Can Orchids Grow Without Soil?

Tropical Orchids

• In the wild, tropical orchids are epiphytes, meaning they grow on hosts, such as trees. When grown in the home or garden, orchids need conditions that mimic their natural habitat. While many gardeners grow orchids in pots filled with fir tree bark or peat moss, a tropical orchid also can be attached to a tree or a piece of cork, a striking way to grow them without soil.

Creative Ideas

• Tropical orchids can be grown on inorganic materials such as plastic, but they require lots of watering to survive; the inorganic material doesn't absorb water. The Barkeria orcid is a smart choice if you want to experiment with this type of growing, and it's not without precedent. MIT student Dennis Szesko has grown Barkeria orchids on plastic to import them from abroad; the orchids -- not the soil -- are allowed into the United States. Because Barkeria orchids are accustomed to nightly rain followed by drying winds, they can survive without the constant moisture provided by organic soil mixes.

Terrestrial Orchids

• As with other flowers, terrestrial orchids, also known as hardy orchids, grow in regular soil. This gives them their name, as terrestrial refers to "in the ground," according to Dr. Leonard Perry of the University of Vermont Extension. Unlike tropical orchids, they cannot grow on hosts or in potting mixtures of tree bark, peat moss, perlite and other organic materials.

Expert Tips

• To attach a tropical orchid to a tree or piece of cork, Tim Anderson on the American Orchid Society recommends using cotton string to tie the orchid roots to the host. Over the course of approximately one year, the orchid roots will merge with the tree, while the cotton string harmlessly decomposes. If cotton string is not available, substitute wire or rope, which will have to loosen and ultimately be removed as the orchid roots grow and become firmly attached to the host.