Fittonia Column: A Tall Open Cylinder for Humidity Lovers

A narrow 18 cm cylinder is the hardest open shape to keep humid, and that makes it the right home for plants that collapse in dry air. Nerve plant and Selaginella both throw dramatic wilting tantrums at 40% humidity and both recover within hours of a misting, which turns a fragile-looking display into a forgiving one.

By The Terrarium DeskPublished 2026-09-08

Stratum by stratum

Perlite sump

2 cm of coarse perlite. In a narrow cylinder the drainage layer is nearly useless as storage, so use the lightest material you have — weight matters when you are lifting an 18 cm glass column to the sink.

Charcoal seam

0.6 cm charcoal. A narrow column has very little air exchange at the bottom, so this layer earns its place by keeping the sump from going sour.

Light seed mix

Five centimetres of coir-perlite seed mix, pressed only lightly. Both nerve plant and Selaginella root in the top two centimetres, so density below is wasted; what matters is that the surface stays open enough to absorb a misting.

Pellia cap

Press a live pellia thallus flat over the surface in one piece. Pellia tolerates the constantly damp surface of a narrow column better than any moss and knits into a continuous green skin within three weeks.

Vertical planting

Set creeping fig at the back wall — it will climb the glass — and nerve plant at the front, then thread Selaginella through the middle. Water down the wall with a pipette for the first month rather than misting the foliage.

Growing on

Nerve plant is the reason this build exists and is also its drama: it will flatten completely at 40% humidity and be upright again two hours after a misting, with no lasting damage. Selaginella is slightly less forgiving and needs the surface never to dry fully. Creeping fig is the tough one and will grip the glass within a season, which means you should decide now whether you want it climbing or kept as a low mound. Push its tendrils back onto the surface every few weeks if you want the mound form.

Upkeep rhythm

Mist the inside walls daily in winter and every second day in summer — the column loses humidity fast through its open top. Water down the glass wall with a syringe when pellia looks dull rather than glossy. Because there is no lid, expect to top up the water every three or four days, and never let the level sit above the charcoal seam. Trim creeping fig tendrils monthly to keep the column readable from the front.