Provide something to grow it on - Spanish moss will grow on just about any structure, including another tree or shrub, a fence or a building, trellis, arbor or patio overhang.
Situate the moss so that it gets part-shade. In full sun, Spanish moss may dry out too quickly and may even burn. If you grow Spanish moss in deep shade, it is likely to grow very slowly.
Generally, Spanish moss requires no watering, if you live in a humid, rainy climate, as it will draw the necessary water from the air and surrounding plants. If you live in a hot, dry climate, however, such as California or Arizona, or you are experiencing such weather, you will need to water Spanish moss every day or every other day. Not doing so can cause the moss to go dormant.
Give indoor Spanish moss bright light and moisture. It’s possible to grow Spanish moss indoors, as long as you mist it on a daily basis and put it under full-spectrum lighting or in a bright window.