Question
I've been a grower of carnivorous plants for 3 1/2 years now, and finally decided to round out my collection by buying an orchid plant for my window. The only store in town that carried orchids was a Lowe's, and Dendrobiums were 75% off. I picked up a healthy looking one and brought it home- the plant is now receiving light from an unobstructed south window, and is watered as the top of the sphagnum in which it was planted becomes dry. I use orchid fertilizer (20-14-13) at 1 tsp per gallon every watering. I'm very new to growing orchids, and although the plant seems fine for the moment, I want to make sure I'm doing everything right. Thank you for your time!

Answer
Corey, I'm pleased that Lowes sells orchid plants at a reduced price when they go out of flower.  Dendrobiums are a diverse group of orchids. You probably have an evergreen type that retains its leaves during the rest period.  I would go easy on the watering during the period when there is no new growth coming.  I also would not feed the plant until new growth appears. Sphagnum is a tricky growth medium for any orchid plant.  The problem is that it can compact over time restricting the flow of air to the roots. This problem is worsened if sphagnum is the only potting mix because it is difficult to maintain an even moisture throughout the root zone. The most common reason for root loss in dendrobiums is a wet root zone during the rest period as the plant is not growing and cannot use the moisture.  That root rot can then spread to the canes causing loss of the plant.  Provide just enough moisture/humidity during the rest period to keep the canes firm.  When you see new growth, I recommend you repot your plant in a standard orchid potting mix after you have thoroughly soaked it.  It's okay to use a top dressing of long fiber sphagnum which tends to resist compaction.  I recommend a clay pot with lots of drainage holes. Dendrobiums like to be tightly potted so use a pot that it can barely fit into. After repotting, when the plant is in active growth, it will benefit from frequent watering and feeding providing there is good drainage.  Avoid allowing the pot to stand in water.

Your orchid food is heavy on nitrogen which will be fine when the plant enters active growth.  When the new growth matures, switch to a fertilizer high in phosphorous (ie higher middle number).  It is not unusual for dendrobiums to remain at rest for several months so be patient.  A south window is fine this time of the year.  As summer approaches, your south window will not be as sunny and you may want to consider summering the plant out when temperatures do not get below 50 degrees.