Maidenhair ferns ( Adiantum raddianum) are a great choice for closed terrariums since they thrive in high humidity.
Maidenhair ferns ( Adiantum raddianum) are a great choice for closed terrariums since they thrive in high humidity. These delicate plants are difficult to grow indoors unless they are grown in a terrarium or greenhouse. Maidenhair ferns are relatively small ferns, but can still grow to be about one to two feet tall at maturity. For that reason, a medium to large terrarium is ideal. However, don’t be afraid to trim the fronds if the plant begins to outgrow the space.