Starting and maintaining a terrarium...
Step 1: Pebbles
Medium to small sized pebbles are placed on the bottom of your terrarium to form a sump for water to drain into.
Step 2: Activated Charcoal
Activated or Horticultural Charcoal acts as the Terrariums filter removing impurities from the water and the soil.
Step 3: Screening (optional but helpful) Putting a second layer of pebbles or a mat of Sphagnum Moss on top of the charcoal is helpful to stop the potting media washing through to the bottom. Always ensure that Sphagnum moss is from a sustainable source.
Step 4: Potting Media
This is the layer that you will plant into. Potting mix is fine too but avoid mixes with fertilizer added. Palm peat is a good mix to use with carnivorous plants.
Step 5: Top layer
Finish off with a layer of Pebbles or under plant with mosses or small plants like Babies tears.
For an open dry terrarium (no lid) cacti, succulents or wide leaved Tillandsia (Air Plants) work well. In humid terrariums (with a lid) try ferns, mosses, Babys Tears, Pot bellied figs or the range of small indoor plants available. Carnivorous plants will also work well.
A properly layered terrarium should be quite easy to care for. Place your terrarium near a bright window away from direct sun and give a good misting when condensation stops forming on the sides of the glass. A terrarium without a lid will need to be misted more frequently. If you have planted cacti or succulents, let the terrarium dry out properly between watering and ensure you use a vessel with no lid. Never pour water into your terrarium instead mist slowly until water has just started to collect in the bottom layer. Rotating your terrarium every 2 weeks will keep the moss green and growing evenly.