Root Bound Orchids:
5 Important Things You Need to Know
One of the differences between Phalaenopsis orchids and other household/indoor plants is that moth orchids need to be repotted every two to three years—other plants enjoy their potting soil for much longer periods. The potting medium that Phalaenopsis orchids live in degrades rapidly. When the media decomposes, it attracts bacteria, fungus, and gnats, eventually causing the decay and rotting orchid roots.
Image credit: Orchideria ©2020 All Rights Reserved.
Repotting a Mini Phal that was rootbound. In this case, the roots were so tightly packed that they were suffocating each other, causing the orchid to slowly die. Usually I would not repot when the orchid was in bloom, but in this case, the orchid would not make it if I had waited.
Moth orchids need to be in fresh media to survive, repotting with fresh media every other year.
On the other hand, orchids like to fit snuggle in their pot. This appears to be a contradiction, having a plant that both enjoys to be root bound and also needs to be repotted frequently.
Do Phalaenopsis orchids like to be root bound? Phalaenopsis orchids appreciate being root bound, providing that enough air circulation is still present to promote proper gas exchange. There is a limit to how much a Phalaenopsis orchid prefers to be root bound though. When no circulation is present inside the pot due to being root bound, the Phalaenopsis roots become intoxicated with disrupted gas levels and suffocate, promoting root rot.
What is a rootbound Orchid?
A root bound orchid is one that has grown out all the available space in the pot, so the roots grow toward the outside of the pot. Overgrown orchids inside tiny pots seem like roots are growing in all directions, even outside the pot.
Phalaenopsis orchid roots need to be compacted and compressed inside their pot, and unlike other household plants, Phalaenopsis actually enjoy being root bound. This is not to think that areal roots are a sign of a root bound orchid; they aren't.
What are the signs my orchid is Rootbound?
Areal roots never grow down into the potting media and should not be forced to grow there if they decided to grow on the outside of the pot. Don’t cut the areal roots either. They provide just as much nutrition and water to your orchid as the roots inside the potting media.
Depending on how degraded your potting media is, the areal roots might even be providing more nutrition than potted roots do.
It might be tempting to think that only over-watering promotes root rot, but the truth is that the roots will start rotting due to the gases they can’t exchange. This chemical imbalance creates toxicity that kills the roots.
Root bound Phalaenopsis roots are tightly enclosed by potting media yet still have proper air circulation inside the pot is the target you want to achieve when cultivating orchids. As long as your Phalaenopsis orchid can still have air circulation, they will thrive by being root bound.
You already know that orchids like to be root bound, but how can you do that if you change the media every other year? The secret is in the size of the pot you use to repot. By selecting a pot only an inch (2.5 cm) above the previous pot, you can provide ample room for root growth yet also give the orchid the sense of being tightly snug inside the pot.
A common mistake when thinking your orchid is root bound is to select a humongous pot, thinking that ample space for root growth will promote better and healthier conditions for orchid growth. That doesn’t work.
Why do Phalaenopsis Orchids Enjoy being rootbound?
In nature, Phalaenopsis orchids grow attached to the bark of trees, living under the protection of overhead leaves. In the deep uncharted paths of subtropical and tropical rainforest, Phalaenopsis have clung to tree bark, not as parasites, but to soak up the filtered sunlight that speckles through the leaves.
They also get a good breeze, as wind floats through the slender tree trunks of the forest. They don’t live in the soil, or near the bottom of the forest.
Phalaenopsis orchids also don’t have the imitations that they do inside a pot.
This brings us back to being root bound. If they grow with wild roots spreading freely in the air, why do Phalaenopsis orchids like to be root bound when brought inside our homes and placed in a pot?
The roots of a Phalaenopsis have tiny white “freckles” that are what attaches to the tree bark when grown naturally, and what also clings to the inside of the pot.
They hold on to the tree trunk for dear life, and the sense of security will provide them with the conditions to properly promote leaf and spike growth.
Image Credit: "Cattleya labiata" by Tarciso Leão is licensed under CC BY 2.0
When they don’t feel like they can cling onto something, they have no protection from animals that will run across tree limbs, or heavy rainfalls which common in the rainforest. Strong winds will also gust through the trees, and if the roots are not secure, they’ll fall onto the forest floor, where little nutrients are found.
