Wait so can you explain how topsoil, sand, and decomposed granite makes a safe substrate? I'm confused because i thought most soils are toxic because of fertilizers and chemicals and that sand causes impaction. I have no idea how granite works or where to get it ;-;
Also, what are the best proportions for the top soil/sand/granite, and where did you get them from?
The topsoil used should definitely be organic. Note that topsoil is not potting soil! It is specifically labeled “topsoil”. It is primarily intended as fill to level ground and eliminate depressions in a yard. If it is organic it should be free of dangerous chemicals, and as it is not a potting medium it doesn’t have added fertilizers. It is purchased at a home improvement store or garden store.
Sand alone is definitely dangerous. Very few animals we keep live on loose sand in the wild. Some reasons it’s more dangerous than a mixed substrate are found in this post.
When mixed in with a proper complex substrate, sand will behave differently than when it’s on its own. It no longer rolls loosely over itself, allowing the substrate to hold its form with much lower moisture levels. It will be less likely to be easily lapped up, so impaction risk is lessened. It’s also easier for animals to move on (think of how difficult it is to walk in dry sand).
Decomposed granite is granite rock that has been weathered and broken down into small mixed particle sizes. It has pieces ranging from tiny pebbles, to sand, to silt. It is found at home improvement stores or purchased online.
These three ingredients are not the only possible substrate mix. Some other arid bioactive substrates include ingredients like compost, humus, dirt from outside (it must be from a safe, pesticide free area, etc.!), coco fiber in low amounts, Excavator Clay or other clay, and organic materials. The recipe I use I got from @tokays.
The ratio I used was approximately 50% topsoil, 25% sand, and 25% decomposed granite. However, this mixture needs to be adjusted according to the materials used, as the make up of different materials varies greatly by brand and location purchased.
It should be mixed together, and wet down, and then after it dries down it needs to be checked for how well it holds burrows and that when completely dry, it doesn’t compact hard or become dusty. This should be done before ever adding it to the enclosure and setting it up!
After setting it up, bioactive enclosures do best with a month to grow in, let CUC establish, and parameters be monitored and tweaked.Other aspects of husbandry, such as humidity, diet, temperatures, and so on, must be correct, or the risk of impaction is higher. Any loose substrate can be an impaction risk, so if a person is having difficulty with basic husbandry they should not attempt bioactive.
Check out my bioactive tag for more information. I encourage anyone considering bioactive to do a lot of research from many sources both on the care of the animal in question and bioactive enclosures for them.