Most ferns develop shallow root systems. To maintain the proper balance of root systems and space, some ferns, depending on growth rate, need repotting several times a year. For others, repotting at least once a year is preferred. 

Ferns rarely suffer from pests and diseases. But one common problem is mildew, which can be seen on the leaves of the plant. It can be treated by trimming all mildew parts or with a fungus spray. Root rot is another problem that is a direct result of over watering. To avoid this make sure that there is proper drainage. Remove dead fronds or dropped leaflets regularly to maintain its health. 

 

Some variety of ferns outgrow their pots and they have to be divided or discarded. When it comes to dividing, remove the plant from the pot and use a sharp, long-bladed knife to halve or quarter the root ball. Then spread the roots in the new soil. The main requirements after dividing are to water the roots and new soil thoroughly and to provide a humid atmosphere by misting the first few weeks.