Oncidium Orchids. Sometimes called dancing lady orchids, oncidiums offer lots of colorful smallish flowers in clusters of 50 or more. They commonly appear in shades of yellow, purple, red, pink, and white, often with flamboyant, contrasting markings. How to Grow Them: Oncidium selections do best in medium to bright light. Water them weekly or every other week and feed them monthly in spring and summer with an orchid fertilizer. They do best in temperatures from 50 to 75F.