Even though orchids are tropical plants, most do not like to have moist soil at all times. Different varieties of orchids have different watering needs, so read the label that accompanies your plant to find out how much water it needs. In general, water a potted orchid in the morning and at the base of the plant--not from overhead. Do not let the soil get soggy, and dump out any water that collects in the drainage tray. During hot and dry months, an orchid needs more water than during other times of the year.
Maintain moist soil conditions all year long for orchids soil such as Cymbidium, Odontoglossum and Miltonia orchids. When the soil feels dry to the touch, water the orchid with about an inch of water.
Keep the soil evenly moist from spring until fall. During the winter when the orchids are not actively growing, let the soil dry out to about 2 inches deep before watering them again with about 2 inches of water. Examples of orchids that prefer this kind of watering are Brassia, Cattleya and Oncidium.
Allow the soil to dry out all year long between waterings for some orchids, such as Vanda, Phalaenopsis and Ascocenda. Stick your finger into the soil and when it is dry to the tip, water these kinds of orchids until the water drains out the bottom--but dump it out.