It's one of the general questions for the beginners who start to plant the orchid. The most common factors are as follows:

Not enough light

Generally speaking, if you are not providing sufficient artificial light, plants need to be close to a window, no more than 3' away at most. Plants see light from above, not sideways, and if you grow your plants too far from a window you will notice new growths becoming smaller and the leaves much narrower. They will not be able to store the energy they need to bloom.

Poor root system due to old potting medium or over watering

Poor root systems are caused by over-watering, or forgetting to repot when the medium is broken down. If this happens you will have to repot is as soon as possible in order to re-establish the root system.

Not enough temperature fluctuation

Temperatures should fluctuate below 65° Fahrenheit at night (preferable 60°) to above 65-75° during the day. Generally a 7-10° temperature fluctuation is needed to initiate decent flowering for most orchids.

Using a poor water source

Water should be clean. We always recommend using rain, distilled or reverse osmosis water. Soften water has too many minerals and will most likely slow down, damage, or kill root growth in orchids.