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Vermiculite
Vermiculite is a naturally occurring mica material of laminar structure which has been heated in a furnace to create exfoliated granules with a very high surface area and inter-laminar air space (like a concertina).
The inter-laminar air space provides a very high pore volume, typically 96% of total volume. As with Perlite, pores may be filled with air or water, depending on size.
The cation exchange properties of Vermiculite act as a nutrient buffer, releasing added nutrients to plants in a form they can easily assimilate. In addition Vermiculite naturally contains magnesium, iton and potassium which are available for plant growth.
Benefits
- Eases re-wetting of growing media when it has dried out.
- Extends watering intervals.
- Improves growing media aeration.
- Acts as a nutrient buffer.
- The excellent insulation properties and ability to hold nutrients as well as air make it an ideal choice for seed composts.
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Sinclair Vermiculite FineGranule size: 1.0-3.0 mm
Total water-holding capacity: 419 ml/litre
Useful for aiding the water management of peat composts as it retains water more strongly than peat, so extending watering intervals and making it easier to re-wet. The nutrient buffering complements this water buffering action. Can also be used as a seed covering.
Use at up to 50% by volume.
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Sinclair Vermiculite MediumGranule size: 2.0-5.0 mm
Total water-holding capacity: 381 ml/litre
Useful for improving aeration without impacting adversely on water capacity or water retention. It can also be used for seed covering.
Use at up to 50% by volume.
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Sinclair Vermiculite CoarseGranule size: 5.0-10.0 mm
Total water-holding capacity: 322 ml/litre
Useful when higher aeration levels are required without impacting adversely on water capacity or water retention.
Use at up to 50% y volume.
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How to Use
Seed Germination
Use Fine Vermiculite mixed with seed composts at a rate of up to 50%.
This will aid aeration, improve water-holding capacity and speed up germination times.
Vermiculite can also be used on its own to cover seeds once sown.
Rooting Cuttings
Use Medium Vermiculite mixed with peat-based growing media at a rate of 10-25% to aid aeration and improve water-holding capacity.
It is particularly useful for soft-wood cuttings and leaf cuttings of many gesneriads and begonias.
Hard to root shrubs, including some magnolias and rhododendrons, can be rooted in a 50/50 mixture of Vermiculite and Perlite.
Potting Compost
Use Medium of Coarse Vermiculite mixed with peat-based substrates at a rate of 20-25% to improve and aid water-holding capacity.
Vermiculite also helps to absorb excess nutrients and improves re-wetting.
Information Sheet Download |
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Vermiculite Information Sheet
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