Boston fern root nodules: what are the balls on the roots of fern plants?

Ferns are ancient plants that reproduce by producing and spreading spores, just like fungi and mosses. The Boston fern, also known as the sword fern, is a reliable plant with long, graceful masses of fronds. You can also see root nodules in Boston fern plants.

Boston fern root nodules

Very popular as a houseplant, the Boston fern grows in pots or hanging baskets. In hot climates where temperatures are constantly above 50 F. (10 C.), the fern grows easily outdoors.
If you repot or transplant a mature Boston fern, you may notice balls on the fern’s roots. These balls, which develop where the fronds meet the underground rhizomes, are small, round, grape-sized growth nodules. The nodules, also called «bulbs», usually appear towards the end of the growing season, between late summer and autumn.

Are Boston fern root balls harmful?

Boston fern root nodules are not harmful. It is a natural adaptation that ensures the plant’s survival. Boston fern root nodules help the plant absorb moisture and nutrients from the soil. They are important because they store water for the plant during drought periods.

Propagation of Boston fern nodules

Boston fern is often spread by dividing a mature plant or by planting small seedlings that grow in the middle of larger fronds. You can also spread the plant by planting the nodes of the root. Plant a small section of rhizome with root nodules attached in a pot filled with wet soil or equal parts sand and peat. A rhizome with at least three nodules is more likely to take root.
Sometimes an old dead fern can be successfully reproduced by planting nodules, which can be fleshy and green even if the main plant is dry and withered. Plant the nodules in a pot with the green side up, just above the surface of the sterile mixture.
Place the pot in a plastic bag and fill the bag with air. Place the jar under indirect light and at a temperature of 15-20 C (59-68 F).
Hopefully, you will notice small white nodules within one to three months. When the nodules develop roots, remove the plastic bag and plant each rooted nodule in its own pot. Moisten the potting soil and place each pot in a plastic bag to create a greenhouse environment.
Allow the new fern to mature, then remove the bag and plant it in a larger pot or garden.