If you’ve asked the question above, you are not alone! Let’s first geek out a little about words and define “aerial roots.” The prefix “aer-” is derived from the Latin word aer, which means air. So the word aerial itself is the key to unlocking the meaning. In orchids (as well as many other plants), aerial roots are roots that grow from the base of the plant upward, or out into the air, rather than down into the soil or inside the pot.
What is the purpose of aerial roots? Well, a great many types of orchids, including the most popular household orchids—Phalaenopsis—are epiphytes, as are Dendrobium, Oncidium, Vanda, Cattleya, and many many more. This term is used to describe plants that grow attached to other plants, trees, branches, stumps; in other words, epiphytes do not grow in soil. Rather, an epiphyte’s roots are exposed to the air (hence the term “aerial roots”) and cling to the surface of tree trunks and other organic matter while soaking up water and nutrients from the plant’s environment. These roots form the building blocks of the orchid and are absolutely vital to its ability to thrive.