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100% Organic and natural farming, landscaping, and gardening, with Diatoms

Diatomite, for optimum plant vitality

1. General

Diatomite is a naturally occurring siliceous sedimentary mineral compound from microscopic skeletal remains of a unicellular algae-like plant called diatoms. These plants have been part of the earth’s ecology since prehistoric times with diatoms inhabiting both fresh and salt waters for a very long period of time. As living plants, diatoms from microscopic shells from silica they extract for water. Diatomite deposits are formed when diatoms die leaving their shells to sink to the bottom of water bodies. These, shells from thick layers that are fossilized over a very long period of time – in what becomes dried lake and ocean beds.

The major constituent of diatomite is amorphous silicon dioxide (SiO2) with a minor amount of other minerals (aluminum, iron oxide, calcium hydroxide, magnesium, and sodium). However, not all diatomite is the same as deposits that come from different geological periods, and areas can vary in composition, making it more or less suitable for different applications.

Diatoms constitute a thick chalky sedimentary deposit consisting of the inorganic non-toxic skeletal remains of freshwater algae and phytoplankton. Typical diatoms exhibit lacework patterns of great variety and complexity, creating a high porous internal structure.

2. Agri Silica’s environmentally friendly products and fields of application


1 Silfos 170phosphate fertilizer with 30, 4 % SiO2
2 Magsilfos 45phosphatefertilizer with 26% SiO2
3 Diatoms concentrate in 10kg and 500kg bags
4 Diatoms Soilin 10kg and 500kg bags (price on request)
5 Diatoms pebbles 2-8mm (in 10 and 500kg bags) price on request
6 Diatoms pebbles8-25mm (in 10 and 500kg bags) price on request

Fields of application

  • Topdressing mixes
  • Rich source of Si for plants
  • General insecticide
  • General soil amendment
  • Hi Silica Growing media for lawns, turf, seedlings
  • Improving soil porosity
  • General potting
  • Potted plants requiring increase drainage
  • Orchid mixes
  • Hydroponics

Diatoms have a freshwater origin (as opposed to diatomite of marine origin with resulting high salinity levels) with minimal contaminants and salts that make most other sources unsuitable for horticulture.


Diatoms contain a high amount of water-soluble silica (120ppm vs. 10ppm of normal soil) available to plants.
Silica controls root system development and increases plant resistance to abiotic (e.g. insects, fungi, disease) stresses.

Benefits of silica include:

  • Silica is widely documented to stimulate Self Acquired Resistance (SAR) in plants. It strengths the cuticular cell wall and imparts physical resistance to disease, insect, and fungi attacks.
  • Silica increases the drought and salt resistance of plants.
  • Silica promotes the restoration of degraded soils and increases soil fertility.
  • Silica increases crop production/yield and quality.
  • Silica helps restore heavy metal and hydrocarbon-polluted areas.

Diatoms pebbles and concentrate improve the physical structure of the soil (It helps to break up heavy clay-based soils as well as retain moisture in light or sandy soils), helps retain moisture for longer periods (Diatoms can absorb up to 200% of its weight in water), enhances the movement of water to the root zone and provides a slow release of nutrients (it acts as a fertilizer carrier).

The porosity of diatomite contributes to its ability to draw water, while moving water and nutrients laterally throughout the medium, making Diatoms pebbles ideal for Hydroponics.

All plants, shrubs, vegetables, and fruit will benefit from the application of Diatoms diatomite.

Other benefits of using Diatoms diatomite include:

  • Diatoms diatomite contains small amounts of trace elements that are beneficial to plant growth.
  • Diatoms pebbles are multifaceted and vary in size. Because each pebble is Unique in shape it does not compact while in the pot. This leaves pockets, allowing air to penetrate and circulate to the root zone.
  • Diatomite is a fossil, making it natural, safe, and an environmentally conscious alternative.
  • Diatomite will not break down or decompose like other growing mediums.
  • Because diatomite is chemically inert it will not interfere with soil chemistry.
  • Harmless to humans and animals if digested.
  • The microscopic porous structure of each pebble provides effective thermal insulation to plants root zones.
  • When dry, diatomite is a natural insecticide. On contact with insects, it absorbs the epicutilar lipid layers (which consist of hydrocarbons, wax esters, and other organic chemical compounds) of the insect. This causes excessive water loss through the cuticle of the insect and ultimately death by desiccation (dehydration). Because it is a physical action (not chemical) that causes death, insects cannot build up resistance to diatomite.
  • Diatomite is pH neutral and stable and will not contribute to changes in pH.
  • Diatoms pebbles and Diatoms concentrate are heat sterilized in a rotary kiln at high temperatures.

3. Application rates and methods

It is important to saturate Diatoms Diatomite with water and nutrient as soon as possible upon application. This will achieve maximum benefit and optimum results.

1. Potting Mixes

The application rate for Diatoms pebbles should be around 30% to 50% blended with a normal potting medium and a standard fertilizing program.

For orchids the following mix is suggested as a starting point:
40% -Diatoms pebbles
50% -Perlite
10% Peat moss

We strongly encourage you to make up a few variations that you think will work for you and experiment with them to see what works best.

2. Top Dressing Lawns

Mix Diatoms concentrate with sand or soil at a rate of 50% concentrate and 50% sand/soil. Spread /blend evenly on the lawn at a rate of 2 liters per M2 and keep watered till grass grows through.

3. Turf Laying

Apply Diatoms pebbles at a rate of 5 litres (+-3.5kg) per m2 evenly beneath the surface, before laying turf.

4. Vegetables

And a handful of Diatoms concentrate or pebbles to the hole for transplants or into seed rows.

5. Trees and Large Shrubs

Diatomite pebbles help reduce the root damaging “bathtub” effect of trees planted in poor soil. Mix Diatoms pebbles into the backfill in a ratio of 25% to 33% by volume.

6. Roses

Apply Diatomspebbles at the rate of 5 liters (+-3.5kg) per bush, dug into the soil and a further 3 liters (+-2kg) around each bush.


Your No 1 supplier of Plant, Animal and Human Vitality!

100% organic - Phytoplankton Power!
Your 100% natural and organic way to
detox and improve your health.
Fostec P6
Your # 1 ready-mixed animal summer lick!
Fostec P6 with 20% DE
Your # 1 ready-mixed animal summer lick!
Fostec P12 with 20% DE
Supplies the producer of livestock with
a 12 % phosphate administering.
Diatoms Concentrate
A highly concentrated, two-in-one product that
enhances the growth of animals and heals
animals internally.
Diatoms Rolling Compound
For external application to game, cattle,
and horses - they roll in the product which is
spread on the ground.

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