Sphagnum Moss Potting Technique by Roger Snipes
Brian Batchelder developed the technique of potting bonsai in pure sphagnum moss sometime in the 1980’s. With this method all the normal potting soil is replaced with pure sphagnum moss. While this technique can be used on virtually all trees, I have found that it is especially suitable for potting tropical and semi-tropical trees that must spend part of their time indoors. I find that it is easier to control watering when these trees are potted in sphagnum, and it is possible to keep moss growing on the surface of the sphagnum while the trees are indoors; something that is difficult to do when trees are potted in normal bonsai soil.
The sphagnum method is also valuable when using small pots, such as with mame and small accent plants. The small soil volume of these plantings normally means that they dry out very quickly between waterings, however when they are potted in sphagnum I find that they can go longer between waterings without drying out. (However, they can still need more frequent watering than plantings with a larger soil volume.) The method is not as suitable for very large trees since one must be able to pick up the bonsai and submerge the rootball during watering.
Instructions for Potting with Sphagnum Moss
- Select an appropriate quantity of long fiber sphagnum moss and remove any grass, weeds, or other extraneous material. Put the sphagnum in a bucket of water to soak while the tree is prepared. Select an appropriate bonsai pot for the tree. If you are doing any major pruning and wiring on the tree this should be done before potting.
- Remove the tree from its container and clean all the soil off the rootball. This is best done using a combination of teasing the roots out with a chopstick or root hook, and washing the remaining soil off with a stream of water. All of the soil must be removed from the roots.
- Trim the roots as necessary to allow the tree to fit properly into the bonsai pot.
- Once the roots are cleaned of soil and trimmed place a layer of wet sphagnum in the bottom of the bonsai pot. Work wet sphagnum into and around the roots of the tree and position the tree in the pot.
- With the tree positioned in the pot continue to pack wet sphagnum around the roots, working it in with your fingers. The sphagnum should be tightly packed in and around the roots. If the sphagnum has been properly packed around the roots you will be able to pop the tree out of the pot and the roots and sphagnum will hold the shape of the pot.
- To give the composition a more finished look you can press collected moss (with all soil removed) onto the surface of the sphagnum, or you may leave it as is and wait for moss to start growing naturally on the surface.
