The button fern, Pellaea rotundifolia, is a common specimen among house plants and is a fern that is also displayed in many offices. It gets its name from the small, round shape of the branching portions of its leaves. The plant is considered to be of moderate difficulty to grow if starting one from spores, as ferns do not produce seed, but it is easy to maintain once it is established. Ferns, as a general rule, are somewhat primitive plants that do not flower, so they do not require a lot of care to flourish, though the button fern is native to tropical regions, so warm, moist conditions suit it best. One of the advantage of growing a button fern over that of other ferns is that the plant tends to stay manageably small and a 6 to 8 inch (15 to 20 centimeter) pot is as large of a container as it will need to reach full adult size.
A full-sized button fern will have up to 12 fronds extending from a central base, and, as it ages, the button-shaped leaves hanging off of each frond will take on an oval shape. Stems that become damaged or die back can be trimmed off without harming the plant, and, as the button fern gets older, it is easy to notice as the stems turn a dark red in color. Among the various types of ferns that are cultivated as ornamental plants, the button fern requires less watering and misting of foliage than most. The best way to tell if the plant is receiving the right amount of moisture for the environment in which it is growing is if the edges of the fronds are green and vibrant, which indicates that the plant is healthy.
When growing button ferns, it is helpful to remember that they are often called the Cliff Brake fern, as they tend to propagate in the cracks and edges of a limestone base along tropical cliffs or steep inclines in New Zealand, from where they originate. This means that they thrive in bright though indirect sunlight where they get plenty of water, but are also subject to periods of drying out. The best average temperature for the species is between 65° to 75° Fahrenheit (18° to 24° Celsius) during the day, and 10 degrees below that range at night. High humidity is also natural to their native environment, so they tend to thrive in bathroom settings where they can serve as hanging plants close to the light source.
Soil that is continually wet and soggy will harm the button fern, so it needs to be watered about once every week and allowed to dry out moderately in between then. If the plant is being over-watered, the foliage will begin to turn yellow and wilt. If the plant begins to become crowded in its container, a portion of it can be removed and potted elsewhere as the fern tends to become root-bound in its container over time. The fern also enjoys full sun if available, and is prone to being attacked by common pests like mealy bugs and aphids, especially in shaded conditions.