How to Propagate Indoor Ferns
Creating the best possible conditions
A certain amount of basic knowledge is applicable to all methods of fern propagation.
The best time: Ferns can be propagated all year round but the ideal time is in the spring as the young plants then benefit from the higher intensity of light and do not have to endure the atmosphere of dry, centrally-heated air.
Compost: Seeding compost is suitable.
• Carefully water the young seedlings and keep them evenly moist (not wet).
• Stand the pots in a warm position with air and compost temperatures of 20-25° C (68-77° F).
• The position should be bright but protected from direct sunlight.
• To ensure high humidity, bend rust-proof wire into an arch and push the ends into the pot. Draw a transparent plastic bag over this and tie it up. If there is a great deal of condensation, take the bag off for a few hours now and again.
• As soon as new fronds have formed, the little plant can be gradually hardened off. This is done by removing the plastic bag for periods of time and then entirely.
• This is the time when very low doses of fertilizer can be given.
Method. Remove the plant you want to divide from its pot and cut through the rootstock with a sharp knife so that two or more individual parts with a vigorous vegetation point and sufficient roots are created. The vegetation point represents the heart of each plant, from which new fronds will grow. Without it the newly divided fern would not be viable. Dead roots and leaves should be removed and the separate pieces planted in individual pots.
• In the case of rhizomes that grow above ground, for example those of Davallia, suitable places for dividing are easy to recognize.
• In the case of underground rhizomes, you will be able to recognize sections suitable for cutting off by the development of a group of new fronds on the compost surface.
• Use a sharp knife to cut the rhizome into individual sections, each of which should have several bulbils. The bulbils are recognizable as the places from which fronds emerge or as slight swellings. It is best if these rhizome parts have already produced roots as unrooted rhizome sections will not grow very well.
• The sections of rhizome that grew underground should be covered with compost to the same depth as before.
• The parts of rhizomes that grew above ground should be laid on the compost and pinned down with a rust-proof wire clamp.
• Further care: see Care above.
Propagating from shoots
Shoots from horizontal axils are developed mainly by Nephrolepis. Once they come into contact with the , they grow roots and form new plants from their bulbils. This development can be encouraged by placing a pot of compost beside a Nephrolepis and then fixing shoots to its surface with clamps. After a while, the bulbils will produce new shoots. As soon as several fronds have developed, you can separate the young plants from the mother plant.
• Further care: see Care above.
Vegetative propagation through offset plantlets occurs relatively widely in ferns. New, small plantlets form the mother plant from the bulbils grow in various places on the fronds. Once they come into contact with the soil, they start producing roots.
• In the case of Adiantum caudatum, they sit on the tips of the fronds that then hang down to touch the ground.
• Inspecies, they form all over the frond in such large numbers that the fronds are forced downwards and the plantlets thus make contact with the soil.
• Inpedata and Hemionitis arifolia they develop at the base of the leaf stalk .
Method: By bending the frond downwards and pinning it to the compost with a wire, you will enable the offset to form roots while still attached to the mother plant. Make sure the humidity is high. Once you can see roots, you can separate the plantlet from the parent and plant it in a pot.
Alternative: If you wish, you can cut off entire parts of fronds together with offset plantlets and lay them on compost. Once the plantlets have taken root, they can be planted in individual pots.
Of the few ferns that produce tubers, the best known is Nephrolepis cordifolia. The tubers develop on the underground rhizomes. If they are separated, together with part of the rhizome, and repotted, entire new plants will grow from them.