If you've spent any time in bioactive groups, you've seen "ABG mix" recommended for almost every tropical build. This guide explains what ABG mix actually is, why it works, which animals it suits (and which it doesn't), and how much you need.
What does ABG stand for?
ABG stands for Atlanta Botanical Garden. Horticulturists there developed the original blend to grow rainforest plants and house poison dart frogs in the garden's displays. Hobbyists adopted the recipe, and "ABG" became shorthand for a free-draining, chunky tropical soil that lets live plants grow without the substrate turning to mud.
What's in ABG mix?
The classic recipe is built from long-lasting, open ingredients rather than garden soil:
- Tree fern fibre or a coarse substitute for structure and airflow
- Sphagnum moss (milled or chopped) to hold moisture
- Fir bark or orchid bark for chunk and slow breakdown
- Horticultural charcoal to keep the mix open
- Peat or coco fibre to bind it together
Modern blends swap some ingredients for more sustainable ones. Our ABG Terrarium Mix blends sphagnum moss, melaleuca, coco husk chips and soil, so it holds humidity without packing down.
Why ABG mix works so well in bioactive enclosures
- It drains. Water moves through instead of pooling, so roots get oxygen and the enclosure doesn't sour.
- It resists compaction. Chunky ingredients keep air pockets open for months, which isopods and springtails need.
- It feeds the clean-up crew. Organic matter breaks down slowly, giving microfauna something to eat between leaf litter top-ups.
- It holds humidity without staying soggy. Perfect for tropical species that like 60–90% humidity.
Which animals is ABG mix good for?
Standard tropical ABG mix suits animals from humid forests:
- Crested geckos, gargoyle geckos and leachianus geckos
- Dart frogs, tree frogs and mantellas
- Day geckos and other tropical arboreal lizards
- Tropical isopods, springtails and millipedes
- Planted vivariums and closed terrariums with no animals at all
When not to use tropical ABG
Desert species like leopard geckos, bearded dragons and uromastyx need a drier, sandier soil that holds burrows, so use a semi-arid blend instead. Burrowing tarantulas and scorpions do best in a firmer mix that won't collapse, such as our ABG Tarantula Mix.
How deep should ABG mix be?
Use 8–12 cm (3–5 in) of ABG over a 3–5 cm drainage layer of clay bio balls, with a mesh barrier in between. Go deeper in corners where you'll plant larger species. For exact litres, see our guide: How much substrate do I need?
How to set up ABG mix
- Add a 3–5 cm drainage layer and cover it with mesh.
- Pour in the ABG mix dry and shape any slopes or hills.
- Water slowly until the soil is evenly damp but not dripping when squeezed.
- Plant first, then add leaf litter, moss and hardscape.
- Add springtails and isopods, and give the enclosure 2–4 weeks to settle before adding animals.
Frequently asked questions
Can I make my own ABG mix?
Yes, but sourcing tree fern, charcoal, bark and sphagnum separately in Canada usually costs more than a ready-made bag, especially for small enclosures.
How often do I replace ABG mix?
In a healthy bioactive build you don't replace it. Top up with fresh leaf litter and a little soil once or twice a year as it settles.
Is ABG mix safe for reptiles?
Yes, ABG mixes are made from natural plant materials and are widely used with reptiles and amphibians. As with any loose substrate, feed insects in a dish for animals prone to swallowing substrate.
Ready to build? Shop ABG bioactive soil mixes, shipped from Canada and priced in CAD.