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Tolumnia (Equitant Oncidium) Culture

Tolu. Little Bird Reef 'Sun Bird', HCC/AOS; photo copyright AOS

Tolu. Little Bird Reef
'Sun Bird', HCC/AOS

Cultivating Tolumnias boils down to what works for the grower. Not all growing areas are created equal and there is some degree of trial and error that must be endured. Once the right combination of factors is found, these little gems will work hard to please you.

There are two basic requirements that must be observed whether Tolumnias are grown outdoors, in a greenhouse, on a windowsill or under lights: air movement must be good, and the plants must not be overwatered. In the wild, these plants grow on twigs with their roots freely rambling to catch dew and rainfall then quickly dry in the passing breezes.

Temperature should ideally range from a low near 60F to a high of 80-85F. They will endure occasional deviations, but extremes lower than 50F and higher than 90F for any length of time should be avoided.

Light should be bright but diffused. Outdoors, a spot in bright dappled shade is best. Indoors, an east or south exposure is best, with care to protect the plants from direct sun during the heat of the day. Under fairly humid conditions, mounting on cork slabs or tree-fern plaques is the best approach to "potting." If constant humidity above 50 percent is hard to maintain, actual potting in a coarse fast-draining mix will retain a little moisture about the roots long enough avoid desiccation.

Watering should be done as often as the plants dry out. Mounted plants benefit from daily misting, and the risk of overwatering is diminished. Those in pots should be monitored carefully at first to determine watering intervals. Overwatering encourages root rot.

Fertilizing can be done at regular intervals with a dilute (1/4- to 1/2-strength) balanced fertilizer.

The most frequent pests are scale and mealybugs. These are best avoided by frequent observation of the plants and immediate treatment if found. One of the insecticidal soaps will give adequate control on occasional flare-ups. Diseases are not frequent problems because of the preferred dry-side growing conditions.

Hint: Do not cut the inflorescence after initial flowering. It will often branch and continue with another flush of blooms.

To read more on Tolumnia culture click here.

To read the article Tolumnia Golden Sunset - A Growing Legacy click here.


Anita Aldrich is well known for her Tolumnia hybrids. She is a former vice president of the American Orchid Society, former chair of the Committee on Awards (now the Judging Committee) and former chair of the Society's Conservation Committee. She is an accredited AOS judge and owner of Sundance Orchids. 817 89th Street, Galveston, Texas 77554 (e-mail aaldrich@wt.net).