Using ceramic pots was a cute way of cultivating bryophytes and may be a good way of making bryo gifts, but I found that the pots’ high rims make manipulations cumbersome. Because the rims are not transparent, they also cut out light, which bryophytes might otherwise use to grow, and they can cause shading under a dissection microscope. I have thus moved to using larger transparent containers: takeaway boxes. They are durable, they can be cleaned in a dishwasher between experiments, and they were available even during the Scottish lockdown.
Initially, I had trouble with fungal growth. I am not sure whether these fungi were a problem for the bryophytes or for me. They may just have been saprophytes (living on dead organic matter), but I did not like the look of them.
Originally, I used to compress the compost to flatten it so that I could better see the gemmae that I had “planted”. Individual lumps of compost are considerably larger than a M. polymorpha gemma, and I struggled to re-find gemmae in loose compost. I also kept my containers sealed to retain the moisture inside. But soon I found prolific fungal growth, which was less intense only in a few containers in which I had left the compost loose and uneven. It is not entirely satisfying to use lumpy compost, but I have now reduced the degree of compression that I apply. The other measure that really helped was that I added some vents to the containers’ lids. To stop dust and other unwanted things from dropping in, I covered these vents with plastic mesh, glued on with an electric glue gun. This level of ventilation is much better. The soil does not dry out over the course of a week, but the air inside the containers is much drier.
In a laboratory, one might want to grow bryophytes under axenic conditions, excluding other “contaminating” species from cultures. I am keen to try that out in the future. For now, I am enjoying the diversity of species that live in my containers, and I will write about them in the future.