“What size terrarium for succulents?” ranks among the most frequent questions I encounter from terrarium enthusiasts, and for good reason—getting the dimensions right can mean the difference between a thriving miniature ecosystem and disappointed plant parents watching their succulents struggle. The sizing question reveals something deeper about our desire to create perfect micro-worlds for these desert beauties.
Throughout my six years of designing terrariums, I’ve witnessed countless containers become either cramped prisons or oversized swimming pools for succulents. The magic happens when we understand that these drought-adapted plants need just enough space to establish their shallow root systems while maintaining the arid environment they crave.
What size terrarium for succulents?
The ideal terrarium container should be at least 2-3 inches deep to give succulent roots adequate room to spread out, with an opening wide enough for easy access during planting and maintenance. For optimal plant health, choose containers that are approximately 10% wider than your largest succulent, ensuring each plant has breathing room without creating excessive unused space.
Container depth requirements
Depth plays a crucial role in succulent terrarium success. A minimum depth of 1½ inches is necessary to provide sufficient growing medium volume, but this barely scratches the surface of what succulents truly need. When you factor in the essential drainage layer, soil depth, and root development space, that minimum quickly becomes inadequate.
The layered construction of a proper succulent terrarium demands careful depth calculations. Start with 1-2 inches of drainage material at the bottom, followed by 2-3 inches of specialized succulent growing medium. This creates a foundation that prevents root rot while providing adequate rooting space.
For containers housing multiple succulents, aim for 4-6 inches of total depth. This accommodates the drainage layer, soil depth, and allows room for future root growth without restricting plant development.
Spacing between plants
Space plants at least one inch apart to ensure adequate airflow and prevent root crowding. This spacing requirement significantly impacts your container size calculations, especially when planning arrangements with multiple species.
For multi-plant arrangements, provide half-inch to one-inch spacing between each plant for optimal results. Crowded succulents compete for resources and create humid microclimates that invite fungal problems—the opposite of what these arid-adapted plants require.
Consider mature plant sizes when planning spacing. That tiny Echeveria rosette will eventually spread to several inches across, while Haworthia species maintain more compact growth habits. Research your chosen species’ adult dimensions to avoid future overcrowding.
Container width considerations
Width directly correlates with both plant selection and visual impact. Narrow containers limit your design options and force plants into unnatural proximity, while excessively wide vessels can appear sparse and difficult to maintain.
Depending on container size, you might choose a single plant for smaller vessels, but multiple small succulents create more interesting displays. Calculate width by adding your planned plant diameters plus spacing requirements, then add 1-2 inches for visual balance.
For single-specimen displays, choose containers 2-4 inches wider than your plant’s current spread. This provides growth room without creating an overwhelming sense of empty space that can make maintenance challenging.
Opening and accessibility
Ensure the opening is wide enough for hands and tools to fit comfortably during planting. Narrow-necked containers may look elegant, but they create nightmare scenarios during maintenance and replanting.
Wide openings help with air circulation, which proves essential for succulent health. Stagnant air promotes moisture retention and fungal growth—conditions that quickly kill even the hardiest desert species.
Plan for long-term maintenance needs. You’ll need access for removing spent flowers, pruning overgrown sections, and eventually transplanting outgrown specimens. Containers with openings smaller than 4 inches become increasingly difficult to maintain as plants mature.
Size guidelines by plant count
Single plant containers: 3-5 inches wide, 3-4 inches deep 2-3 plant arrangements: 6-8 inches wide, 4-5 inches deep
4-5 plant displays: 8-12 inches wide, 5-6 inches deep Large arrangements (6+ plants): 12+ inches wide, 6+ inches deep
These guidelines accommodate proper spacing, drainage layers, and future growth while maintaining visual proportions that showcase your plants effectively.
Common sizing mistakes
Oversized containers rank among the most common errors I encounter. Large pots can have equally damaging results as small ones, plus increased risk of rot due to their ability to hold excessive moisture. Even with fast-draining soil, unused space retains moisture that plant roots cannot absorb.
Undersized containers create their own problems. Root-bound succulents cannot access adequate nutrition and struggle to establish stable anchor systems. They become top-heavy and prone to tipping as they grow.
Ignoring drainage requirements represents another frequent oversight. Beautiful glass bowls without adequate depth for proper layering doom even carefully sized plantings to eventual failure through poor drainage.
Conclusion
Just last month, I helped my neighbor Maria rescue her struggling succulent terrarium—a gorgeous but oversized fishbowl that had become a soggy mess despite her careful attention. By transferring her plants to appropriately sized containers with proper depth and spacing, we transformed her disappointment into a thriving collection that now graces her kitchen windowsill. The right container size isn’t just about aesthetics; it’s about creating the precise conditions these remarkable plants need to flourish in our homes, one carefully measured inch at a time.
El Castor is your exclusive terrarium guide.