Pumice 1–7mm is a washed and screened horticultural pumice for improving drainage, aeration and structure in potting media. This porous volcanic rock can be blended into growing mixes for cacti, succulents, bonsai, aroids, orchids and other plants that benefit from an open, free-draining root zone.
Unlike lightweight amendments that may shift or float during watering, pumice provides durable structure while holding a small amount of moisture and nutrients within its pores. It is suitable for custom potting mixes, raised garden beds, propagation, hydroponic applications and no-till growing setups.
Key benefits
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Improves drainage: Creates spaces within the growing mix so excess water can move through more freely.
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Supports root-zone aeration: Helps maintain air pockets around roots and reduces compaction.
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Balances air and moisture: The porous particles retain some water while keeping the mix open and well drained.
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Maintains lasting structure: Durable volcanic rock does not quickly break down within potting media.
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Ready for horticultural use: Pre-washed and screened to reduce fines that may settle within the mix.
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Versatile 1–7mm grade: Suitable for small pots, detailed bonsai work and general potting-media blends.
Best suited to
- Cactus and succulent potting mixes
- Bonsai growing media
- Chunky aroid and indoor plant mixes
- Orchid and propagation blends
- Raised garden beds and no-till soil
- Hydroponic and reusable growing-media applications
For more detail on matching pumice grades to different growing uses, see our pumice stone guide for Australian growers.
How to use it
Blend the horticultural pumice evenly through your chosen potting soil, bark, coir or other growing-media ingredients. The appropriate amount depends on the plant, container and drainage requirements. A 1:1 blend with an existing potting mix can provide a more open structure, while cactus and succulent mixes may contain up to approximately 70% pumice where a particularly free-draining medium is required.
Although the pumice is pre-washed and screened, you may give it a quick rinse before use to remove any remaining handling dust. Watering frequency may need to be adjusted after adding pumice because the amended mix can drain and dry differently.
For a deeper comparison of how pumice and perlite behave in potting mixes and living soil, see our pumice vs perlite guide.
Choosing the right option
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2L: Suitable for testing a new mix or repotting a few small plants.
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5L: A practical option for several pots or a small collection.
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10L: Suited to larger repotting projects and regular mix making.
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25L: Intended for bulk potting-media preparation, raised beds or larger plant collections.
Check before buying
- Particle size: 1–7mm
- Material: naturally porous siliceous volcanic rock
- Available in 2L, 5L, 10L and 25L quantities
- Pre-washed and screened to reduce dust and fine particles
- The larger bags can be heavy to handle and may attract higher freight costs
- This is a growing-media amendment rather than a complete potting mix
FAQs
What is horticultural pumice used for?
Horticultural pumice is added to potting media to improve drainage, airflow and physical structure around plant roots.
Can I mix pumice into existing potting soil?
Yes. It can be blended through an existing potting mix to create a more open and free-draining growing medium.
For more context on selecting the right base medium, see our potting mix vs garden soil guide.
If you’re blending pumice for bonsai, our bonsai potting mix guide for Australian growers covers practical ratios, particle size and drainage considerations.
Does pumice need to be rinsed before use?
This product is pre-washed and screened. A quick rinse is optional if you want to remove any remaining handling dust, particularly when potting indoors.
Can horticultural pumice be reused?
Yes. The durable particles can be reused after old organic matter is removed and the pumice is rinsed thoroughly.
Choose Pumice 1–7mm when you need horticultural pumice for building a durable, aerated and free-draining growing mix for pots, garden beds or specialist plant care.
