Ecosphere Vessel notes for closed and open terrariums 中文

Closed · 20 cm · 90 days to establish

Culture Jar: A Slow-Growing Aquascape in Dry Air

This build takes four species normally grown submerged in an aquarium and grows them emersed, on a wet sand floor inside a sealed jar. It is the slowest build in the collection — 90 days before it looks like anything — and the only one where the substrate is deliberately saturated rather than merely damp. The reward is growth forms you simply cannot get on a moss wall.

By The Terrarium Desk

Culture Jar: A Slow-Growing Aquascape in Dry Air — cross-section plate
Cross-section plate · apothecary form · glass highlight and stratum bands drawn parametrically from the measured build

Stratum by stratum

  • Drainage: none — this is a submerged-style culture
  • Filter: 1 cm charcoal under a fine mesh
  • Substrate: 5 cm akadama fines topped with 1 cm sand
  • Cap: none — plants are set directly into the sand
Container form
Closedapothecary
Settled height
20 cm
Working volume
2 L
Light demand
Low
Humidity band
Sealed loop
Difficulty
Advanced
Days to establish
90 days

Stratum by stratum

  1. No drainage layer, by design

    Every other build in this collection has a gravel sump. This one does not. The culture is kept at capillary saturation, so a drainage reservoir would be permanently full and contribute nothing but a stagnant layer.

  2. Charcoal under mesh

    1 cm charcoal covered by a 1 mm mesh screen. The mesh is the trick: it lets water and dissolved gas move while preventing the akadama fines from silting into the charcoal and sealing it off.

  3. Akadama fines and sand cap

    Five centimetres of akadama fines, then 1 cm of fine sand levelled flat. Akadama holds water and releases it to the sand cap by capillary action, which gives you a consistently moist surface with no standing water.

  4. Emersed planting

    Set Bucephalandra and Christmas moss with aquascaping tweezers, rhizome just above the sand. Angle the tweezers as you withdraw so the sand closes behind the roots. Never bury a rhizome; it rots within days.

  5. Saturate and seal

    Use a 30 ml syringe to wet the sand from below through a corner until the surface glistens but no water pools. Seal the band and place the jar in low light — this is a low-light build and anything brighter grows algae on the glass within a week.

  6. The 90-day patience test

    Growth is measured in millimetres per month for the first two months. Do not fertilise, do not open, and do not judge. From day 60 the Riccardia begins to spread and the jar starts to look intentional.

Growing on

Bucephalandra is the centrepiece and the slowest plant here — one new leaf a month is normal and healthy. Christmas moss grown emersed produces a tighter, more triangular frond than its submerged form, which is the reason to do this at all. Riccardia chamedryfolia is the spreader and will knit across the sand surface if the humidity stays constant; a single dry week sets it back by a month. Taxiphyllum tolerates the widest range and can be used to fill gaps while the slower species establish.

Upkeep rhythm

Almost nothing for the first two months. From day 60, check monthly that the sand surface still glistens; if it has gone matte, inject 10-20 ml of rainwater at a corner. Never use tap water — the dissolved minerals accumulate with no drainage layer to flush them out, and after a year the sand will crust over. If algae appears on the glass, reduce light rather than adding a cleanup crew; springtails do not survive on a saturated substrate.