Tolumnia

Light should be bright, diffused light somewhere between that for phalaenopsis and cattleyas. Plants growing well but reluctant to bloom usually need more light, but do so gradually to prevent burning, especially when moving plants outdoors for the winter

• In a greenhouse they need about 64,500 lumens (6,000 foot-candles) and above, depending on the plants.  
• In the home, east, south or west windows where they will get at least 2 hours to a full day’s worth of sun are ideal. 

Temperature tolerance for this group is generally considered cool to hot: 55F to 60 F (13C–16C) the lowest at night, and 70F to 100F (21C-38C) during the day.  They are happy indoors at room temperature, and you can be successful with Tolumnia even if the temperature does not swing that much from day to night.  A good general rule: high temperatures are tolerated, but only if the plant cools down at night and water is increased.

When thinking about Tolumnia, you must keep in mind that because they grow on the tops of the trees, they like to have quick wet/dry cycles. Tolumnia like to go dry in between waterings but like to be immediately watered when their media hits dryness.  Use lukewarm water!  Water temperature below 50F (10C) may injure plants, as will hard water or water softened by the addition of salts.   If not enough water is given, or there is too much time between waterings, the plants will exhibit “accordion” growth or will start to get wrinkly.  Avoid wetting foliage, as they are rather susceptible to various infections.  Again, the frequency of watering will depend on how fast it takes for the media to dry in your conditions.

• In a greenhouse – water daily; twice a day if the temperatures are above 85F (29C) regardless of whether or not it is potted or mounted.
• Indoors – these plants should be grown potted and watered every day to every other day.  Ideally, they should be taken to the shower or sink and be watered, drip dry, then be placed back.  The frequency will depend on how fast it takes for the media to dry in your conditions.

Humidity is important – and should be kept between 50 to 70%.  Be sure to incorporate airflow if conditions are soggy, or the humidity is >75%.

Fertilize regularly to produce strong growth.  Use ¼ strength to regular strength of a high nitrogen formulation (such as 30-10-10) while plants are in active growth, slowly tapering off as pseudobulbs forms. A bloom-booster formulation (such as 10-30-20) should be used as flower spikes are forming. Do not fertilize during the winter. Also, depending upon your water quality, flush the plants with plain water to remove built-up salts in between fertilizer applications.

Potting should be timed to coincide with the initiation of new growth. Usually this occurs in the spring, but these plants tend to grow year-round, so anytime is the right time so long as they are not in spike. New roots will be produced quickly at the time of new growth, and plants will experience minimal setback. These plants have vigorous root systems and require an evenly moist, but breathable, potting medium during the growing season. Even though they can be mounted, many greenhouse growers pot their Tolumnia to ensure that they don’t dry out.  

• In greenhouses, plant in anything from 100% treefern fiber to 100% coarse-grade orchid bark mix. In very humid greenhouses, these can be grown without media at all. Though, if you want to mount a Tolumnia, a cork or tree fern mount is ideal.
• Indoors, plant in either 100% treefern fiber or 1/3 sphagnum and 2/3 fine orchid bark mix or treefern fiber (or both).  Mounting and placing in a high-humidity terrarium or vivarium works as well.

Tolumnia need to be divided and repotted every few years to mimic how their naturally stormy native environment affects these plants. They have evolved to grow more when disturbed every year to few years.

Further information can be found on the Tolumnia genus page.

Best orchid care practices are also provided for watering, repotting, and fertilizer types. There are also detailed discussions of growing orchids indoors, outdoors, or in greenhouses.

For more information on genus name changes, see Taxonomy.