Maple Aggregates Ltd - Importers and Distibutors of Specialist Minerals (Pumice Importer UK)

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Pumice in Horticulture

Yali pumice's fine qualities of constant specification, long term durability, environmentally friendly behaviour, together with it's financial efficiency make its use as a substrate for any crops extremely viable. The reserves available from the quarry are in excess of 100 million tonnes.

  • Hydroponic crops of flowering plants
  • Hydroponic crops of vegetable plants
  • A component of growing medium for pot plants
  • Soil improver
  • Improvement and drainage of top soil
  • Landscaping

Yali pumice is available in various grades, the 0-3 mm and 0-8 mm grades have been successfully used in the Hydroponic Industry. The material's excellent "sponge like" characteristics provide the all important water retaining properties, while also giving good drainage and ventilation to the plant's root system. Generally pumice is placed into the plant container; the volume per plant is determined by how densely the crop is planted, eg: 2 litres per plant for Chrysanthemums/Lettuces and up to 10 litres for sparsely planted crops such as Cucumbers. Pumice is very financially efficient and easy to use. It can be reused many times, on average up to 6 years for Carnations (3 successive crops) with outstanding results.

Physical properties of pumice

The apparent specific gravity (ASG) of non-processed pumice is 0.8kg/litre ASG is reduced to approximately 0.62-0.63 kg/litre when pumice is rinsed or sieved.

The total porosity of Yali pumice is 70-75% (sieving and rinsing tend to increase this value). the pH is 7.3. The water holding capacity of pumice (0-3mm) is almost 30%.

Chemical properties of pumice

Due to its very low exchange capacity (5-6 meq per 100g), Yali pumice is chemically inactive. Measurements have shown that the electrical conductivity of a 1:1.5 extract from samples of unused Yali pumice, which has not been sieved or rinsed, is approximately 0.2dS/m. As for pH, pumice has a neutral reaction and, therefore, pH is easily and efficiently controlled in the area of plant roots through the composition of added nutritive solutions.

The typical chemical composition of Yali pumice is:

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