A customer once brought me a bag of commercial “succulent soil” that, when I examined it, retained moisture for nearly two weeks after watering in a test pot — a genuinely concerning result for soil specifically marketed for plants that need to dry out relatively quickly between waterings. This experience, repeated across testing several different commercial products over the years, is exactly why I now make and recommend a DIY soil mix rather than relying on commercial products alone.
Why Drainage Is the Core Soil Requirement
As covered throughout earlier tutorials, succulents are adapted to arid growing conditions and are particularly vulnerable to problems when soil retains excess moisture for extended periods. This makes drainage — how quickly water moves through and out of the soil — the single most important characteristic of appropriate succulent soil, more important than nutrient content or other factors that might matter more for different plant categories.
Regular potting soil, formulated for plants with different moisture needs, generally retains water considerably longer than succulents tolerate well, which is why using regular potting soil for succulents is one of the most common, avoidable causes of the overwatering-related problems covered in earlier tutorials, even when the grower’s actual watering frequency seems reasonable.
My DIY Soil Recipe
After testing various ratios over years of nursery operation, this is the combination I have settled on and now use consistently for the large majority of my succulent collection:
Two parts regular potting soil (as a base providing some organic matter and basic structure, though notably this is a smaller proportion than many growers initially assume appropriate, given regular potting soil’s water-retention characteristics relative to succulents’ actual needs).
Two parts coarse sand (specifically coarse, not fine play sand, which can actually compact and reduce drainage rather than improving it — look for sand labeled as coarse or builder’s sand specifically formulated for drainage purposes).
Two parts perlite or pumice (these lightweight, porous materials create air pockets within the soil structure that dramatically improve drainage and prevent compaction, with pumice generally considered slightly superior by experienced growers due to its additional weight helping anchor top-heavy plants better than the very lightweight perlite, though both work reasonably well).
Mix these three components thoroughly until evenly combined throughout, rather than leaving them in distinct layers or pockets within your final mix, which would create inconsistent drainage characteristics throughout the pot depending on which layer a particular root happened to be growing through.
Why This Specific Ratio Works
The roughly equal-parts ratio across these three components produces a mix that drains considerably faster than straight potting soil alone, while still retaining enough structure and minimal moisture retention to support healthy root growth, rather than draining so completely and rapidly that the plant cannot access adequate water during its actual watering sessions.
This balance — fast drainage without being completely inert — is what distinguishes a genuinely good succulent mix from either standard potting soil (too much retention) or an extremely aggressive, nearly pure mineral mix sometimes used for specific specialized situations (potentially too little water retention for typical home growing conditions and watering schedules).
Testing Your Soil’s Drainage Directly
Rather than assuming any specific mix, whether homemade or commercial, automatically meets succulent drainage needs, I recommend a direct test: water a sample pot of your mix thoroughly, then monitor how quickly it dries.
For an appropriately draining succulent mix, the soil should feel noticeably dry to the touch (at least at the surface and upper portion) within a few days under typical room temperature and humidity conditions, rather than remaining visibly damp or cool to the touch for a week or more, which would suggest the mix retains moisture longer than ideal for most succulent species and typical home growing conditions.
This direct testing approach is exactly what revealed the problematic commercial product I mentioned at the beginning, and I recommend any grower genuinely uncertain about their current soil’s drainage characteristics perform this same simple test rather than assuming a product’s marketing claims accurately reflect its actual performance.
Adjusting the Ratio for Specific Situations
For particularly humid climates or environments: Consider increasing the proportion of perlite or pumice relative to potting soil, pushing toward something like one part potting soil to three parts combined mineral additives, to compensate for the additional ambient moisture your specific environment introduces beyond what the soil mix alone controls.
For particularly arid climates with low ambient humidity: A slightly higher potting soil proportion, perhaps approaching equal parts or even slightly favoring potting soil, can help retain enough moisture between waterings in environments where the mix might otherwise dry out almost immediately, requiring impractically frequent watering to maintain adequate moisture for healthy growth.
For very young or recently propagated plants: Some growers use a slightly less aggressive drainage mix for very young plants still establishing their root systems, since these younger plants sometimes benefit from marginally more consistent moisture availability during this establishment period compared to mature, well-rooted specimens.
Why Commercial “Succulent Soil” Varies So Much in Quality
This is worth addressing directly, since my opening example was not an isolated incident. The term “succulent soil” or “cactus soil” on commercial packaging is not subject to any standardized formulation requirement, meaning products labeled this way can vary considerably in their actual composition and resulting drainage characteristics, from genuinely well-formulated mixes to products that are barely modified from standard potting soil despite the specific succulent-oriented labeling and marketing.
This variability is exactly why I recommend either making your own mix using the recipe above, where you control and understand the exact composition, or at minimum, directly testing any commercial product’s drainage performance using the method described above before trusting it for your valuable plant collection, rather than assuming the specific labeling guarantees appropriate performance for actual succulent care needs.
Sourcing Ingredients
Potting soil, coarse sand, and perlite or pumice are generally available at garden centers, hardware stores with garden sections, or online retailers specializing in gardening supplies. Buying these components separately and mixing your own batch, while requiring more upfront effort than simply purchasing a pre-made bag, generally costs less overall for a given volume of usable soil, particularly if you maintain an ongoing collection that requires periodic repotting or fresh soil for propagation.
A Quick Reference Recipe Summary
| Component | Proportion | Purpose |
|---|---|---|
| Regular potting soil | 2 parts | Base structure and organic matter |
| Coarse sand | 2 parts | Drainage improvement, weight |
| Perlite or pumice | 2 parts | Aeration, drainage, prevents compaction |
Adjustment for humid climates: Increase mineral components (sand, perlite/pumice) relative to potting soil.
Adjustment for arid climates: Slightly increase potting soil proportion relative to mineral components.
What I Told the Customer About Her Commercial Soil
I showed her the direct drainage test result side by side with my own DIY mix tested under identical conditions, letting the visible difference in how quickly each dried speak for itself rather than simply asserting my recommendation without demonstrable evidence. She switched to mixing her own soil going forward, and reported noticeably fewer watering-related problems across her collection in the following months, consistent with what the drainage test had predicted before she ever made the switch.
What is your current soil situation — store-bought succulent mix, regular potting soil, or something else? Describe what you are using and I can help you assess whether a switch to a custom mix would likely improve your specific results.