Question
I purchased an orchid three weeks ago, it had about 8 flowers.  It was moist when I purchased it so a week later I watered it, letting the water drain.  Now two blossoms drooped and fell off and I'm noticing brown splotches on the other flowers.  I also noticed one yellow leaf which just fell off.  This orchid has very large leaves.
 Wondering what to do.  I purchased this at a local hardware/florist.  
thanks

Answer
Jon, while I recommeend buying the plants while they are in flower, there should also be unopened buds.  The reason for this is that usually there is no way of knowing how long the plant has been in flower.  Your plant likely was near the end of its flowering period and, with no new buds to open, the old flowers are showing signs of aging and will fall soon.  if you cut off the green flower spike just above the second or third joint (ie node), your plant might send out a branch from the flower spike from the node just below your cut.  Another option is to check the end of the flower spike to see if you notice any tiny terminal buds.  If so, the green spike might elongate and reflower from the end of the old flower spike.  Not all phalaenopsis flower spikes remain green.  If yours turns brown, it will do so because it is genetically programmed to do so. You have not mentioned what medium the plant came in, moss or orchid bark mix?

Leaf yellowing can be due to root rot. It is always a good idea to repot your plant after each flowering. Hobby bags of orchid mix can be bought usually where these orchids are sold (eg. Lowes,Home Depot, etc.)  Choose a fir-bark based orchid potting mix. If you repot,the mix needs to be soaked overnite. Be sure to remove any of the old roots that are mushy or stringy and these are dead (healthy roots are firm). Repot in a plastic pot with lots of drainage holes--size depends on the roots.