Question
HI Jim,
I fear I'm becomming a serial Orchid killer please Help.....
I have quite a few phalanopsis plants that have developed floppy, creased
dark green leaves and i don't know what I'm doing wrong.
I've tried creating a mini greenhouse environment for them enclosed behind
plastic sheeting with a steady temprature of 15degrees, full winter sun (it's
winter here in New Zealand) but not too close to the window and sitting on
top of trays of rocks with a little water below rock level to add to the
moisture. The plants are fairly mature about three years old and they were
each given about an egg cup of water before going into the greenhouse.
I left them like this for two weeks and when I returned two of the plants had
grown ok, but the lower leaves of about 5 of the other plants had turned
yellow and fallen off and the remaining 10 plants had developed floppy
creased dark green leaves (some of the floppy ones were like this before the
mini green house experiment) but they seem worse now. there seemed to be
no pattern to indicate the cause, with the healthy plants in opposite corners
and the ones with dead and falling off leaves scattered among the others. I
can't see any signs of bugs, mould or anything else obvious but would love
your advice as to how I may be able to get them to grow strong leaves once
more. Many Thanks Coral


Answer
Hi Coral,

From the description of what is happening to your phalaenopsis orchids, there may be more than one thing causing the leaf problems.  

One is the constant 15C as phals enjoy slight temperature variation between day/night.  Is it possible to increase the day temperature upwards close to 25C?  

Another possible cause is the mini greenhouse if there is no air movement within it.  Water that collects on the leaves can be a prime breeding environment for fungus and bacteria, especially at night.  Air movement would help the water to evaporate off the leaves.  

Floppy and wrinkled leaves could be an indication that some or all of the roots have rotted within the pot.  The only way to be certain of this is to unpot them and check the roots, if they are soft and mushy they are rotten as live roots will be firm when squeezed.  

One thing that might be contributing to the root problem is the potting media.  If the potting media has broken down, it will tend to remain wet much longer.  To check this, try smelling the media and if there is a sour odor present that would indicate the media should be replaced with fresh media.  Winter is not the best time to repot phals but if they are in pretty bad condition, it can be done as long as they are kept in a warm place for about a month after repotting.  

Lastly, the major cause for killing phalaenopsis and orther orchids is water.  Most orchids should only be watered when the potting media becomes barely moist.  Unless there is some light air movement present, drying time can vary from 5 to 15 days and longer depending upon season, light exposure, humidity, etc.  

Lastly # 2.  Leave the floppy wrinkled leaves on the plants as they are still capable of helping the phals recovery.

Although I've never been to New Zealand, I've met several Kiwi's over the years.  One that recently passed away was Ray Dix, a really great person who died too soon.  My mother and father while on vacation there spent several days at a farmers house 15 years ago and talked about it for years after.