For a sealed environment, select small, slow-growing plants that thrive in high humidity and indirect light. Making a Bottle Terrarium + Closed Terrarium Basics
Gently remove your plants from their original pots and shake off excess soil.
: About 8 cm of high-quality potting soil or peat-free coir compost. For tropical plants, a mix containing sphagnum peat moss or coco coir is ideal. Step-by-Step Construction Guide bottle biosphere guide full
: Use a funnel to add your potting mix. Ensure the soil is deep enough (usually 5–8 cm) to anchor your chosen plants. Insert the Plants : Poke a hole in the soil using a stick or dowel.
: Pour in your pebbles, followed by a layer of activated charcoal. For a sealed environment, select small, slow-growing plants
To function as a closed system, your biosphere must include specific layers that handle drainage and filtration:
: A 3–5 cm base of small rocks, pebbles, or horticultural grit. This prevents water from pooling at the bottom and rotting the plant roots. For tropical plants, a mix containing sphagnum peat
: A thin coating of activated charcoal over the pebbles. This acts as a filter to keep the water "sweet" and prevent the growth of odors or harmful bacteria.