|My phalaenopsis orchid grows new tubers but won't grow a stem or a bloom.|
|Orchids are an incredibly independent lot! But they are lovers of humidity and I find they won't flower without it. Have you tried setting the pot on top of pebbles with a shallow layer of water? As the water evaporates, it increases humidity around the plants. Don't let the pot/roots sit in the water, but just above it. Light daily misting can also help.
Also, since orchids are generally planted in something like bark, they need to be fertilized regularly for nutrients. My friend who has a greenhouse full of orchids recommends fertilizing with a balanced fertilizer each time you water, but use only 1/4 of the amount of fertilizer recommended on the container. Try to be patient. If the plant looks healthy, it will probably bloom again in time! Also, phalenopsis can bloom for a couple of months or more once they start! Good luck.