Question
HI,
I've bought 3 orchids (pali... I think) recently.  One large and 2 mini. With the large one, all flowers fell off and the lowest leaf has turned yellow.  I haven't cut the stem down...should I? The minis were doing well but the lowest leaf of one has turned yellow and fell off yet there are still flowers and even buds that are not open, some flowers fell off recently but not all.  The other mini has 2 spikes. One has lost all its flowers, the other spike still has flowers but lost some.  The leaves (so far) are green.  The two with yellow leaves are on one table the other is on another table nearby.  They both get the same amount of light from the window but not direct.  I water the bark planted ones once a week putting them in water for 10 mins. then letting them drain, the soil? one gets water as needed.  Sorry for such a long explanation, hope you will help, I love these plants they are so pretty when flowering.  Thanks, E.

Answer
Elaine, it is not unusual for the oldest (lowest leaf) to fall off.  Nor is it unusual for flowers to fall from recently purchased plants as they may have been in flower for some time and have naturally reached the end of their flowering period.  The thing to be most concerned about is to repot the plants once they have finished flowering.  Often times, the potting mix on freshly purchased plants has deteriorated.  Since deteriorated potting mix holds water longer and keeps the roots wet longer than should be the case, I recommend letting the potting mix thoroughly dry out between waterings until you can repot the plants.  Hopefully, all of your plants are phalaenopsis orchids (ie phals) as my advice is keyed to those.

To repot, purchase a bag of orchid potting mix. (You can find this at either a Home Depot or Lowes garden center). I recommend the coarser mix which can then be soaked prior to use. Fresh orchid potting mix consists largely of fir bark which repels water when dry.  Soaking it reduces the water repellency of the potting mix which is better for the roots.  This fresh orchid potting mix allows for better drainage when watering and allows more air to flow to the roots.  An annual repotting following flowering is recommended.  Use pots that have lots of drainage holes (preferably plastic).  When you remove the plant from its pot for repotting, rinse off the roots thoroughly and remove any roots that are mushy.  Healthy roots are firm.  Mushy roots are a sign of rot and the result of potting mix that remains too wet and permits little air movement to the roots. Insert the healthy roots into the pot and add the wet, fresh potting mix to the pot until the roots are covered. Do this where the water can drain freely. Water regularly once per week allowing the water to drain away prior to returning the plant to its growing area. An east window where the plants can get some morning sunshine is the best growing area. Hope this is helpful.  It may raise further questions so ask away as the need requires.