Question
QUESTION: My husband gives me an orchid every Valentine's day as well as one for our anniversary every year.  We live in Colorado, along the Front Range of the Rocky Mountains.  The climate here is generally very sunny (300  days per year) and pretty dry.  During the winter, I have a humidifier bringing the air to 50 with the heater.  So far, I've been having quite a bit of success with the following method: water once weekly by soaking in tepid water for 1-1 1/2 hours and place in east facing window on sunny days when it's warm enough.

I'm concerned, however, about my brand new Brassidium; the tag reads "BRSDM> Longlen 'Bill Switzer' AM/AOS (Fragrant spider flowers)".  I've noticed some black spots that do not appear to be any kind of fungus (and fungus isn't common in  a climate this dry).  After a while, some of the leaves began to yellow.  I've taken several photos of the plant, but am not sure where to upload them for someone to look at.  Any advice as to what might be causing the spots and yellowing, as well as any hints for care of this plant would be met with great appreciation.

ANSWER: Sheralee, my first concern would be at the root level.  If the plant has not been repotted in the past year, I would proceed to repot it in fresh orchid potting mix. As part of that process you should examine the roots for any that are mushy or stringy.  Healthy orchid roots are firm.  Remove any roots that are not healthy before repotting.  You don't need to soak the potting mix for as long as you do and, if the potting mix, is not in good condition it could stay overly wet at the root level for too long a period.  The potting mix needs an opportunity to dry out between waterings and that would be impaired if it is degraded. The room humidity can be quite low, but conditions in the potting mix can remain quite damp.  Your procedure may work well on plants with fresh potting mix because relatively fresh orchid bark is water repellant.  As that potting mix ages, it becomes more and water absorbant.  It may feel dry on the surface after a while, but the mix at the root level may still be quite wet or damp.

If there is no root problem, then I would look to possible sunburn.  If your plant gets some direct sunshine, that sunshine may be focused for a brief time, by a window or other focusing source on a small portion of a leaf or leaves causing sunburn.  Excess sun could also bleach out the chlorophyll on some parts of the plant causing the leavews to take on a yellowish or light green color. You can check out each or both of these possible causes and come to your own conclusions and make the necessary adjustments.  Remember that the sun effects can vary with season as the sun's angle is constantly changing.

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QUESTION: Thanks so much for such a quick and helpful response.  Although I only just received this plant for Valentine's Day this year (so I've had it just over a month now) the pot is plastic and the bulbs (?) are mostly large and pretty packed in there.  How crowded ought orchids to be?  I notice that many plants seem pretty jammed up.  Is this a condition they prefer, or should one try to give them more room on a regular basis?  (I guess what I'm asking is whether repotting is dictated by implied condition of potting material or the crowding in the pot - or both.)

Many Thanks!

Answer
Sheralee, the short answer is that most types of orchids prefer to be crowded. However, both crowded roots and a tight pot are a factor in the decision to repot.  Repotting in response to a broken down potting mix is, by far, the most important reason for repotting.  A potting mix that retains too much moisture prevents air movement through the potting mix and because orchids, in their native environment, usually have their roots exposed to the air they require an open enough potting mix to allow good drainage of water and movement of air. In cultivation, we try to mimic that by potting them in a manner that prevents the roots from drying out too much while allowing air movement at the root level-- it is a balancing act. Once roots have filled a pot, there is a good chance that the potting mix has deteriorated, allowing more room for roots.  I have seen plants that have totally exhausted the potting mix and the pot contains all roots.  Because roots have a covering called velamin which absorbs and holds moisture, orchid plants can survive with little or no potting mix (I know one grower who repotted his plant in glass chards from a broken patio door). While orchid plants can survive without potting mix, to thrive they do need a small amount of food which roots alone can't provide.

Most growers recommend repotting every one to two years.  In repotting Brassidiums (BRSDM), you need to check the roots and remove any that are in poor conditions (eg the velamin covering has broken down) and remove those before repotting.  If the roots are in generally good condition you should choose a pot that is 1-2 inches in diameter larger than the one it had been in.  That will provide enough room for new growth.  Repot only when new growth is emerging at the base of the plant-- or in an emergency.  I hope that helps.  If anything I have written needs clarification, please don't hesitate to let me know.