Pumice 4.5kg. (DISCLAIMER: This item is supplied in a clear bag and produced by opening a 25-litre bag) (about 4 to 5 litres in size)
Pumice is a light siliceous vesicular volcanic rock that is suitable for use in horticulture and hydroponics. Its porosity provides air spaces that maintain aerobic conditions around the roots while water is contained within the pores. Surface tension around the outside of the pumice particles increases water-holding capacity of the growing medium. Pumice is a popular growing medium for Cacti, Succulents, Bonsai, Orchids and many other plants.
Our pumice is mined from a land-based resource, within 50kms of Lake Taupo in the North Island of New Zealand, and it is characterized by its relative hardness and lightweight in comparison to competing aggregates. The washing and screening of our pumice particularly for horticultural applications means that no ‘fine’ particles are included. Unwashed pumice can cause ‘concreting’ and higher water holding capacity than required, consequently affecting root development.
This hardness and porosity allows free drainage lowering the risk of root-rot diseases.
Pumice grades supplied for horticultural uses include:
- 1-2mm (In clear bag)
- 1-7mm (In clear bag)
- 4-20mm (In clear bag)
- 7-20mm (In clear bag)
Frequently Asked Questions
Q. Which pumice grade is best for growing Succulents?
A. According to the manufacturer, they suggest using mostly 1-4mm with a little 4-10 mixed though. The pumice should also be mixed with 50 to 75% of fine to medium organic matter like compost and garden soil.
Q. What is the PH of this pumice?
A. According to the manufacturer "The pH of Pumice is typically pH 6.7 to 6.9"
Using Pumice for Growing Bonsai, Orchids, Cacti, Succulents & Other Plants
Pumice is a highly versatile, natural volcanic rock commonly used in horticulture. Its lightweight, porous structure makes it an excellent soil amendment for improving drainage, aeration, and moisture retention — all critical factors for healthy plant growth.
✅ Why Use Pumice for Plants?
Pumice offers several benefits across different types of plants:
- Excellent Drainage: Prevents waterlogging, which is crucial for plants prone to root rot like cacti, succulents, and bonsai.
- Aeration: The porous texture increases oxygen flow to roots.
- Water Retention: Absorbs water without compacting the soil, providing consistent moisture while still draining excess water.
- Long-Lasting: Doesn't break down like organic matter (e.g., peat or bark).
- Nutrient Retention: Pumice holds nutrients while keeping the soil loose.
🔑 How to Use Pumice for Different Plants
🌳 Bonsai
- Pumice is often used in bonsai soil mixes for its excellent balance of water retention and aeration.
- Common bonsai mix ratio:
- 50% Akadama (water retention)
- 25% Pumice (drainage + aeration)
- 25% Lava Rock (structure + drainage)
- Pure Pumice can be used for certain species like junipers during recovery periods.
🌵 Cacti & Succulents
- Pumice prevents the dreaded root rot by draining water quickly.
- Recommended mix:
- 50% Pumice
- 40% Cactus Soil or Potting Mix
- 10% Coarse Sand
- For desert plants, a higher pumice percentage (up to 70%) is ideal.
🌸 Orchids
- Orchids like Cattleyas, Phalaenopsis, and Dendrobiums benefit from pumice in their potting mixes.
- Pumice provides aeration around delicate roots while holding just enough moisture.
- Mix suggestion:
- 40% Pumice
- 40% Bark
- 20% Charcoal
🌿 Houseplants
- Use pumice as a topdressing to prevent soil compaction.
- Add 10-30% pumice to regular potting mixes for plants like:
- Alocasias
- Fiddle Leaf Figs
- Snake Plants
How to Use Pumice in Soil Mixes
| Plant Type | Pumice Percentage | Notes |
|---|---|---|
| Bonsai | 20-30% | Use in mix for drainage + aeration |
| Cacti & Succulents | 50-70% | Higher percentage for desert plants |
| Orchids | 30-40% | Mix with bark + charcoal |
| Houseplants | 10-30% | Improves drainage and aeration |
Pumice vs. Other Amendments
| Amendment | Drainage | Aeration | Longevity | Nutrient Retention |
|---|---|---|---|---|
| Pumice | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ |
| Perlite | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐ | ⭐ |
| Lava Rock | ⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ |
| Vermiculite | ⭐ | ⭐ | ⭐ | ⭐⭐⭐⭐⭐ |
🔍 What Size Pumice to Use?
- 1/8"-1/4" (Fine): Cacti, succulents, small bonsai, orchids
- 1/4"-3/8" (Medium): Bonsai trees, orchids
- 3/8"-1/2" (Coarse): Drainage layers or landscaping
How to Prepare Pumice
- Wash before use to remove dust.
- Mix directly into the soil or layer at the bottom of pots for drainage.
- Use as a top dressing to prevent soil from splashing during watering.
Where to Buy Pumice?
Pumice is available at:
- Garden centers.
- Bonsai supply shops.
- Online retailers like Enfield Produce Pet & Garden Supplies.
Conclusion
Pumice is a game-changer for plant lovers, offering long-term improvements to soil structure, drainage, and aeration. Whether you're growing bonsai, orchids, succulents, or houseplants — adding pumice can make a huge difference in plant health.
Would you like help creating specific soil mix recipes for your plants or finding where to buy pumice near you?