Riccia

MossyMystic

Has anyone used Riccia (Riccia fluitans) as a living wick/top-dressing for indoor plants?

I accidentally got a tuft of Riccia with some aquarium trimmings and pressed it onto the damp rim of a self-watering planter with LECA. It anchored to the clay in a week and formed a springy, bright green mat. Unexpected side effects:

The LECA surface stays evenly moist but not soggy, and fertilizer crusting stopped.
Fungus gnat activity dropped around that pot.
Midday it actually “pearls” emersed under lights, and there’s a faint cool, humid microbubble right above the surface.
The aroid in that pot pushed new feeder roots into the top layer.

Now I’m wondering if we’ve been sleeping on Riccia as a living humidity buffer/biowick indoors. Questions for anyone who’s tried similar:

Longevity emersed: Can Riccia run long-term on capillary moisture without a lid, or does it inevitably melt unless RH stays >60-70%? What PPFD/photoperiod keeps it compact instead of fluffy?
Nutrients and EC: Does it compete meaningfully with the plant for nitrogen, or act like a micro biofilter that evens out salts? Any EC/TDS or hardness ranges where it sulks emersed?
Gnat pressure: Does the dense mat block emergence and egg-laying for you, or does the constantly damp surface make gnats worse?
Airflow and cleanliness: Tips to avoid cyanobacteria/algae films on the mat? Gentle fan vs intermittent misting? Are brief H2O2/alum dips safe for Riccia if contamination appears?
Pairings: Good companions? I’m thinking jewel orchids, anthurium seedlings, peperomia, carnivorous plant trays. Bad pairings where it outcompetes moss or stays too wet?
Mounting tricks: Best way to keep it flat and tidy-hairnet/mesh, thread on lava rock, ceramic wick strips, or pressed into LECA? How often do you trim to prevent it from lifting off?
Sanitation: If sourced from aquaria, how do you clean it to avoid sneaking in snails/hydra/planaria before introducing to housepots or terrariums?
Bonus: Has anyone measured a temperature or RH bump above a Riccia mat, or seen improved root health from the oxygenated, moist interface?

My current setup: 12h at ₁₀₀ PPFD, gentle airflow, 55-65% RH, 22-24°C, semi-hydro with 250 µS/cm tap plus ₅₀ ppm N weekly. Two weeks in, the mat is 5-7 mm thick and stable.

If a few folks are game, I’d love to compare a simple A/B: same plant and potting, with and without a Riccia cap, and track moisture, gnats, and growth over a month. Anyone up for it-or already tried this?

theterrariumtrove

Whoa, this is such a cool accidental discovery-Riccia as a living topper? I’ve dabbled with it in paludariums, but never straight on LECA like that. Super intriguing for humidity buffering!

On longevity emersed: In my setup (around 70% RH, 12h/150 PPFD), it held compact for 3 months on just capillary from a wick, but started thinning below 60% RH without occasional misting. Keeps it denser with lower light-try dialing to 80 PPFD to avoid fluff.

Gnat-wise: The mat totally blocked egg-laying for me on a few pots; no adults emerging after a week. But yeah, keep airflow gentle to avoid stagnation-I’ve used a small fan on low, no algae issues yet.

Pairing tip: Works great with Peperomia obtusifolia; the roots love the moist interface without sogginess. Avoid with sphagnum moss though-it outcompetes and dries it out.

Sanitation hack: I quarantine in dechlorinated water with a dash of hydrogen peroxide (1:1000) for 24h, then rinse-zaps snails/hydra without harming the Riccia.

I’m totally in for that A/B test! Got a spare Anthurium crystallinum to trial-let’s swap notes in a month. Who’s else jumping on this?