Wednesday 21 December 2022

Growing Asplenium prionitis indoors

Asplenium prionitis

Asplenium prionitis

The specie name prionitis means like a saw, this fern has toothed pinna margins.


On ground or boulders along streams or river courses, deep shade in wet coastal forests.

Distribution in South Africa

Eastern Cape and KwaZulu-Natal

Distribution worldwide

Africa, Madagascar, Comoro and Mascarene Islands.


I have established that Asplenium prionitis makes a great very easy to grow houseplant, growing well indoors under relatively high light conditions but they do not tolerate full sun conditions for long without burning.

My plants originate for a small plant that I collected in the forest on the eastern side of the Wentworth hospital in Durban about 40 years ago.

Asplenium prionitis appear to grow in any well drained growing medium that has a high organic component. My plants are presently growing well in a mixture of coco fiber chips with a little added charcoal.


I water heavily about once per week to flush out the growing medium and mist daily using an insecticide sprayer.

The sprayer I use to water and feed my plants


I feed frequently using a very dilute amount of a variety of plant feeds such as

EasyGro™ Flower and Fruit

is a 3:1:6(46) water soluble fertilizer, high in concentrations of Potassium ideally suitable for crops during the flowering and fruiting stages.

SEAGRO™ Bio-Fertiliser

Bionutrient with Enhanced Amino Acids. A fish emulsion rich in micro & macro elements and 17 amino acids. Seagro is used as organic fertilizer in agricultural practices for maintenance of crop health. Seagro has a remarkable impact on crop quality as well as yield through the activation of key metabolic processes. Seagro serves not only as a nutrition and stress reliever, but also plays an important role in the vitality of the microbial population in the soil.

Nitrosol Original Biological Fertiliser

is the original formulation developed by Dr. Peter Kauzal, a veterinary surgeon, from ruminant blood and bone. Nitrosol Original has a balanced NPK of 11.5.7 plus trace elements and minerals and recommended for use in all horticultural crops and home garden.

Fulvic acid.

Fulvic acid is group of chemicals formed when plants and animals break down. It is found in the humus (organic matter) part of soil and peat, and is also found in streams and lakes.

Fulvic acid benefits of increases root respiration and formation,enhance plant growth and yield. Humic fulvic acid can enhances pH buffering capacity, enhances photosynthesis and respiration, increases cationic exchange.

Brings about an improvement in the transport of nutrients, making them available in the areas of need. Increases the synthesis of proteins and nucleic acids, which will facilitate the action of enzymes formed with some amino acids and micro-nutrients.


I also feed and mist regularly with a week solution of both black tea and rooibos tea which appears to be very beneficial to both my ferns as well as my orchid plants.


Asplenium prionitis propagates very easily from spores if one has the patience to wait a few years for a good sized mature plant, the plus factor is that one can easily propagate large numbers of new plants.

The sporangium containing the spore can be clearly seen under the leaves

The method that I use is to obtain a large glass jar into which a place a layer of small crushed stone topped with a thin layer of silica sand used for swimming pool filters. Over this layer I place a thin layer of peat or coco peat that is salt free onto which I sprinkle the ripe spore. To water I use a small insecticide spray bottle watering enough that the water creates a small reservoir of water approximately half way up the crushed stone. I then cover the jar with a piece of cling wrap that can be fastened by an elastic band of piece of string and place the jar in an area of bright light that does not receive and direct sunlight or under lights giving around 5,000 lux for between 12 -14 hours.

Asplenium prionitis seedlings growing in the jar they were planted in

When large enough I pot the seedlings into small pots and place in a very humid place usually over a tray of water.

Asplenium prionitis seedling that was planted out six months ago

Pest control

To date I have not encountered pests on my plants however I treat them on a regular basis As I do with my other indoor plants as a precaution because other Asplenium species that I grow are prone to soft scale and mealie bug attack. In the past I sprayed my plants which entailed the use of spray overalls, googles and respirator which was a major task and was both hazardous to my health as well as made the entire house stink for a day or two. Furthermore, this process needed to be repeated on a regular basis. I now use a granular Insecticide with great success and no fuss at all. The product that I use is , Efekto Granules Plus active ingredient Imidacloprid (chloro-nicotinyl) which I apply to the roots and is taken up by the roots and evenly distributed to the entire plant which is highly effective against most sucking insects and provides long term control between 4 – 8 weeks. Efekto Granules Plus is a Neonicotinoid a class of neuro-active insecticides chemically similar to nicotine compared to organophosphate and carbamate insecticides, neonicotinoids are less toxic to birds and mammals, and therefore very safe to use within the home environment.

However, Neonicotinoid has a very bad name for very good reasons for widespread agricultural use, for reasons that do not apply at all for very limited indoor use, in fact it is an ideal insecticide for indoor application due to its low toxicity for humans and its very targeted use in comparison to sprayed insecticides.. Neonicotinoids have been studied in relation to adverse ecological effects, including honey-bee colony collapse disorder (CCD), and declining populations of insect-eating birds. In 2013, the European Union and some neighbouring countries restricted the use of certain neonicotinoids. In 2018 the EU banned the three main neonicotinoids (clothianidin, imidacloprid and thiamethoxam) for all outdoor uses, but in 2020, France re-allowed the use of neonicotinoids on sugar beet crops. Several US states have restricted neonicotinoids out of concern for pollinators and bees.

Article written by Michael Hickman 21.12.2022

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