To attach moss to wood or rock, tie thin pieces on with cotton thread or fine fishing line, or fix them with small dabs of cyanoacrylate gel, then keep the moss in firm, even contact until its rhizoids grow into the surface and hold it. Moss has no roots to plant, so you are simply holding it steady while it grips. Both methods work on driftwood and stone alike; the choice is between a temporary tie that rots away and a permanent bond that sets at once.
Prepare the moss and the surface
Rinse the moss and pull it apart into thin, loose pieces rather than working with one dense clump, because a thick wad rots dark in the middle while only its surface grows. Spread those pieces in a thin, even layer over the wood or rock so most of the moss touches the surface. A clean, slightly rough surface grips best; on very smooth stone the moss simply needs a little more holding until it catches. Keep everything damp as you work so the moss does not dry out.
The thread or fishing line method
Lay the moss over the wood or rock and wind cotton thread or fine, clear fishing line around it in a loose spiral, firm enough to hold the moss flat but not so tight it crushes the strands. Cotton is the usual choice because it rots away harmlessly over a few weeks, by which time the moss has grown its own grip and the thread is no longer needed. Fishing line lasts and stays slightly visible, so it suits a piece you may want to lift and rework. This is the gentler method and the one to use on delicate or expensive moss.
The superglue gel method
For a quick, permanent hold, dab small spots of cyanoacrylate gel, ordinary superglue in gel form, onto the wood or rock, press the base of the moss into each dab, and hold it a few seconds until it grabs. Use the gel rather than the runny liquid, keep it to the moss's base and off the green growth, and use it sparingly; a little turns white as it cures underwater but is inert and safe for fish and shrimp once set. Glue suits stone and hard, smooth wood where thread will not sit neatly, and it lets you place moss exactly where you want it with no waiting.
Aftercare while it takes hold
Whichever method you use, the moss is only resting on the surface until its rhizoids grow into it, which takes roughly three to six weeks. Keep it damp and undisturbed through that time, give it modest light and, in an aquarium, gentle flow, and resist pulling at it to check. Once the fine threads have caught, the moss holds on its own and any cotton thread will have gone. From there it spreads from its own fragments, so trimmings pressed onto fresh wood or rock will start the next patch.
Common questions
What is the best way to attach moss to driftwood?
Spread a thin layer of moss over the wood and wrap it on with cotton thread or fine fishing line, or fix it with small dabs of cyanoacrylate gel. Either way the moss must sit in firm, even contact so its rhizoids can catch and grow into the surface.
Does superglue harm moss or fish?
No. Cyanoacrylate gel, the same superglue used across the hobby, sets hard and inert underwater and is safe for moss, fish and shrimp once cured. Use it sparingly on the moss's base, keep it off the green growth, and press the piece down while it grabs.
How long does moss take to attach to wood or rock?
Give it a few weeks. New rhizoids grow into the surface over roughly three to six weeks, after which cotton thread will have rotted away and the moss holds on its own. Keep it damp and undisturbed in that time so the grip can establish.
For growing moss on garden stone rather than in a tank, see growing moss on rocks and stone, and for aquarium moss in general, aquarium mosses and propagating aquarium moss.