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How To Repot Orchids With Air Roots

Written by Patrick Chism in How To

Published: September 22, 2021

Updated: February 25th, 2022

repotting orchids

As an orchid grower, you’ve likely seen roots poking out of the soil beneath your gorgeous blooms. These aerial roots are a pretty common sight with some orchids, and some growers will tell you that this means you need to repot your plant. But is that actually true?

This article will teach why this phenomenon happens and how to repot orchids with air roots.

But before we get into that, we’ll explain a bit about what aerial roots are, which orchids have them, which conditions they’re found in, and how they are affecting your plant growth.

What Are Aerial Roots?

Aerial or air roots are orchid roots that grow outside the potting media. In the natural tropical habitat of orchids, aerial roots are a common way they receive moisture and nutrients and anchor themselves to trees. Orchid air roots, which sometimes cling to the outside of the orchid pod, indicate that the plant is in good health, so it’s commonly recommended that you don’t prune or bury them.

Some epiphytic orchids hang their roots in the air to collect water, which they receive directly from the atmosphere, rain, and water that drips off foliage above them. Others stretch their roots across the surfaces of tree branches, collecting water or other nutrients when they drip from the branches.

What Does Epiphytic Mean?

An epiphyte is a plant that grows on another plant – often a tree – but they don’t have a truly parasitic relationship. While a parasitic plant would draw its nutrients from the host plant itself, the epiphyte uses plant debris from leaves and water on the host. 

Epiphytes are often found in tropical or temperate areas, typically in denser shaded areas. They climb their hosts as a way to access more sunlight.

There is a wide variety of epiphytic plants, including orchids, some ferns, mosses, and bromeliads. Nearly 90% of all epiphyte species are flowering plants, such as orchids.

Epiphytes are usually good as indoor plants, as they have lower light needs, lower nutrient needs, and generally pretty low maintenance. The key requirement for these plants is usually humidity. 

Why Do Some Orchids Have Aerial Roots?

In their native tropical habitat, epiphyte orchids pull nutrients from the atmosphere through their aerial roots. They also collect moisture from the air, anchor the plant (usually to a tree) and obtain carbon dioxide needed to thrive.

High humidity is key to survival for these epiphytes, which is good to remember if you attempt to grow them indoors. An orchid’s root system inside a pot is usually pretty weak and often decomposes in a growing medium (potting mix). But the aerial roots are typically white, healthy, and a primary source of moisture and nutrients.

Photo by DIY Network

Orchid Root Information

Orchid roots are covered in a substance called the velamen that behaves like a sponge, absorbing up water. The velamen likewise protects the roots. 

The velamen transports water to the stele, which supplies nutrients to the pseudobulb (if one exists), stems, and leaves.

White roots and light brown roots are usually signs that your orchid is healthy. Brown, mushy or black roots are signs that it’s dying, and you need to change your care routine.

What Does It Mean When Orchids Have Lots Of Aerial Roots?

Several air roots on an orchid can mean a few things. First off, they could simply mean that you have a healthy orchid trying to absorb water and nutrients from the air, as it would in its natural habitat. 

Why Should You Repot An Orchid?

The primary reason for repotting an orchid is to protect the root development from degrading potting medium. Overcrowding of roots is a possibility, but it’s not why you see air roots. Aerial roots are a natural feature of these epiphyte orchids. They shouldn’t be stuffed in a pot, as their primary function is to draw nutrients and water from the air.

The growing media we plant orchids in, though, is especially prone to causing root rot or diseased roots. So the reason to change out the pot is to refresh this sphagnum moss, orchid bark, charcoal, etc. 

And when repotting, if you see fungus or disease, it’s a sure sign that you have rotten roots!

All of these are reasons you should repot your orchid plant. And as an added bonus, it can help you produce encore blooms.

Types Of Orchids

While not all orchids have aerial roots, there’s a pretty good chance your orchid has them if you’re reading this article. There are typically considered three different types of orchid species. They are grouped as terrestrial orchids, lithophyte orchids (rock-growing orchids), and epiphyte orchids (tree-growing orchids).

Let’s briefly discuss some of the terminologies around orchids, including monopodial vs. sympodial, epiphyte orchids, and just some common orchid species.

