Propagating Indoor Ferns

A safe nursery for young ferns

How do you propagate plants that do not produce flowers or seed? Ferns solve this problem for themselves by forming spores. When these germinate, a gametophyte is produced and from this a prothallium then grows to produce male and female cells called gametes.

When the male and female cells mature, the male sperm fertilizes a female ovum and a new fern plant begins to grow.



Propagation from the distribution of spores

By spreading spores yourself you can reproduce the natural propagation process and then observe the unique events of fern multiplication. It is, however, a difficult undertaking and not always crowned with success. For this reason very few nurseries specialize in fern propagation. The determined amateur gardener should try out this technique initially with one of the species that does not present too many difficulties, for example Cyrtomium or Pteris.

Spores: Spores can rarely be bought in the trade like seed. You may be lucky enough to have a growing fern that bears spores, otherwise you will have to obtain a frond with spore capsules from a friend or acquaintance. Some ferns produce spores almost all year round, others only under optimum conditions.

With most species you will need a lot of experience to determine exactly when the spores are ripe.

Unripe spores are useless for sowing. On the other hand, completely ripe spores are catapulted out of their cases and, because of their miniscule size and low weight, will be broadcast far and wide by the slightest movement of air.

Collecting the spores must, therefore, be done shortly before this happens.

My tip: Very often the spore capsules are white or light green in colour in their unripe state and turn brown at the point of maturity. In certain other species the mature spores are coloured grey, yellow or orange.


Harvesting spores

• Cut off a fern frond when the spores are ripe and wrap it in paper.

• Hang it up in a dry place for at least three days. When the ripe spores are catapulted out, they will be caught in the paper.

• Next, carefully remove any rotten or deformed spores.

• It is best to plant them right away. The ability of fern spores to germinate may endure for only a few hours or for decades, depending on the species. If you do not want to sow them immediately, you should store the spores in a cool, dry place to prolong their ability to germinate.

How to sow: Place nutrient-poor compost (for example, seeding compost) in pots or small dishes. The best plan is to use new containers or else carefully clean used ones beforehand. Pour boiling water over the compost and allow the excess water to run away. This treatment ensures that any undesirable spores of algae, fungi and mosses are killed off. Once the compost is just lukewarm, sow the spores sparsely and use a fine mister to spray them with cooled, boiled water. Do not cover them with compost.

Care: The sown spores will require warmth (20-25° C/68-77° F) without direct sunlight. On no account should they be allowed to dry out. Spores sown in plastic containers should be covered with a pane of glass or clingfilm. After about four to six weeks, little prothalli should develop from the spores. Fertilization, which occurs on the undersides of the prothalli, will only succeed if a film of moisture is present. The first new leaves of the young fern plants will form from the fertilized ova (depending on the species) three to eighteen months after sowing. From now on, you should remove the cover occasionally to harden off the young plants. As soon as they are large enough to touch each other, they should be pricked out separately. Once they are 5-10 cm (2-4 in) tall, the young plants can be planted singly or in small groups in little pots.

Hemionitis arifolia wiht a new plantlet emerging from a bulbil


Tissue culture

Years ago, only sterile ferns could be propagated from rhizomes. Nowadays, using tissue culture, small sections of tissue can be used to generate a large number of whole, identical plants. Specially installed equipment in laboratories is required for this method of cultivation. This process ensures that plant lovers have access to ferns of the highest quality at reasonable prices. Today many varieties of Nephrolepis, Platycerium, Pellaea and Davallia are grown in this way.

It is really not practical for amateurs to propagate ferns by this method as totally sterile conditions must be available. Unless your hobby is actually biology rather than gardening, it is probably best to leave this sort of thing to the experts and simply buy the ferns you want to grow.

01. June 2011 by Dave Pinkney
Categories: House Plants, Indoor Ferns | Tags: , | Comments Off on Propagating Indoor Ferns


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