Depending on the season orchids may need to be watered every 4 to 7 days. The media they are grown in also plays a part.
Let your orchid reach a “point of dryness” but not completely bone dry.
One good method (growing phalaenopsis orchids – houseplants as well) is to thoroughly water your plant and gauge its weight, then when it is time to water gauge the weight again.
How much time has passed between waterings?
Whatever you do DO NOT allow your orchid to sit in water, make sure all water drains thoroughly!
Beware that orchids when in flower may require more water as the flowers do pull some moisture and energy. Orchids when not actively growing will require less water which is usually during the winter months.
In the the growing season during the spring and summer months orchids do require more water, but more water will not make up for a weak or poor root system. Roots need to be plump and alive.
Orchids with softer, thinner foliage in general require more water than varieties with “harder” leaves. Dendrobiums and Cattleyas for example need to dry out more than Phalaenopsis varieties before watering.
Orchids are not any more difficult to care for than other house plants. Phalaenopsis – the Moth Orchid – can hold flowers for 3 to 4 months.