PyroClay Mineral Supplement
Silicon is the second most abundant element on the
planet. (oxygen is first and aluminum is third.) The Earth's
crust consists mostly of silicone dioxide (plain sand), and
silicates which vary widely in composition. Sheet silicates,
compounds of silicon, oxygen, metals and carbonates
are rarely consistent in elemental make up. The most
common elements found in sheet silicates are aluminum,
iron, titanium, magnesium, calcium, lithium, manganese,
sodium, and potassium. Hundreds of mineral silicates
occur in the Earth's crust. Silicon is readily available for
plant assimilation as silicic acid. Silicic acids can be
extracted from sheet silicates in the form of monosilicic
acid, orthosilicic acid and metasilicic acid. Standard
nutrient formulations often ignore the existence of silicon
as an essential element. Soil is the mineral substrate for
most of the worlds plant life. Soil water contains silicon,
mainly as silicic acid (H4SiO4). Usually in concentrations
ranging from 50 to 400 ppm. Silicon is readily absorbed
so that terrestrial plants contain it in appreciable
concentrations, ranging from a fraction of 1% of the dry
matter to several percent, and in some plants up to 10%
or even higher. In spite of this prominence of silicon as a
mineral constituent of plants, it is not counted among
the elements defined as “essential”. Ample evidence is
present that silicon, when readily available to plants, plays
a large role in their growth, mineral nutrition, mechanical
strength, and resistance to fungal diseases, herbivory,
and adverse chemical conditions of the medium.
Properties of Sheet Silicon Clay
A common source of silicon is clay. Adding a pinch of
clay to a soil or soilless mix and the plants seemed to be
healthier, grow better, and flowers showed better color.
In addition to the primary silicon/metal oxide content of
the clay, most clays contain small amounts of 97
elements: 5 % iron, 3 % calcium, 2 % each magnesium,
sodium, and potassium and the remaining 92 trace
elements are estimated to be only one percent in total.
For purposes of agriculture and horticulture, the best of
this group are the aluminum silicates. Silicates are a
decisive factor in the healthy development of plants. Not
only for the silicic acid content, but also for trace elements,
pH buffering, and enhancement of the microbial
population in the growing medium.
Research has clearly shown that readily available silicon
plays a large role in growth, mineral nutrition, mechanical
strength, resistance to fungal diseases, and adverse
chemical conditions within the root zone. Plants absorb
silicon in the form of silicic acid, H4SiO4. In soil
environments, silicon in this form is available in the same
relative concentrations as K, Ca, and SO4. It is obvious
that silicon and other rare earth elements are of benefit
as a nutrient component for greenhouse and hydroponic
growing systems. The real problem for growers has been
finding a source of them in an economically and useful
form. Potassium silicate is too pH sensitive and
expensive, and pure silicic acid is not feasible as an
additive. Pyrophyllite clay is the natural answer.
Pyrophyllite Clay
Pyrophyllite Composition
Al2Si4O10(OH)2 Aluminosilicate (aluminum silicate
sheet) A comparison of two growing mediums, one sand
with clay colloids, and the other a hydroponic solution,
each with an equal portion of soluble salts showed that
the absorbed ions of the clay resulted in greater plant
growth. Clay surfaces adsorb large amounts of plant
nutrients without any appreciable change in the osmotic
concentration of the growing medium or fluctuation of
pH. Additionally, clays increase the cation exchange
capacity of the substrate. Pyrophyllite is a relatively
scarce clay, with very few deposits being commercially
mined. The most interesting aspect of the pyrophyllite
clay is the bond which holds it together. This clay is held
together by a Van der Waal bond. This is the weakest
bond which can hold elements together. The potential
bonding with the water is stronger than the bond which
holds the clay together. The result is that when the clay
is exposed to water, it literally falls apart and the clay
becomes a slow release source of silicic acid in two forms.
When the PyroClay is dissolved before it reaches the
roots there is sufficient silicic acid present to neutralize
the antagonistic action of the aluminum. There have been
no negative responses as long as the roots do not grow
directly into the PyroClay in its dry form. The reduced
fungal infections, resulting from the use of PyroClay, are
easily explained by the presence of available silicic acid.
Documented Results
PyroClay has been beneficially used on a range of crops
including; tomatoes, cucumbers, peppers, lettuce,
chrysanthemums, african violets, basil, rosemary,
bedding plants, poinsettias, aquatic plants, alstromeria,
roses, tree seedlings, rice, golf courses, plus a host of
others. It has been used in nutrient solutions, both drain
to waste and recycling, and incorporated into all types of
grow media. Also as a foliar dust or spray, or as a topical
media dressing.
The range of trials we have supervised with greenhouse
growers is extensive. In no case has a negative response
on yield been experienced. A tomato grower who lost
30% of his crop to botrytis last year, used PyroClay as a
dusting, once a week for the next year. His loses to botrytis
were zero. A cucumber grower, who was using potassium
silicate in his irrigation program, put 50 grams of PyroClay
on top of each transplant block, in several bays of the
range. The treated plants were the earliest to produce,
the highest producers, and resisted powdery mildew in
spite of the fact the rest of the range became heavily
infected. Another grower with phytophthora in his water
supply, introduced PyroClay into his storage reservoir.
Within days, there was no evidence of phytophthora in
the growing system.
