I have done some experiments with the use of the felt in containers outdoors to see how the moss species used would fare. In two cases of using Bryum species what I have learned is that the felt system is effective when the felt is enclosed in a plastic case such as that used for holding fresh fruit, like grapes, found at your local grocers. With felt sitting in a tray without being inside any enclosed case the moss just has not done as well. So my conclusion would be that humidity and protection against spatter are necessary for the felt system to work when used in a growing tray.
I am also trying to rescue some moss that was barely hanging on and have placed the surviving pieces into a "Humidity Case". The pieces are slowly recovering and growing upon the felt.
The top image is when the moss pieces were place into the HC on June 8, 2010. The bottom the status as of July 8, 2010.
