Our Modified ABG Mix Recipe (Quick Reference) | Ingredient | Amount | Purpose | |---|---|---| | Sphagnum moss | 12 quarts | Moisture retention, slow food source | | Coco coir | 6 quarts | Structure, moisture balance, bulk | | Orchid bark | 4 quarts | Drainage, aeration, food source | | Horticultural charcoal | 2 quarts | Odor control, microbial support | | Worm castings | 2 quarts | Nutrition, beneficial microbes |
Total yield: Approximately 26 quarts (enough for multiple enclosures) Cost: $15 to $30 depending on where you source materials Best for: Tropical and temperate isopods, springtails, bioactive terrariums, vivariums
Written by the team at Creature Cache, based on firsthand use across all of our breeding colonies in Southern California. Updated 2026.
ABG substrate is the most widely used substrate mix in the bioactive and isopod hobby. The name comes from the Atlanta Botanical Garden, where the original recipe was developed for tropical vivarium setups. Over time it has become the standard foundation for dart frog vivariums, bioactive reptile enclosures, and isopod breeding colonies.
The original ABG recipe uses tree fern fiber, peat moss, charcoal, sphagnum moss, and orchid bark. We have modified the formula based on what we have seen work best across our own isopod colonies. Our version swaps tree fern fiber (which is expensive and increasingly hard to find) for coco coir, and replaces peat moss with worm castings for added nutrition. The result is a substrate that holds moisture well, provides food for isopods and springtails, supports burrowing, and stays healthy long term.
This guide breaks down every ingredient, explains why it matters, and walks you through mixing and hydrating your own batch.
Why Substrate Matters for Isopods
Isopods do not just live on their substrate. They eat it. They burrow in it, molt in it, lay eggs in it, and slowly break it down over time. A bad substrate choice can crash a colony. A good one does half the work for you.
The ideal isopod substrate does four things: it retains moisture without getting waterlogged, it provides nutrition as it decomposes, it stays loose enough for isopods to burrow, and it supports beneficial microorganisms like fungi and bacteria that isopods feed on.
ABG mix does all four, which is why it has become the default recommendation for both bioactive setups and standalone isopod colonies.
Ingredient Breakdown
Sphagnum Moss (12 quarts)
Sphagnum moss is the backbone of the mix. It holds an enormous amount of water relative to its weight, which keeps the substrate moist between mistings. It also creates a slightly acidic environment that slows the growth of harmful bacteria.
Isopods will eat sphagnum over time, though it breaks down slowly. It is particularly useful for creating moisture pockets within the substrate. Use dried, long fiber sphagnum, not the milled powder version. Long fiber holds its structure better and lasts longer.
Coco Coir (6 quarts)
Coco coir adds bulk and structure to the mix. It helps the substrate hold its shape while still staying loose enough for burrowing. It also retains moisture reasonably well.
Coco coir on its own is not a great isopod substrate because it has no nutritional value. Isopods cannot eat it and do not benefit from it directly. But as part of a mix with nutritious components like sphagnum, worm castings, and leaf litter, it works well as a structural base.
Use the brick form that you hydrate with water, or loose bagged coco coir. Avoid anything with added fertilizers.
Orchid Bark (4 quarts)
Orchid bark provides drainage and aeration. It keeps the substrate from compacting over time, which is important for burrowing species. Orchid bark is technically fir bark, and while it is not the most nutritious material, isopods will slowly feed on it as it decomposes.
The chunks also create small air pockets in the substrate that help with airflow and prevent anaerobic conditions. Use a fine to medium grade orchid bark. Large chunks will not integrate well into the mix.
Horticultural Charcoal (2 quarts)
Charcoal helps control odor by absorbing byproducts of decomposition. It also provides surface area for beneficial microbes to colonize. Springtails in particular seem to thrive in charcoal heavy environments.
Isopods do not eat charcoal and do not get direct nutritional value from it. Over time, as frass builds up and other materials break down, the charcoal remains behind which can make the substrate clumpy. For this reason we keep the charcoal proportion relatively low compared to the original ABG recipe.
Use horticultural charcoal, not activated charcoal or briquettes. Briquettes contain additives that can be harmful.
Worm Castings (2 quarts)
Worm castings are the nutrition powerhouse of the mix. They are packed with beneficial microorganisms, natural nutrients, and organic matter that isopods can feed on directly. Worm castings also introduce the kind of microbial life that kickstarts the biological activity in your substrate.
This is our substitution for the peat moss in the traditional ABG recipe. Peat moss is nutrient poor and is a nonrenewable resource. Worm castings provide far more biological value and help the substrate become a living ecosystem faster.
Use pure worm castings with no additives. They are widely available at garden centers and online.
What We Left Out (and Why)
Tree Fern Fiber
The original ABG recipe calls for tree fern fiber. It is an excellent material for drainage and aeration, and it breaks down very slowly. The problem is that it has become expensive and difficult to source. Coco coir fills a similar structural role at a fraction of the cost. If you can get tree fern fiber affordably, you can add 2 to 4 quarts in place of some coco coir.
Peat Moss
Peat moss is in many commercial ABG mixes. It retains moisture well and creates an acidic environment. However, it is harvested from ancient bogs and is considered a nonrenewable resource. Worm castings give you better nutrition and microbial activity. If you prefer to use peat, substitute it for the worm castings at a 1 to 1 ratio.
