove it - the sheath. I have seen Youtube videos of this lady ripping them off with her finger nails. Dont do that unless you want to trash the growth point bud. After you have done it a few times, you can look at the bud and have a feel for whether it will do something or not. Before hand, you can not determine if it will throw more blooms or make a keiki.
I have 12 phals. Of these, I applied keiki paste to about 1/2 over the past year. Of the 6, 3 threw out new blooms, two threw new blooms and a keiki and the others made only keikis. I also had one that threw a terminal bloom. That one on its own with no paste made 2 keikis - one on the stem and one basal. Likely the plant knew it was a goner and was trying to "survive".
You should not apply keiki paste until the plant has completely finished blooming! Also - you can only do so on stems that are green and healthy. If they are turning brown or otherwise do not look healthy, don't waste your time.
Right now I have 7 keikis - the oldest is nearly a year old and is big enough to remove from Mom. On one plant I have 3 keikis - one basal and one each on former flowering stems.
All of the plants that have keikis are some of my best looking and healthiest plants.
FWIW, I have never heard of air layering an orchid.
Keiki paste ranges in price from $7 to over $30. I have experience only using the product named Keiki Power Pro.
Once a Keiki has formed, I treat its base with Root Tech cloning gel (a common rooting hormone used for taking cuttings) which helps to create roots. It seems to help and my tests show that it seems to help about 50 % of the time. E.G. two keikis forming at the same time on one plant, one treated and one not. The one treated grew roots sooner and faster and the roots were larger.
As noted above, Phals can make a keiki with no human intervention. It apparently happens quite often after a Phal has made a "Terminal" bloom.
I have been playing around with keikis for over 2 years and have been growing Phals for 4 years. I also have one Cattalaya. This is all I have as my wife refuses to allow me to buy any more.
I think some of you folks failed cause you had the Phals outside. I grow mine year round in the kitchen. So their environment is basically almost the same year round except for light. They are exposed to some light from South window, mostly from West windows.
I have done a lot of air and ground layering and would not describe this as air layering. If a keiki does form, it makes leaves first. The leaves may be around and grow for several months (as much as 6 in some of my cases) before you see a root. I have one keiki that has 4 leaves, the largest nearly 5 inches. It has 4 roots, the longest being about 2 inches.
People who know a lot more about this than me suggest that you do not remove a keiki unless it has at least 3 roots at least 1 1/2 inches minimum. This is for stem based keikis. Basal keikis can be so intertwined and attached so close to Mom, that I simply do not attempt to remove them for fear of killing either or both Mom and the youngster.
In nature, it is my understanding that when the time is right, a stem based keiki simply falls from Mom as the stem dies back and it attaches itself to whatever Mom is attached to.
