Mature plants generally need to be watered about once per week, smaller plants perhaps every 4-5 days during most of the year. In cooler temperatures plants may be left a little longer between waterings. Always water thoroughly, allowing water to drain well through the drainage holes in the bottom of the pot. In the home, an east, shaded south, or west window. Less light is needed during the winter months.
Needs vary greatly.
It is best to follow the plants natural requirements. Most oncidiums will do well in intermediate conditions that are usually found in most homes. When re-potting it is a good idea to under pot oncidiums rather then over pot. Most oncidiums are free flowering and will flower on each mature growth. In the home, an east, shaded south, or west window.