Perlite
We do not use perlite. While it is commonly added to potting mixes for drainage, it serves no purpose in an isopod substrate. Isopods do not eat it, it does not break down, and it floats to the surface when the substrate is misted. It is also a minor ingestion risk. Skip it.
How to Mix
Start by hydrating the sphagnum moss and coco coir separately. Sphagnum needs to be soaked in water for 10 to 15 minutes and then wrung out until it is damp but not dripping. Coco coir bricks should be broken apart and hydrated according to the package directions.
Once all ingredients are prepared, combine them in a large container or plastic storage bin. Mix thoroughly with your hands until everything is evenly distributed. The finished substrate should feel damp but not soggy. When you squeeze a handful it should hold its shape but not release water.
If it feels too dry, mist lightly and mix again. If it is too wet, add a small amount of dry coco coir or orchid bark to absorb excess moisture.
How to Use
Spread 2 to 3 inches of substrate on the bottom of your isopod enclosure. This gives your isopods enough depth to burrow, molt, and lay eggs below the surface.
On top of the substrate, add a thick layer (1.5 to 2 inches) of leaf litter. Oak and magnolia leaves are the best choices. The leaf litter is the primary food source for most isopod species. The substrate supports the ecosystem underneath while the leaf litter provides the buffet on top.
Add cork bark flats for hides, a clump of damp sphagnum moss on one side for a moisture gradient, and a piece of cuttlebone for calcium. Then add your isopod colony and springtail culture.
How Long Does It Last
A properly set up ABG substrate should last 6 to 12 months before it needs to be refreshed. Over time, the organic materials will break down and the substrate will compact and lose its structure.
Signs it is time to refresh: the substrate looks more like dirt than a mix of distinct materials, it is not holding moisture well even after misting, or it smells sour.
When you refresh, you do not need to replace all of the substrate at once. Remove the top layer of broken down material and add fresh mix on the bottom. This preserves the microbial colonies that have established in the enclosure.
Scaling the Recipe
The ratios above yield approximately 26 quarts. Here is how to scale for different needs.
For a single 6 quart bin: use 3 quarts sphagnum moss, 1.5 quarts coco coir, 1 quart orchid bark, 0.5 quart charcoal, 0.5 quart worm castings.
For a large 32 quart colony: double the base recipe (24 quarts sphagnum, 12 quarts coco coir, 8 quarts orchid bark, 4 quarts charcoal, 4 quarts worm castings).
The ratios are approximate. You do not need to be exact. The important thing is maintaining the general proportions so the mix retains moisture, drains well, and provides nutrition.
Where We Use This Mix
We use this exact substrate recipe across all of our breeding colonies at Creature Cache, including Durian Spiky (Laureola sp.), Dairy Cow (Porcellio laevis), Powder Blue (Porcellionides pruinosus), and Tropical Pink springtails (Coecobrya sp.). It has been our standard mix since we launched and we have had consistent results with every species.
Visit creaturecache.com to see our current species availability, or join the waitlist for early access to new drops. Every waitlist member gets a free 16oz springtail culture with their first order.
Common Questions About ABG Substrate
What does ABG stand for? ABG stands for Atlanta Botanical Garden, where the original substrate recipe was developed for tropical vivarium setups. It has since become the most widely used substrate mix in the bioactive and isopod hobby.
Can I buy premade ABG mix instead of making my own? Yes. Several companies sell premade ABG mix including Josh's Frogs and Pangea Reptile. Premade is convenient but more expensive per quart than mixing your own. Making your own also lets you customize the ratios for your specific needs.
Is ABG mix good for isopods? Yes. ABG mix provides moisture retention, drainage, nutrition, and burrowing structure, which are the four things isopods need from their substrate. It works for both tropical and temperate species, though arid species may do better with a drier mix that includes more topsoil.
Do I need to sterilize ABG substrate before using it? We do not sterilize our substrate. The beneficial microbes in the worm castings and sphagnum are part of what makes the mix work. If you are concerned about pests in raw materials, you can freeze individual ingredients for 24 to 48 hours before mixing, but we have not found this necessary.
Can I use ABG mix for plants? Yes. ABG mix is excellent for tropical plants, orchids, and terrarium plants. It was originally developed for planted vivariums. You can pot houseplants directly in it.
Why no perlite in your recipe? Perlite does not benefit isopods. They do not eat it, it floats to the surface when you mist, and it does not break down. It is also a minor ingestion risk. Orchid bark handles the drainage and aeration role better in an isopod specific mix.
How deep should the substrate be? Two to three inches for most enclosures. This gives isopods enough room to burrow, molt underground, and lay eggs in the substrate. Shallower than 2 inches limits burrowing behavior.
How often do I need to replace ABG substrate? Every 6 to 12 months depending on colony size and how fast the substrate breaks down. Refresh by removing broken down material from the top and adding fresh mix to the bottom to preserve established microbial colonies.
Can I use ABG mix for springtail cultures? Yes. Springtails thrive in ABG substrate. We use it for our Tropical Pink springtail (Coecobrya sp.) cultures. They can also be cultured on clay or charcoal substrates, but ABG works well if you want a single substrate system for both isopods and springtails.