Terrariums are billed as the ultimate no-maintenance houseplant setup, so it’s not surprising that many newbie terrarium owners are a little miffed when, a few months in, things start going wrong.
Happy, well-maintained terrariums bask in the sunlight in a shop window. The glass of a closed terrarium should go through a daily cycle of misting up and clearing: this is totally normal, even if the terrariums you ogle on Instagram always have crystal clear glass.
The Glass Is Constantly Misty
Photograph by Al Hartley courtesy of London Terrariums.
If your glass is green, it’s a sign that algae has started setting up home. You may be able to wipe away the streaks with a cloth dampened with lemon juice or vinegar (keep this well away from your plants).
Photograph by Jess Groves via Flickr.
The Glass is Dirty
Photograph by Jess Groves via Flickr..
Room to grow, in an open terrarium. Chlorophytum comosum and Bartramia pomiformis keep company with sphagnum and a tiny fern.
The Plants Are Overgrown
Terrarium in progress.
The Plants Are Leaning to One Side
Photograph by Amy Gizienski via Flickr.
Mold or Fungus Is Growing
Photograph by Al Hartley courtesy of London Terrariums.
Start with clean tools, healthy plants, sterile soil. High humidity levels make perfect conditions for molds and fungi to establish, especially if terrariums are overcrowded.
Photograph by John Merkl for Gardenista.
Succulents and Cacti Have Rotted Away
For more, see Gardening 101: How to Plant an Open Terrarium.
Open terrariums for desert-dwelling plants are very popular, but keeping cacti and succulents happy in a container with no drainage requires a knife-edge watering technique: too little and the plants won’t grow, or worst-case scenario, will shrivel.
An imported specimen case made of mango wood has a metal humidity tray and is $128 from Terrain.
More Help: Terrarium Workshops