Tolumnia have a unique charm of their own and are sought after by orchid enthusiasts for their attractive blooms and small size. The first thing that comes to your mind when you think about Tolumnia orchids is that for their compact size, these small and  delicate blooms pack a punch when they bloom in multiples, in all their vibrant glory.

Orchid hobbyists love Tolumnia orchids for the following reasons:

• Their blooms are beautiful and come in the most versatile of colours, patterns and combinations.
• They are preferred for their compact sizes and grow well on mounts. So more plants can be accommodated in the grow space.
• They are relatively inexpensive and affordable.
• They mature very quickly. In two and a half years, they develop from a flask to blooming size.
• The inflorescence sequentially blooms to produce new blooms on old spikes. So the spikes should not be cut, unless they dry off fully.
• Since Tolumnia are epiphytes and can attach and grow on various substrates, you can experiment with different types of material and display them in beautiful settings.

Appearance

The plants grow to a height of 6-8 inches, with inflorescences measuring up to 8-12 inches or more. With their thick succulent leaves and beautiful fans, the plant looks refreshingly beautiful, even when not in bloom.

New fans arise from the older ones, thereby appearing to be astride the older fan. This was why they were earlier referred to as Equitant Oncidiums. However, except for the flower shape, which is similar to the dancing Lady oncidiums, they have very little similarity with oncidiums and on the contrary, share characteristics with vanda orchids, particularly in their fan type of structure or in their preference to growing bare root in high light conditions.

Growth habitat

In their native Caribbean habitat in the Bahamas, as well as places such as Florida, Cuba, Peurto Rico, and other places, Tolumnia orchids are found growing on thin peripheral branches of trees. This points towards their preference for bright, diffused sunlight, getting drenched in the rains and quickly drying up from the trade winds that are constantly blowing. The roots are hairy, with a thin covering called velamen, which absorbs moisture from the air.

Care requirements

To grow Tolumnia successfully, we need to keep these culture preferences in mind and mimic these conditions in the best possible way.

Growth medium

At the very outset, one thing is clear – Tolumnia orchids prefer a quick wet and dry cycle. They do not like being wet for prolonged periods, which is why many times, rot issues set in when grown in pots with organic media.

A more conducive environment would be to grow them on something rather than in a pot. Most hobbyists prefer growing them on mounts as this significantly reduces the risk of rot issues due to moisture retention. However, this means that the mounts need to be watered/misted daily once or twice, depending on the climatic conditions, which can get a little tedious at times.

Many hobbyists have successfully grown Tolumnia using a coarse and well-draining medium. This ensures that the roots get adequate moisture without remaining excessively wet.

The trick here is to use small pots with a minimal quantity of coarse medium, or alternatively, grow them bare-rooted in terracota pots.

The moisture retained in these pots is sufficient to help them grow well. Ensure you choose a small-sized pot so that it can facilitate a quick wet-dry cycle. A 4-inch pot can hold a specimen-size Tolumnia plant.

Personally, I have had little success with this method. I tried growing my Tolumnia in pots, especially so that I did not have to water them everyday, but they did not respond well. I also faced rot issues despite using coarse bark chips. Not one to give up easily, I switched over to mounts and they have been doing very well, without any issues.

I prefer mounting my Tolumnia for a number of reasons, the first one being that they are growing in near-natural conditions. The second reason being that they do not have rot issues. Watering daily is hassle-free as it does not take me more than five minutes to water my wood mounts. My Tolumnia  seem to like it, and respond favourably by blooming year after year.

Light

Tolumnia prefer bright, diffused light similar to Vandas and Cattleya, so you can place them where they get bright indirect light or morning and evening sunlight, which is mild.

Tolumnia that receive a good amount of light have light green leaves, while those that receive less than adequate light are dark green in colour. You can judge whether they are receiving adequate light by checking out for a purplish tinge on the periphery or tip of the leaves. If the purple tinge is pronounced, then you need to reduce the light intensity for providing optimal conditions.

I hang my wood-mounted Tolumnia on my window sill, wherein they receive bright, indirect light. They seem to like it and produce multiple new growths and bloom twice a year.

