Question
Hi,
I have 3 phalaenopsis orchids.  Two are in a bark/charcoal orchid potting mix, and the third is in peat moss, with some styrofoam peanuts at the bottom. All three were blooming when I got them, and lost their blooms shortly after coming home (some I actually got on discount because they were 'damaged', they also came home in the middle of the winter and may have been shocked by the cold.)

The two in the bark mixture are growing very slowly, both have put out one new leaf, but nothing else.  One was also infested with ants lately, and I had to repot it.  The leaves of this one are starting to shrivel.

The third, in the peat moss mixture, is doing much better.  It has put out three new leaves in rapid succession, and a fourth leaf that is very small (about 2 inches) and shaped like a heart, which just stands up vertical.

My question is: What is it about the peat moss mixture that is encouraging much better growth than the bark mixture?  There must be something I can do with the two in bark to help encourage their growth. Perhaps it is something with the watering?
Thanks,
Ramona

Answer
Hi Ramona,

Cold shock can set back phalaenopsis orchids which do not like temperatures below 50F even for a short time.  As long as it wasn't for more than a few minutes, they should recover.  

Why the two in the bark mix recovery is so slow with only one new leaf could be due to the bark mix having broken down.  To verify this, after watering them try smelling the potting mix to see if there is a sour odor, if there is that would mean the bark should be replaced.  Get some orchid potting media and you're ready to repot.  Unpot them and check the roots for any that may be soft and mushy, remove any that are as they are dead.  Limp and shriveling leaves is usually a sign that there may be rotten roots.    Clean off as much of the old bark as you can, place about an inch of fresh mix in the pot then lower the roots and plant into it so the bottom leaf is just below the pot rim.  While keeping the plant near the center of the pot, add mix around it and between the roots.  Once full, gently compress the mix and add more as needed to fill the pot.  

The phalaenopsis in the peat mix could be growing better because the phal had been repotted just prior to your having bought it.  Peat mixes are fine but they tend to break down sooner than bark mixes.  Orchids in peat mixes should be repotted into fresh mix annually because peat tends to break down within 6 to 10 months.  

Peat moss holds and retains water for longer periods than bark, that may be why the one in the peat mix is doing so much better.  If you water infrequently, peat might be a good choice but if you water more often the bark might be better because it dries quicker.  The choice is yours.  

Lastly, if you really like what you see with the peat mix, you might get more orchid mix containing peat moss to repot the other two.  

Hope this helped with your questions.  If you have other questions or would like more information regarding the above, write back and I'll try to help with them.  

Jim Kawasaki
San Jose, Ca.