The care that it needs will be dependent on what kind of Orchid it is.
The most common one sold at many stores these days, including at the Home Depot where I work, in the Garden Department, is Phalaenopsis, and they are not potted correctly for continued life, unfortunately.
In their natural habitat, most Orchids don't grow in the ground like "normal" plants, they grow in various combinations of debris that collects in the crotches of trees in the jungle. Depending on what part of the country you live in, Home Depots will have proper Orchid potting mixes, and proper receptacles in which to plant them. The key is that Orchids require both good drainage and *ventilation* at their roots.
I live in West Virginia, so the only type of Orchid pot we sell in my store is a clay one, with vertical slots on the sides to enable that ventilation. We also sell a pretty good Phalaenopsis potting mix that has repotting instructions on the bag. I just sent away to Home Depot dot com for little cedar baskets to transplant my Cattleyas into. You can find a lot of fairly good care sheets online, depending on the variety. Orchids' needs aren't too elaborate, but they ARE quite specific.
I would be very interested in what type yours is, and hopefully we can get it turned around for you
Carol
