Air roots in orchids - this is how you handle them properly (including dried-up, withered aerial roots)

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Orchidaceae - Orchids Vanda

Many orchid species produce aerial roots. These are mainly the epiphytic orchids, especially the species of Phalaenopsis Orchids. Epiphytes are potted plants, plants sitting on other plants. The aerial roots absorb water and nutrients. They also give them a hold on the branches of their host plants. Orchid friends pay as much attention to the aerial roots as the rest of the plant. Proper handling of the roots is important for healthy leaves and lush flowering.

Function and appearance

The aerial roots of potted plants have the special ability to absorb water and nutrients from the air. A sponge-like cell layer (Velamen radicum) ensures the uptake and storage of vital bases. This special outer cell layer absorbs the water and mineral salts from the air, dust and rain. Through their stable and adaptable structure, the aerial roots provide the orchids with a secure hold on their host trees and shrubs. According to their abilities, they are also called adherent roots or respiratory roots. In the orchids, which are cultivated as indoor plants, the roots provide sufficient support in the substrate. The less nutrients and water they get over the substrate, the more they develop cross-growing air roots outside the vessel. In some orchid species, the roots shimmer slightly greenish, they are chlorophyll-bearing. As a result, even in times when there are few leaves due to climatic conditions, they are still able to process the nutrients. Branches hardly show the roots of the orchids, but they like to grow criss-cross. At the end of the respective vegetation period, a new formation of roots takes place.


If you want to find out which roots are still alive and healthy, you can best check this by spraying the roots with water. Then most of the roots turn green. In addition, it is easy to see if water is being absorbed because color and shape change slightly. The roots should have a firm and smooth surface.

Lazy roots

Too much moisture or constant watering into the heart of the orchid can cause the roots to rot. The rotten roots must be removed. If there are enough healthy roots left and you keep the plant a bit drier in the future, it will be able to recover completely.

Dead, withered roots

That roots die off over time is normal. It is not necessary to remove them immediately, they can often serve as a support for the orchid. With the water sample you can see which roots are already dead (ie completely dry) and can remove them if they get too much or visually disturb them. Roots that look dry should not be removed immediately. Maybe too little (air) moisture is the reason. Often they get green tips again, once you increase the humidity. Regular spraying or a nearby vessel of water can help to revive the roots, provided they are not completely dead.


Orchidaceae - Phalaenopsis orchids

To ensure the highest possible humidity, sprinkle the orchid, including its aerial roots, with fine fogged with stale water. Of course, this process does not replace regular watering. It is best to spray in the morning so that the water can evaporate during the day. The mixture with the liquid orchid fertilizer can also be sprayed on the aerial roots with a spray bottle.

To cut

Basically, you should never just cut around on the aerial roots of an orchid. Only dead or rotten roots are removed professionally. It may rarely be necessary, for reasons of appearance or space, to remove healthy airborne roots. In this case, only a few strands per plant may be removed, otherwise it will not be sufficiently supplied and the orchid will die. Most of the time, a healthy orchid outside the substrate does not form more roots than inside. Too many aerial roots are a sign that the orchid is no longer getting enough moisture or nutrients through the substrate:
  • This can be due to the substrate. Maybe it is too old, already rotten and has concentrated on the roots. Remedy by immediate repot in fresh substrate.
  • Or the plant just does not get enough moisture and nutrients. Here it helps to give more water and fertilizer into the substrate.

Separation of aerial roots:

  • The tool (knife, scissors) must be sharp. This prevents fraying of the interfaces. An orchid knife or a scalpel-like knife is preferable to a pair of scissors.
  • The tools are first disinfected with boiling water or high-percentage alcohol. This reduces the risk of germs invading the interface.
  • The best time for the cut is the time of rest. The time after the flowering of an orchid.
  • The interface, which is considered an open wound, should be brushed with coal powder immediately after the cut. This reduces the risk of fungi gaining access from there.


If the substrate is used up after two to three years, the orchid is repotted. Also relatively many air roots are a sign that needs to be repotted. This is also the best opportunity to remove dead or decayed roots. After replenishing the plant, carefully remove the old substrate from the roots. So that no roots break off when inserting into the new substrate, put all roots, including the aerial roots, in lukewarm water for up to 10 minutes. They become so supple and do not break when moving. In the new pot, carefully turn all roots (including the aerial roots). Then add the new substrate.
Tip: Never choose the new pot too big. The most important thing about repotting is the new substrate. In small pots, the roots have a better grip. If you choose a transparent pot, more light comes to the roots and you have them better in view.


Orchidaceae - Phalaenopsis orchids

Different types of orchids also form different roots. So not all orchids are suitable for pot culture, not all form aerial roots. The thickness and nature of an orchid's roots allow conclusions to be drawn about their specific needs.
Dracula, Masdevallia
These species form very thin roots (up to one millimeter), they require a lot of moisture and must never dry out completely. The roots can be placed in a substrate, but also grow outside.
Dendrobium, Oncidium
The roots of these species are still quite tender with up to 3 mm diameter. They form many aerial roots, but can be better cultivated in the pot with us. They love it wet and rather cool.
Cattleya, Phalaenopsis
The roots are up to 6 mm thick. Mostly they are cultivated here in the pot. Many aerial roots are more a sign that the plant needs new substrate.
Aerides, Vanda
The aerial roots of these species grow thick, sparse and are not cultivated in pots. You do not need too much moisture. In their Asian homeland the morning and evening dew are enough for them. The genus Taeniophyllum has flattened, chlorophyll-containing aerial roots. These are able to take over the function of leaves. They need the light.
Paphiopedilum, Phragmipedium
Using these species is not easy. The roots are hairy and are cultivated in soil. They do not form aerial roots. Be careful when repotting, the roots are very sensitive and break easily.
ConclusionNot all orchid species are really easy to care for. Anyone who would like to enjoy their orchids for a long time will sooner or later have to deal more intensively with the special needs of these particular plants. Proper handling of the aerial roots is one of them. The most important rule, in order not to do anything wrong here, should be: Healthy air roots are not simply cut off. High humidity, good nutrient supply and regular fresh substrate, that is already a good basis for healthy orchid roots.

Video Board: Q&A - How to care for aerial roots on Phalaenopsis Orchids?.

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