In summer I give them a good watering with Orchid food when the pot is light or the wood chopstick comes up clean but in winter it is more difficult to gauge due to so many different factors; sunlight, temperature, what type pot they are planted into - some pots dry out quicker than others.
My orchids like the South window in the summer when the sun is high and not shining directly on them. In winter they prefer the north side and do not need as much watering.