Terrestrial Orchids

Orchids that grow on the ground are known as terrestrial orchids. Some have underground roots, although the majority develop from pseudobulbs. These orchids do not have aerial roots. 

There are around 200 kinds of terrestrial orchids, and their care differs from species to species. Some of these cold-weather orchids, known as hardy orchids, are deciduous, shedding their leaves in the winter and producing new ones in the spring.

Lithophyte Orchids

Lithophyte orchids are orchids that exclusively grow on rocks and do not grow on trees. The phrase is derived from the Greek terms litho-, which means stone, and phyte, which means plant. In other words, it’s a plant that lives on rocks. 

They’re frequently found near the roots of trees or in cracks on rocky hillsides, where debris collects. They use the nutrients from this debris, as epiphyte orchids would in trees.

Lithophyte orchids have either aerial roots and a pseudobulb and aerial roots – or just a leafy stem and aerial roots.

Lithophytes are typically considered rare and difficult to grow.

Epiphyte Orchids

Epiphytic orchids affix themselves to other plants, usually trees, and their relationship with their host is non-parasitic. They typically have aerial roots and obtain their water and nutrients from rain, air, and other debris from the surrounding area.

Epiphytes are found in bromeliads, ferns, orchids, and a variety of other plant groupings, accounting for about 10% of all plant species. The needs of epiphytes differ from those of their terrestrial counterparts.

Orchids have had to adapt to wet and dry cycles because natural rainfall isn’t predictable. Pseudobulbs, which specialize in water storage, are also seen on some epiphytic orchids. Pseudobulbs make it easier for these plants to withstand drought.

Monopodial Orchids

Monopodial orchids have leaves and flowers that grow from a single stem. It may also have a separate stem called a basal Keiki, which is not considered a full orchid but could become one.

Most phalaenopsis and vanda orchids are considered monopodial.

Sympodial Orchids

Monopodial orchids have a single root system, unlike sympodial orchids. This means that the only way they absorb nutrients is through this single root structure, which may include aerial roots.

While a Monopodial orchid has air roots, sympodial orchids have multiple bulb root structures that don’t grow upward in the same way.

Spider orchid with aerial roots Photo by Peter Trelford

Common Orchid Varieties 

And before we dive in any further, here are some common types of orchids. They’re a good refresher in case you’re just getting started in the orchid-growing space.

Phalaenopsis Orchids

Often called moth orchids, these orchid species are easy to care for and can boom most of the year. There are many orchids in terms of color, from the white orchid to the pseudo-blue orchids that are becoming increasingly common in stores. Even if you’re new to the orchid growing space, you’ve likely seen a Phal before.

A Phalaenopsis orchid is typically considered an epiphytic plant with aerial roots.

Cattleya Orchids

Sometimes called the queen of orchids, Cattleya orchids are considered among the most beautiful orchid flowers. They are also typically regarded as epiphytic plants with aerial roots.

Vanda Orchids

These orchids grow terrestrially or epiphytically, so they may or may not have aerial roots. These beautiful plants often have been seen in markets with roots hanging downward or upward outside of a pot. 

Cymbidium Orchids

Often considered cold-tolerant orchids, Cymbidiums are often known for their bloom during the middle of winter and flower spikes that can last 1-3 months. These are typically considered epiphytes and have aerial roots.

Dendrobium Orchids

There are a vast number of Dendrobium orchids out there – over 1400 species have been cataloged. There are both Dendrobiums with air roots and terrestrial Dendrobiums without air roots.

When To Repot Your Orchids

The root structure and health are the most important reasons you want to repot your orchid. Orchid growers should repot when they first purchase the orchid, when they’ve had it a year or two, or when the roots become overly crowded.  

If you’re using a pure sphagnum moss, it degrades quickly, meaning you’ll need to repot more often. Orchid growers using orchid bard or charcoal can wait longer between repotting, as these growing mediums can last 2-3 years. That said, it’s usually a little more challenging to repot with these larger growing media.

When moving to a larger pot, only go up a single size if possible.

Orchid stem rot photo from AskGardening

But How Do You Know If Your Roots Are Overly Crowded?

The best way to verify if your roots are overcrowded is to check them. If you notice that the roots have become tightly tangled or they are showing signs of rot – they look a sickly brown color if they’re rotting and they are soft – it’s probably a sign to repot. 

