Live Welsh Sphagnum Moss For Inverts

The water-holding in sphagnum is done by cells that are already dead. Every leaf is a mesh of small green living cells wrapped around much larger empty ones, called hyaline cells, which are perforated to the outside and do nothing but fill. That structure is why a handful of bog moss holds something in the order of sixteen to twenty-six times its own dry weight in water, and why it goes on releasing it slowly instead of all at once. There are around 380 species worldwide and thirty-odd recorded in Britain.

The same chemistry that makes it useful in an enclosure made it useful in a field hospital. Sphagnum acidifies its surroundings by taking up calcium and magnesium and releasing hydrogen ions in exchange, and compounds in its cell walls slow decomposition down. Dressings made from cleaned sphagnum were gathered across Britain, Canada and the United States during the First World War, on the strength of a case made by an Edinburgh surgeon and a botanist in 1914, and the moss went into wounds because it absorbed heavily and resisted spoiling. In a tub it does the smaller version of the same job.

This is living moss, picked by hand in Wales, not the dried compressed kind. It arrives springy and damp. Use it for humidity pockets and moist hides, as a laying medium, in springtail cultures, as cover for tarantulas and scorpions, and anywhere you want a corner to stay wetter than the rest without soaking the substrate.

Why it may not arrive green

Sphagnum comes in far more colours than green. British bog mosses run from red, pink and orange through many shades of green to almost white, and the colour of any patch depends on the species, the shade, how wet the moss is and the time of year. Colours are usually at their richest in late summer and autumn, when reds deepen and yellows turn orange, so a freshly picked batch can arrive mostly pink, peach or pale yellow, or all three in one bag. We cannot choose the colour you receive, so please order expecting any of those shades. Colour on its own is not a sign that the moss is old or dying.

The pink and red come from sphagnorubin, a pigment bound into the cell walls. The moss makes it to shade itself from strong light, and makes more when that light comes with nights below about 5°C, drying out or an imbalance of nutrients. That is why moss in the open colours up as the nights turn cold, while moss under heather or trees can stay almost completely green, even in species that are normally red. The yellows and ochres are partly the species, since some, Sphagnum papillosum among them, are naturally ochre to golden-brown, and partly the same sun: moss from an exposed patch is often duller and more ochre than the same species in shelter. It is also common for one species to grow mixed into a patch of another, so a single clump can show several colours.

None of this changes what the moss does in a tub. The pigment sits in the cell walls and the water in the empty hyaline cells, so a pink or yellow handful holds water just as a green one does. Moss that has dried a little looks paler, as those cells fill with air; soak it and the colour returns quickly. Kept alive at room temperature and out of strong sun, its new growth tends to come through greener, but the pink already in the leaves will not rinse out, because the pigment does not dissolve in water.

Treat it before it goes in

Moss picked outdoors comes with residents. Mites are the usual passengers, and there can be plenty of them. Rinsing under cool dechlorinated water while teasing the strands apart, then holding it in a clear sealed tub for a week or two and picking off whatever surfaces, will keep the moss alive and deals with most of it. If you need certainty rather than most, kill it. A domestic freezer runs at about -18°C and the tissue-lethal threshold for sphagnum sits near -16°C, so two or three days in there will almost certainly finish the plant along with the passengers. Heat is the same story from the other direction: half of it dies at around 50°C, so boiling water over it, or a damp minute in the microwave taken in short bursts and not in one go, sterilises thoroughly and leaves you with material that is still perfectly good for moisture and cover. For an isolated culture or anything delicate, take the certainty. For an established bioactive setup, a rinse and a quarantine is usually enough.

Keep what you do not use in a loosely closed bag in the fridge, where it will stay in condition far longer than it will on a shelf. If you want moss purely for water retention and have no interest in keeping it alive, the dried sphagnum is less work and stores indefinitely. Our guide to sphagnum moss for isopods covers what it does in an enclosure and whether they eat it, and for culture setup our article on long-term springtail cultures covers where moss helps and where it does not.