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This has been very successful and over the years many research projects have been tackled by university students. The association continues to go from strength to strength and serves the majority of the industry


On the 6th and 7th of June 2018, SGASA will be holding their annual symposium at Hudsons on Vredenheim wine estate. The symposium will cover interesting topics ( that you would not want to miss!




We at Sun Silicates play a crucial part in the horticultural industry.

Sun Silicates is the only company in South Africa that manufacture both Sunperl horticultural perlite and Culite-V (horticultural vermiculite), which are the two most important sub-starters in a growing medium.

Both are light, inert, non-organic substances that are good for maintaining aeration in the soil by maintaining space between the soil particles. However, they function differently in terms of their effect on water retention.

What is perlite

Perlite is the snowy white granular particles that look like small pieces of styrofoam you will see in some potting mediums.

Perlite is formed when volcanic mineral rock is heated quickly causing it to exfoliate/expand. The result is a very lightweight, porous material that is hard and does not break apart easily. It is inorganic and sterile, has a neutral pH and can hold 3-4 times its weight in water yet will not rot or become soggy.

  • Perlite absorbs considerable water into the tiny bubble holes. However, this water is not retained very well. It tends to drain out quite quickly.
  • Perlite should be incorporated into the seed sowing compost
  • Perlite is best for plants that need well drained soil as because of its irregular surface shape it does help aerate the soil.
  • Results for seed production using perlite are mixed, since the perlite does not absorb moisture.
  • Perlite is available in various size grades.
  • Perlite ideally works for starting salad greens and other fast growing seeds.


Seedlings growing in perlite

What is vermiculite

Vermiculite is a hydrated magnesium aluminium silicate mineral and can be found in various countries across the world. The vermiculite mineral is non-carcinogenic and 100% safe to use.

horticultural grade exfoliated vermiculite is the best choice for seed production. When added to soil, it holds moisture and reduces the need for watering.

  • Vermiculite acts like a sponge, holding moisture close to the roots of the plants.
  • The horticultural exfoliated vermiculite is also able to absorb excess water away from plants, this can help prevent mildew.
  • When soil is sandy, mixing horticultural vermiculite into the soil will help maintain moisture and also help air circulate.
  • Horticultural vermiculite is available in various grading sizes (four). From very fine to course.
  • Vermiculite can be incorporated into the seed sowing compost, in addition it can be used for seed covering and some have used it solely as a seed growing medium


Vermiculite can also be used as a seed covering material. Instead of using sieved compost to cover the seeds use a light covering of the horticultural vermiculite (fine grade). Excellent seed germination results have been achieved using this method for covering seeds.

To make a soil-free growing medium for seeds, combine vermiculite with peat (or alternative) or composted pine bark. This mixture retains air, nutrients and moisture. Very little watering is required.

Some have even used vermiculite alone, if this is your chosen method then you should feed the seedling with diluted fertilizer when the first true leaves begin to appear.


Seedlings growing in vermiculite


Come and visit the Sun Silicates team at their stand at the SGASA symposium for all your growing needs, troubleshooting and information. See you there!


For more information regarding the products that sun silicates have to offer, give us a call on 011 824 4600, or email us on

Sun Silicates

About Sun Silicates

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Sun Silicates (Pty) Ltd focuses on supplying high-tech consumable products to the chemical, metallurgical and agricultural industries. The company is customer and performance focused and we ensure our customers of quality products at competitive pricing.

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