How to Grow: Tolumnia Orchid Care

Updated: Feb 5


General Information


The group of orchids now called Tolumnia were at one time called Oncidium section Variegata or commonly referred to as "equitant oncidiums". The foliage seldom exceeds 6 to 8 inches in height, and a 4-inch pot can house a "specimen" plant. The leaves are arranged in pairs overlapping or straddling one another at the base, accounting for the popular term "Equitant". Flowers are produced primarily in the spring on 12- to 18-inch inflorescences that are often branched on older plants. Some types have much shorter, bouquet-like displays.

The key to growing Tolumnias is understanding their natural habitat. The species are endemic to the Central America and Caribbean Island Basin with many confined to a single island. Most of the species involved in modern hybrids are found in intermediate to warm conditions growing on twigs where they are exposed to bright light and air movement. Moisture is provided by high humidity and by daily rain showers. Due to constant air movement by the trade winds, plants never remain wet for long.


These plants can often bloom more than once a year. Larger specimen plants or large collections of Equitants can provide some blooms most of the year round. Today's hybrids offer an astounding array of colors and patterns not seen in the species. Their petite size and ability to adapt to a fairly wide range of conditions make them suitable for growing spaces under lights or on windowsills.

Light Requirements


Tolumnia orchid loves bright sunlight and is able to tolerate direct morning and evening sun, however, in the hot summer noon especially in the windows of southern orientation, the orchid should be protected from direct sunlight. They do well growing in an east window receiving sunlight from early in the morning until 11:00 or 11:30 AM. Put behind a curtain for example, on a table near a window or in the shade of other plants, otherwise the plant can get a sunburn. The intensity of illumination can be judged by the state of the leaves of the orchid, if their color becomes lighter, with yellowness or whiteness, then in this case too intense illumination takes place. In the absence of sunlight, on the contrary, the leaves of the orchid have a darker green color.


Temperature Requirements


This kind of orchid refers to a moderately warm temperature regime, and it is recommended to keep the orchids under the following conditions throughout the year:


Day temperature at 20-30° C and Night temperature at 14-23° C . To successfully grow Tolumnia at home, it is necessary that the night temperature of the content is always 5 ° C lower than the daytime temperature. They will endure occasional deviations, but extremes lower than 14° C and higher than 32° C for any length of time should be avoided.


Water Requirements


This is the most crucial aspect to success with tolumnias. There is no hard and fast rule for how often to water. Watering directly depends on the temperature of the content, the higher it is, the more often and abundant it is necessary to water. Plants growing on blocks should be watered daily in the morning, so that by evening the roots of the orchids could dry out relatively well. When watering orchids in pots, it is necessary to remember that excess water during watering should flow freely out of the pot, as the stagnation of water both inside the pot and in its pallet can very quickly lead to rotting of the roots and the lower part of the plant. The substrate between waterings should dry well.


On hot summer days, daily spraying of the outer part of the plant is recommended, which will additionally increase the humidity of the air around the orchid and help it better survive the heat. Water that collects in the overlapping leaf bases can reach "cooking" temperatures and severely damage plant tissue, especially the tender young growths.


Humidity Requirements


For normal growth and development the relative humidity level of 45-70% will be enough. For plants planted in blocks, a higher air humidity is desired than for a pot culture. Too dry air negatively affects the development of the plant, its growth is inhibited, and the roots of the orchids begin to dry out. The higher temperature rises, the higher must be the humidity of the air, and the higher the humidity of the air, the more often and longer it is necessary to ventilate the room where the orchids are kept, otherwise there is a high probability of decay and appearance on the leaves of various fungal diseases.