Temperature and humidity

Tolumnia can tolerate heat well, provided they receive air drafts and adequate humidity. This is why they grow on the peripheral branches of trees in the Mediterranean climate. In your home, you can grow them well at moderate a temperature of 55° to 90°F with a humidity of 50-70%. Placing humidity trays close by can help them meet their humidity requirements to grow well.

Watering

Since Tolumnia are thin rooted and small in size, their water requirements are considerably low.

If you are growing your Tolumnia in pots with coarse medium, you just need to wet the medium and ensure the excess water drains off fully.

This exposure is sufficient for meeting its moisture requirements. If the medium remains wet for a longer duration, the excess moisture will create conditions that promote rotting.

Also important to note is that only the roots should be damp. Water should not get into the base of the fans as this can lead to rotting of the leaves and fans.

This can be achieved by dipping the pot in a bowl of water, all the while ensuring that the level of water does not touch the base of the fan or rhizome. The roots should, however, be submerged in water. Once the medium gets wet, you can quickly remove the pot from water and allow the excess water to drain out into a shallow plate or tray. Allow the medium to dry fully, before watering the Tolumnia again.

Watering your wood-mounted Tolumnia is much simpler. All you have to do is spray water every day or just hold it under running tap water and wet the roots. If water gets into the fans, ensure it dries off quickly by blotting it with tissue and placing it under a fan. Alternatively, hang it on your window sill and allow the breeze to dry out excess water quickly.

Your wood-mounted Tolumnia will dry out quickly. Depending on your climatic conditions and humidity levels, during summers, you may have to water them twice a day, if you find the leaves getting limp and dehydrated. You could also temporarily attach an extra amount of loosely packed sphagnum, which will provide the right amount of humidity to combat hot air drafts.

The rains will bring out the best in your wood-mounted Tolumnia. All you have to do is hang them out in the rain and allow them to soak in it.

If the rain is heavy, then remove them and place them in a protected area until they dry off. If there is alternative wetting and drying from breeze, then you can leave them exposed to rainfall. To allow them to dry off quickly, reduce excessive sphagnum moss, which you placed to provide adequate humidity during summers.  

Fertilizing

Once a week, you can make a weak fertilizer solution by applying half the recommended strength of fertilizer solution for your Tolumnia. I use a combination of NPK 20:20:20, Calcium Nitrate and Magnesium Sulphate.   I dilute it to a concentration of 110 TDS and apply it once a week. Once a month, I apply bloom booster fertilizer at a concentration of 110 TDS. This combination brings out the best in my orchids.

Cool winter rest

Just like your dendrobium nobiles, catasetums and some other orchids, Tolumnia respond well to a cool winter rest. During the rainy season, they soak in its goodness and grow vigorously. This prepares them for the prolonged dry spell during winter.

I resort to watering them once a fortnight from October to mid-February. This ensures they slow down active growth, just as they do in nature. By providing these conditions, they conserve their energy for the blooming season in spring.

One need not worry about the orchid suffering from the neglect. The growth spurt in the rainy season ensures that the orchids remain healthy despite minimal watering. You can occasionally water them so that they do not get dehydrated and desiccated, but keep it to the minimum for better results.

Displaying your blooming Tolumnia orchid

Due to their compact size, Tolumnia work well for using them in terrariums that are well-lit. They can also be displayed as part of larger arrangements in combination with other plants. To learn more about displaying Tolumnia, read my posts on Project#3: Displaying your blooming Tolumnia orchid

I constantly experiment with new ideas and try to mount them either singly or in combination with different coloured Tolumnia. To learn more about this subject, red my post, Project#2: Mounting your Tolumnia orchid on wood.

In one such community planting project, I have mounted seven different Tolumnia on a single mount. While some of the plants have bloomed, I eagerly await the day when all the seven plants will bloom together, creating a stunning display of vibrant colours and patterns.

I recently planted a tiny Phalaenopsis hybrid (Phal. equestris X Phal. lindleni) along with a Tolumnia orchid on the same mount. While both have different requirements of light, watering and fertilizer, I am confident that their needs can be managed reasonably well. I will keep you posted on their adaptation to the mount and their growth response.

There are many ways in which you can experiment with new media and substrates for your Tolumnia. This is what makes orchid growing so exciting.

Until my next, happy growing!