Moss is the ideal potting media surface in traditional outdoor bonsai wherever it is possible to grow it. Generally moss needs a relatively high humidity so it's difficult or impossible to grow it in most places.
CAN IT GROW INDOORS?
As we lead research on Tropical & True Indoor Bonsai, we seek to learn, to share, and to teach techniques that can raise the standards to the highest levels.
At Fuku-Bonsai in Kurtistown on the Big Island of Hawaii, our natural climate is ideal for growing moss to the point that we have developed methods to clean it off the plants from time to time. Various mosses grow on trees, rocks and even on paved shaded roads.
So while we have a lot of options here, there's need for more information to provide options for others in various environments and I invite any and all interested parties to contact me with ideas to help everyone!
These two photos show our first experiment as we have never previously tried to grow moss indoors. This effort was based upon the first reported customer success using a 10" full globe goldfish type bowl with a circular top opening with one of our lava plantings inside on 2" of gravel. The gravel was kept damp with the top of the gravel dry with the rock sitting on dry gravel and soak saturated weekly.
In our first photoed trial, a 3.5" diameter x 10" tall glass cylinder was filled with 6" of coarse bottom gravel with water in the bottom 3". A piece of rock with Java Moss growing on it has been on the gravel for over a month and is flourishing!
JAVA MOSS TRIALS
Which is the ideal moss for indoors (or to use outdoors when night temperatures are above 55 degrees F.)? Our initial trials are of Java Moss which has been the most successful to date. Java Moss is most often used in aquariums where it attaches to driftwood, rocks, and tank walls. Then over time it begins climbing out of the tank, down the walls and onto the ground if damp enough. It will grow on an old concrete slab --- even in full tropical sun during the rainy seasons although it will become more like small ferns and turn yellow. Strange but tough and might grow indoors if given enough humidity.
The first trial indicates that Java Moss will survive in a "open terrarium" or "semi-terrarium environment. Imagine a rectangle tank similar to an all-glass aquarium but one that is as wide as the display surface with glass sides that are about 6" tall. If that waterproof tank was filled with 2" to 3" of coarse bottom, river rock, or other material such as the plastic "egg-crating" grid used in ceilings below fluorescent tubes, the bonsai container would not be sitting on a wet surface (which may cause root rot) but would benefit from the increased humidity.
In the nursery, it was found that Java Moss will grow under 85% shade cloth in flats with our standard media. It will form an airy sheet or mat that will sit on the surface and can be easily peeled off. It can be pressed around the trunks of the trees and if it becomes established, will begin to spread in an attractive manner.
Experiments are already being done in dry climates with promising results. If it is possible to increase the humidity and light levels (either with sky-lights or supplemental artificial lights) it would be possible to create a relatively economical "optimum plant room." Because Dwarf Schefflera does not have a high light requirement, it may be possible to create a relatively economical "True Indoor Bonsai Plant Room" with just a single metal halide light on a track on the ceiling that would light the entire room sufficiently.
"HUMIDITY TANK" QUESTIONS THAT NEED ANSWERING:
How high should the side walls be? How deep must the gravel be? How much distance is needed between the "water-line" and the gravel surface for the surface to allow sitting bonsai on it without causing root rot?
OTHER TRIALS TO DATE
Recently I sent samples of various mosses to our contributing editors Ryan Chang (Waipahu, Hawaii) and Jay Boryczko (Farmington Hills, Michigan). Ryan was totally unsuccessful.
Jay has begun some trials and commented that the Fuku-Bonsai Cornstarch Keto-Tsuchi grabs it easily.
This report will be continued in the next Journal. Email firstname.lastname@example.org if interested in making input and participating in this project. ~~~David