There is no single topsoil-and-sand ratio that certifies an arid enclosure for every bearded dragon or leopard gecko. Use a species-specific care plan, confirmed ingredients, and a clearly measured recipe rather than treating the percentage as the safety test.
Separate the two animals
Bearded dragons and leopard geckos are often grouped together in shopping advice, but they are not the same species. Their enclosure design, behavior, health status, and care requirements need separate consideration. The fact that both may use an arid-style layout does not make every ground material interchangeable.
The RSPCA bearded dragon guide discusses loose material in the context of suitable care and healthy adults. ReptiFiles' leopard gecko substrate page gives a different detailed approach. Read the whole relevant care source before selecting a mixture.
If the animal is newly acquired, unwell, or needs close observation, get appropriate veterinary advice about the enclosure. A permanent naturalistic blend and a temporary observation floor solve different problems. Do not force a complicated ground system into every stage of care.
What published recipes illustrate
SPCA New Zealand's bearded dragon care article gives a topsoil and washed-play-sand example. ReptiFiles currently describes a leopard-gecko mixture including topsoil, sand, and clay, measured by volume. These examples show that sources make recipe choices within a husbandry approach rather than sharing one universal two-ingredient formula.
A recipe is not a claim that any garden topsoil or any sand will work. The ingredient specification is part of the recipe. Do not replace play sand with unconfirmed reef sand or clay with unspecified fill dirt simply because the names sound related.
Swift does not certify its unconfirmed soil or fill dirt by repeating one of these ratios. Material attestations must come from the store for the actual batch. Until they do, the site withholds animal-use recommendations and keeps those products unpublished.
Measure volume consistently
If a recipe is stated by volume, use the same clean measuring container for each part. Do not measure one ingredient as a loose cup and another as a compressed bucket without recording the difference. Consistency makes the mixture understandable.
For an illustrative 10 liter trial blend at 70 percent soil and 30 percent sand, the chosen volumes would be 7 and 3 liters. That is a math example, not a prescription for an unspecified animal. A 60, 30, and 10 percent three-part recipe would use 6, 3, and 1 liter in the same total.
Equal weights do not recreate those volumes because the ingredients have different bulk densities. If you need to order bags sold by weight, calculate each ingredient's volume first and convert using its own explicitly estimated density. Keep the estimated ordering mass separate from the recipe itself.
Confirm every ingredient
For soil, ask about fertilizer, pesticide, herbicide, manure, and other additives rather than relying on one marketing word. For sand, ask for the actual material and grading required by the care source. For clay or another component, identify the product and its intended use.
A natural-looking brown material is not automatically clean. An unconfirmed material is not made suitable by washing, drying, or mixing it with something familiar. Resolve the source and treatment information before preparing the blend.
Keep the labels and batch information. If the recipe works well, those records tell you what you actually used. If something is unclear later, they support a useful conversation with the supplier or veterinarian rather than a guess based on the enclosure's appearance.
Match structure with maintenance
A burrowing ground needs to behave as intended, but a hand-squeezed sample cannot certify safe tunnels for every animal. Test the intended material arrangement outside an occupied enclosure and follow species-specific guidance about depth and structure.
Keep heavy stone, hides, and branches supported independently of loose ground. Digging can change the shape of a layer. Do not use compacted material as the only thing stopping a heavy slab from falling into an excavated space.
Plan how to remove waste and inspect the floor without destroying the entire arrangement. A uniform display surface may hide a service problem. Leave access to the places the animal is likely to use rather than designing only from the front photograph.
Arid does not mean ignore moisture
The MSD Veterinary Manual explains that substrate choice depends partly on the environmental conditions a reptile needs. Dry-looking scenery is not a measurement of the conditions inside a hide or beneath the surface.
Follow the relevant care plan for ventilation, localized humidity, temperature, and monitoring. Do not prescribe one watering routine for every enclosure. A deep layer in a poorly ventilated tank is different from a shallow trial container even when both began with the same recipe.
If a mixture is moistened for preparation, the readiness of the completed enclosure needs appropriate checks before the animal is introduced. Do not use a fixed day count from another room or another season as proof that the conditions match.
Calculate after the design decisions
Measure the inside footprint and intended depth. The calculator can estimate volume and the masses for confirmed ingredients. It cannot determine the animal's health, approve a particular loose substrate, or supply missing material facts.
Make a small documented trial before scaling a recipe to the enclosure. Label the components and use the same volume measure for each one. Keep some unmixed samples identified for comparison. If the handling or final condition is unexpected, this record lets you revisit a particular ingredient or preparation step rather than guessing inside a finished enclosure.
The soil catalog keeps unconfirmed materials unavailable. Continue with clean soil selection, burrowing substrate structure, and basking stone planning before buying a blend by a familiar-sounding ratio.