It’s a common mistake to think that the soil is rich in the rainforest, but that’s not so. Since hardly any sun reaches the soil and constant leaching of minerals and nutrients occur due to heavy rainfalls, the soil is actually poor.
Hardly anything grows on the soil in the subtropical and tropical forest—much less orchids. Some orchids have adapted to thrive in these conditions and grew terrestrial roots. They were later classified as terrestrial orchids, like Paphiopedilums or Lady Slippers.
Phalaenopsis orchids are epiphytes, which by definition means growing on trees—not terrestrial.
This is why the Phalaenopsis orchid needs to rootbound. It will sense that the roots are strongly attached to the sides of the tree/pot and can be carefree, focusing on growing new leaves and a flower spike.
Characteristics and Specific Needs of a Root bound Orchid
When your Phalaenopsis orchid is root bound, it will absorb more water, and will also absorb water faster. This means that you will need to water more frequently than a moth orchid that is potted in sphagnum moss, fir bark, perlite, and charcoal.
These extra components in the potting medium will absorb water and slowly release the humidity into the medium. When little potting medium is present, mainly being roots in the pot, there will be less absorption by media and more by the roots.
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How to Repot a Root bound Phalaenopsis Orchid
The hard part of a root bound Phalaenopsis orchid is when it comes to repotting. The velamen, a thin silver-green, paper-like structure that covers the roots, attaches to the pot and can rip and break when a rootbound Phalaenopsis orchid moves around in the pot.
When the roots start to peep out of the side of the pot, through the ventilation slits, and drainage holes, the chances to damage roots are high.A root bound Phalaenopsis orchid needs to be soaked in a bucket of water for around 20 minutes prior to repotting.
This has two advantages:
1) the roots become more manageable and can bend and flex easier without tearing, and
2) the media absorbs the water, and its surface becomes smooth, adhering less to the roots.
If your pot is flimsy, squeeze the pot in all directions before you pull the root bound Phalaenopsis orchid out of its pot.
This action releases the attached velamen without causing a lot of damage.
Gently wiggle the orchid out of its pot, turning and sliding it. Never tug with a firm yank, as the roots will break.
There is an upside to having a root bound Phalaenopsis. If you happen to break and tear a few roots, the orchid will not mind. There will be so many other roots that it can survive happily without feeling the loss.
The downside is that if you wait too long before repotting, the lack of air circulation in the root bound orchid will lead to an increase in dead roots.
If you want a more in-depth article of how to properly repot an orchid, whether it’s a Phalaenopsis, Cymbidium, Oncidium, or Cattleya, check out this article.
I went into a lot more detail in that article about the specific care of repotting orchids.
Further Reading Suggestions:
Don't just take my word for what is written here. Continue researching other articles about root bound Phalaenopsis orchids
, because everyone has a different point of view and unique techniques that work for them. Here are a few other articles from other websites if you'd like to continue your research on root bound orchids
- "Physiological diversity of orchids"
Shibao Zhang ,
published on Plant Divers. 2018 Aug; 40(4): 196–208. (Published online 2018 Jun 25. doi: 10.1016/ j.pld. 2018.06 .003)
talks about the properties of orchid roots. They state that, "Epiphytic orchids have modified aerial roots that are sometimes more
than 1 m long. They also feature a velamen that consists of dead cells.
This velamen covers the entire root except the tip, and functions in
rapidly absorbing moisture and nutrients from the surrounding humid
-"Caring for Phalaenopsis orchid"
written by Dave Clement,
Ph.D., Extension Specialist, Plant Pathology and Mary Kay Malinoski,
Extension Specialist, Entomology published by the University of Maryland Extension
, states that, "In nature, Phalaenopsis orchids grow on tree trunks and branches in the warm sections of the tropics worldwide. They tend to hang on tree bark, and send out aerial roots along their stem. For this reason, most of their roots will be above the pot and will commonly sprawl outside the container and even along the shelf surface. This is perfectly normal so do not cut them off.
-You can also check out a full tutorial on how to care for Phalaenopsis Orchids in this article