That said, don’t expect the roots in the soil to look as good as the aerial roots. After all, in nature, orchids don’t grow in pots. Epiphyte orchids just grow straight on the tree, and their roots are exposed for all the world to see.

So when analyzing your roots, you shouldn’t immediately panic if you notice the roots in the soil are in worse condition than the aerial roots. That’s to be expected. 

But if you see signs of rot, that is a good indicator that you need to repot. According to Cornell University, with proper water, you should only need to repot every year or so. This is around the time that the soil or other growing medium starts to break down, which can actually smother your roots..

Should I Repot An Orchid I Just Bought?

The main reason you should repot your orchid after purchasing is if you expect the seller doesn’t quite know how to grow orchids (or keep them alive once they’re off the shelf). Sadly, this is the case in most situations.

A good thing to look for is the pot. If you don’t see drainage holes in those beautiful pots that most Phals come in, it could be a sign that your seller doesn’t know squat about orchid growing. 

Similarly, there’s no guarantee that the growing media used by the seller is fresh – or made with high-quality material. Another common issue with buying from a greenhouse or orchid mill is that they pack the moss too thickly, meaning the water doesn’t drain as well.

The safest bet is to (gently) repot your orchid into a pot with drainage holes, using an orchid mix growing media that supports good drainage.

The Best Time To Repot Your Orchids

When repotting your orchids, the best time to do it is right after flowering has started – or when you see new growth appearing. While a bit variable, a wide variety of orchids bloom almost any time of year. Typically, though, the growing season for an orchid is summer, and they bloom in spring, fall, or winter. 

Some growers suggest that you wait to repot until you see root tips in the growing media, which are easier to see if you’re using a glass or clear plastic pot.

Some orchid varieties, such as Cattleyas, grow consistently throughout the year, meaning it’s usually easier to repot them without causing too much stress. Other orchid types have only a single time of the year when they’re actively growing roots. And if you don’t repot them during this time, it could affect their blooms for years to come.

Again, it may depend on the specific orchid cultivar, but most orchids don’t like to be repotted in colder seasons. If you’re growing your plant inside, you can help mitigate winter-like conditions.

What Size Of Pot Do You Need When Repotting Orchids?

You want to move up to a larger pot when you repot an orchid, assuming you’re repotting due to growth. If you’re repotting to fend off root rot, or you just bought the orchid, you don’t need to worry much about it yet.

Steps To Repotting Orchids With Aerial Roots

So if you’re ready to repot your orchid with aerial roots, here are the steps you should take for success.

Step 1: Remove Orchid From Pot

To remove the orchid plant, gently turn the pot upside down, holding the plant to allow it to fall into your hand. If your orchid is too large or heavy to carry, you can also put the plant on its side and coax the plant out.

Step 2: Remove Outer Growing Media From Around The Orchid Roots

When the orchid’s roots are out of the pot, they will likely still hold most of the growing media in place, especially if the primary component of the media is sphagnum peat moss.

You can typically pull tufts of the growing media out of the roots without causing damage. Remove as much as you can with your fingers without damaging the roots. Several growers recommend that you use gloves to keep any potential bacteria away from these roots.

Step 3: Using Tweezers, Remove The Inner Growing Media From Around The Orchid Roots

Using thin tweezers with pointed ends, remove the old potting medium from the roots. These tweezers will help you grab the pieces of moss or orchid bark from the roots. It’s like playing Operation! 

You want to get the media out carefully. Again, if you’re not careful, you could damage the roots. Orchids are a time-consuming hobby! Take your time, so you don’t hurt your precious orchids.

Step 4: Rinse And Soak Your Roots

Once your orchid has most of its growing media removed, rinse and soak roots for 10-15 minutes. During this point of the process, be sure that the water is lukewarm (room temperature water to slightly warm water) and is only interacting with the roots and not the stem. If water gets in the stem, it can cause rot.

Step 5: Remove Decaying Roots And Rotting Roots

If you see rotten or damaged roots, carefully remove them with sterilized garden scissors or other cutting tools. Leave healthy roots (which will be light, bright, and firm) alone.

This is also an excellent time for reflection. If you see several rotten roots, it means that your orchid is sitting in water too often. This is a sign that you need to have a better-draining growing media or that you need to replace your growing media with a greater frequency.

