Cushion moss against sheet moss: which one took in sealed glass
All the moss in my jars comes from within fifty metres of the back door: a tight cushion moss that grows in rounded mounds on the top of the garden wall, a flat sheet moss from the brick path on the shaded side of the house, and a feathery, upright moss from a rotting log at the bottom of the garden. I took a palm-sized piece of each, rinsed them under the tap to shift the woodlice and grit, and set them into three identical jars on the 2nd of July, with the same substrate and the same 20 millilitres of rainwater.
Five weeks later the differences are obvious even from across the room. The cushion moss has knitted into its mound, kept its colour, and has small pale new growth at the tips. It beads with condensation every afternoon and seems to like it. The sheet moss has done almost nothing. It is alive, in that it is green and not slimy, but it has lifted slightly at the edges and gone a flat, dark shade that I associate with moss on a wet pavement in November. I suspect it wants more air movement than a sealed jar can offer, and I have seen the same in a friend’s jar.
The log moss is the interesting one. It grew fastest of the three in the first fortnight, standing up tall and bright, and then I noticed a slug the length of a grain of rice on the glass, two small white mites, and a fungus gnat that must have come in as a larva. The slug was removed with tweezers and I let the rest be. The moss has since settled down and is doing well, but there is a lesson there about rinsing more carefully, or quarantining material from rotting wood in an open container for a week before sealing it in.
For future jars, cushion moss is the default and goes on the high ground, where it can form a mound and still catch the light. Sheet moss I will try again only in a jar with a loose lid. The log moss gets a week in a shoebox first, and anything that walks out of it gets returned to the log.