To mix your own desert vivarium substrate, add these ingredients:
2 Parts Natural Sand: Natural sand is composed of a variety of particle sizes, with both very fine material (clay) and larger grains up to the size of a small pea. It may seem “dirty” to you. This is good. Some commercial sands that usually qualify would include decomposed granite (DG) and other crushed rock sands, such as crushed sandstone. The best place to look for these sands is at rock supply companies. Most carry DG and other natural sands. Sandy soils collected from unpolluted desert or arid areas will work, but not dirt from your yard. Some home improvement warehouses carry DG in bags labeled as “builder’s” or “all-purpose” sand, used for making concrete or a base for brick paving. I do not use aquarium sand, play sand (used for sandboxes, etc.), or silica sand, because they usually have uniform grains or only larger grains. Don’t use sand or rocks from the beach. They may contain excessive amounts of salts that will harm your plants and animals.
1 Part Ground Coconut Husk Fiber (Coir): Soaked and drained several times to remove any possible excess salts, then thoroughly squeezed out and fluffed up. Coconut husk fiber can be found in most pet and reptile shops.
Fertilizer: About ¼ cup per 1 gallon of substrate mix. Use a good all-purpose granular fertilizer with trace minerals. Most fertilizer packages have three large numbers on the label that indicate the percentages of the three major components – nitrogen, phosphate and potash. These numbers should be about equal or with slight variation (for example, 10-10-10 or 12-5-7, etc.). The most common and important trace minerals that should be included are boron, copper, iron, manganese, molybdenum and zinc. All of this information should be listed as a guaranteed analysis somewhere on the package.
Sulfur: 1 teaspoon per gallon of substrate mix. Powdered sulfur is available at most nurseries and home improvement warehouses. It may be packaged as a soil acidifier or “blueing formula” for hydrangeas and other acid-loving plants. Most of the natural sands used to make this mix are alkaline to some degree, so sulfur is used sparingly here to buffer, or balance out, the mix, making it more neutral.
Neither the fertilizer nor sulfur will harm your animals when used as directed here.
Mix all ingredients together thoroughly and add just enough water to make slightly moist. Set aside, covered, in a cool or shady place to settle for two to three days.
Place the mix in your vivarium, creating flat areas, slopes, hills and other landscape features as you wish. Pack the mix in firmly. Usually, rocks are placed in the landscape after the mix, but some large rocks may need to be placed first, as described in the article. Put in your plants. After your landscape is created to your liking, use a spray bottle with distilled water and lightly spray down the surface to help it settle and compact further. You should end up with moist, but not wet, substrate.
Allow the upper layer to dry out without disturbing it. A nice crust should form. This may take a few days, depending on your climate. You should be able to see differences in the color of your substrate through the tank glass; upper, dryer levels are lighter while lower, moister layers are darker. You can test for moisture by sticking your finger down into the substrate in one corner. It should feel just moist, but never wet, near the bottom. Once your substrate is at this point, you are ready to add your lizards. Allow your lizards to dig burrows as they wish. Being able to do this is mentally stimulating and makes many lizards feel happy and secure. You can remove the excess mix they dig out, or artistically contour and incorporate it into the landscape as they create their deposits.
Want to read the full story? Pick up the December 2010 issue of REPTILES, or subscribe to get 12 months of articles just like this.