Pumice is offered in two particle sizes: fine (1–3 mm) and medium (3–6 mm), both in 40 L bags. It is a natural, porous, and very light volcanic rock that provides drainage and aeration to the substrate without compacting over time. The difference in particle size does not change the chemical properties, only the particle size and, therefore, the crop or system where it is most suitable.
🎯 Choose the variant in 10 seconds
- If your case is seedbeds, cuttings, bonsai or small pots: go to the fine particle size (1–3 mm)
- If your case is medium and large pots, succulents, orchids or drainage in gardening: go to the medium particle size (3–6 mm)
What to consider before choosing the variant
Both particle sizes share the same origin and properties: natural pumice in a 40 L bag, light, porous, and aesthetically discreet. The choice is based solely on particle size:
- Container size: small pots, trays, and bonsai require fine particle size, which maintains homogeneous contact with the root. Large pots and deep planters require medium particle size to take advantage of lightness without saturating deep areas.
- Crop type: fine roots and young plants (bonsai, cuttings, propagation) work better with fine. Thick roots and adult plants (succulents, orchids, tropical ornamentals) prefer medium because it provides air gaps between particles.
- Absorption capacity: pumice is very porous (alveolar) and absorbs water within each particle, gradually releasing it to the root. This property is similar in both particle sizes, but the fine offers more contact surface area per unit volume.
- Mixing with other substrates: fine mixes well with peat, coco peat, or vermicompost in proportions of 20–40%. Medium is preferred for cactus and succulent substrates (40–70% pumice) or as a drainage layer at the bottom of large pots.
- Top dressing: fine looks good as an aesthetic cover in small pots or propagation trays. Medium has more visual presence and is the choice for top dressing in medium and large pots, especially in succulent collections.
Fine particle size (1–3 mm): the subtle choice for bonsai and seedbeds
- Homogeneous distribution in small pots
- Suitable for akadama-style substrate in bonsai
- Excellent for rooting cuttings
- Capillarity: distributes moisture evenly
- Possible compaction in large pots
- Provides less air than medium in dense substrate
Fine pumice is the preferred choice for bonsai, where it is used pure or mixed with akadama and kanuma to create specific substrates depending on the species. It also works very well for rooting cuttings, succulent seedbeds, and small pots where limited space requires a particle that distributes uniformly. For cactus propagation, it is used pure or with 20–30% peat.
Medium particle size (3–6 mm): the standard for succulents and large pots
- Greater aeration: ideal for succulents and orchids
- Long-term structural stability
- Suitable as a drainage layer in large pots
- More visual presence as top dressing
- Leaves empty spaces in seed trays
- Not optimal for fine bonsai
Medium pumice is the standard option for cactus and succulent substrates, where it is used at 40–70% mixed with peat or coco peat. It also works very well with orchids (mixed with bark), as a drainage layer at the bottom of large pots (3–5 cm at the base), and as a decorative component in dry landscape planters. Its lightness makes it especially useful in pots for rooftops or suspended gardens where weight matters.
Comparative table of variants
Both particle sizes are chemically and mineralogically identical. The difference is only in particle size and, therefore, in how it behaves within the substrate.
| Feature | Fine | Medium |
|---|---|---|
| Ideal Use | Bonsai and seedbeds | Succulents and large pots |
| SKU | 921341 | 472834 |
| Particle Size | 1–3 mm (0.04–0.12 in) | 3–6 mm (0.12–0.24 in) |
| Aeration | Medium | High |
| Drainage | Medium | Fast |
| Capillarity | High | Medium |
| Alveolar Porosity | High | High |
| Volume per Bag | 40 L (10.6 gal) | 40 L (10.6 gal) |
| Structural Stability | Excellent | Excellent |
Use case matrix → recommended variant
| If your case is... | Recommended variant |
|---|---|
| Bonsai or akadama-style substrates | → Fine |
| Cuttings and cactus propagation | → Fine |
| Top dressing in small pots | → Fine |
| Substrate for cactus and succulent collection | → Medium |
| Orchid mixes (with bark) | → Medium |
| Drainage layer in large pots and planters | → Medium |
Before mixing pumice into your substrate, sieve it and rinse it with running water to remove dust and residual fine particles. This washing improves the visual transparency of the substrate (especially important for bonsai and succulents) and prevents fine particles from clogging the gaps between larger grains. Washed pumice drains better and retains its alveolar porosity over time.
Do not use pure pumice for plants with high water demand such as vegetables or tropical plants. Although pumice absorbs water within each particle, it releases most of it quickly and does not provide the water reservoir these plants need. For use as a single substrate, limit its use to cacti, succulents, and drought-adapted plants. For vegetables or tropical plants, mix it with peat, coco peat, or vermiculite.
Fine or medium for your substrate?
Tell us what you will grow (bonsai, succulents, orchids, gardening), container size, and the base mix you use. You will receive the exact particle size and recommended proportion for your case.
Frequently Asked Questions
Is pumice the same as perlite?
No, although both are lightweight, porous minerals. Pumice is a natural volcanic rock that is mined and crushed, with gray or cream particles and rounded edges. Perlite is a heat-expanded mineral with white particles and sharp edges. Pumice has better long-term structural stability and is preferred for bonsais and collector's items; perlite is lighter and more economical for commercial nurseries.
Pumice or volcanic gravel for succulents?
Both work, but they have distinct profiles. Pumice is lighter, more porous, and has a neutral light tone, ideal for technical collector's substrate. Volcanic gravel is heavier, less porous, but more decorative due to its color (red or black), and is more commonly used in landscaping and top-dressing. For serious cactus collections, pumice is usually preferred; for decorative landscaping, volcanic gravel.
Can pumice be reused?
Yes, it is one of the most reusable mineral substrates. After a growing cycle, remove the roots, sieve it to separate it from fines, rinse it, and disinfect it with a mild 1–2% hypochlorite solution or by pasteurizing with steam for 30 minutes. Pumice is structurally stable and can be reused for many cycles without losing porosity or drainage capacity.