Step 6: Sterilize The Roots

If you cut away any dead roots or dying roots, treat them each with a few drops of either cinnamon or hydrogen peroxide 3%. 

Step 7: Repot

Place your orchid back in the middle of the pot. At this point, there will only be an orchid in the pot – no growing media. You shouldn’t force the bright white aerial roots into the pot.

If your orchid has grown and you want to give it a larger pot, only go up to a size that’s 1-2” bigger than the previous pot. 

Step 8: Change Out Potting Medium

Gently place growing media around the roots in the pot. Sphagnum moss, an orchid potting mix, coconut fiber, bark, or some combination of these elements typically work well for this.

Step 9: Watering Transplanted Orchid Plant

The general rule of thumb is to wait a week after transplanting to a new pot before watering. At this point, it’s okay to water orchids as you normally would.

Want to learn more about houseplants? Check out our care guide for marble queen pothos.

What Soil Do You Need For Epiphyte Orchid Repotting?

So as we mentioned previously, epiphytic orchids don’t grow in soil like their terrestrial cousins. If you’re new to the orchid plant game, I highly recommend you just buy potting media specially designed for orchids.

The main ingredients will likely be charcoal, perlite or sand, sphagnum moss, pieces of bark and coconut fiber or husks.

Orchid lovers will tell you that the key tenant of orchid care is good drainage. Never forget – you’re trying to emulate their natural growing environment. And their orchid tendrils don’t enjoy standing in water. They are incredibly susceptible to root rot. So whatever growing media you use needs to provide elements that support this drainage.

Here you want to make your own orchid potting mix.

  • 3 parts orchid bark (fir bark is fine)
  • 1 part perlite
  • 1 part sphagnum moss

We should point out that this is not the only option available, but it will certainly get the job done. Other growers recommend just using fir bark and sphagnum moss. But again, as long as you have proper drainage, you can mix and match as you see fit.

You can also grow orchids via semi-hydroponics, often using LECA balls as your growing medium.

What Type Of Pot Should You Use To Grow Orchids?

While the drainage is likely the most important factor for orchid grower pots, people are always asking if there’s a special pot type that orchids prefer. And while you could grow in plastic pots or clay pots, an orchid pot is often made of glass.

Glass pots are usually the fan-favorite because they’re supposed to emulate the way that these plants’ roots are exposed in the wild. In nature, their aerial roots are exposed to indirect sunlight – much like the rest of the plant.

That said, having a pot at all is not truly a natural way to grow an orchid. In the wild, they don’t have a pot – glass or otherwise – and the air circulation and humidity access are incredibly important factors for this plant.

Drainage Holes

I know I’ve said it a few times in this article, but seriously, make sure there are proper drainage holes. Before you buy anything, check the bottom of the pot. If it doesn’t have holes, let it be. Orchids are church-going plants. They like their pots holy. 

How Much Water Do You Orchids Need?

Like many plants, you want to balance the amount of water you give your orchid plant – too much water can easily cause root rot, while not enough water can damage the orchid or slow down growth. The amount you water an orchid varies depending on several factors, but you typically want to water every 1-2 weeks.

Should You Use Ice Cubes To Water Your Orchid?

I know you’ve probably seen directions on the store-bought orchids that tell you to use an ice cube. But would a Phalenopsis orchid in the tropics really depend on an ice cube, much less ever experience frozen water at all? 

This doesn’t do your plant any favors and can end up causing damage to your orchid. It’s best to use tepid water (lukewarm over 60F) paired with well-draining soil.

Conclusion

While aerial roots may seem strange to indoor growers, they’re the sign of a very healthy epiphyte orchid. Instead of cutting them away or shoving them in a pot, let them do their thing! Sure, if you want to snip a few, that shouldn’t cause significant damage, but embrace the aerial root aesthetic. Air roots are just one of the many orchid attributes that make these plants fascinating!Are you growing this beautiful epiphyte with aerial roots? We want to see it! Please send pictures to [email protected], and we may highlight them on our site!

Patrick Chism

Learn More About Patrick Chism

Patrick likes to pretend that urban gardening is just a hobby, but he’s actually prepping for the apocalypse. He’s a practical grower, specializing in hydroponics systems and grow lights. His dream is to one day feed his family with just the food he grows in his Chicago-based condo.

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