The Truth about AgSil 16h / Potassium Silicate

Hello fellow organic enthusiasts,

From the information I've gathered in all my searches and in the sticky threads, it seems like a decent amount of "Organic" cultivators are using a 'Potassium Silicate' source, most commonly AgSil 16H.

I want to start an open and honest conversation about its place in the organic cultivators garden. There seems to be a misconception surrounding the product all together.

It is true that 'AgSil 16 H', or 'Potassium Silicate', is allowed for organic applications, but it is not an organic fertilizer.

Please take a moment to understand that I am not attempting to attack anyone's method or ideology, but instead sharing and seeking information. I am a synthetic cultivator attempting to make a transition to truly organic practices. I feel that turning our backs on the elephant in the room(AgSil) is not benefitial to our community or true to the practice we proudly claim. There are a lot of knowledgable and experienced gardeners here, our time and knowledge is the most valuable and powerful tool we have. I'm certain with a combined effort we can find the truth and quality substitute(horsetail?).

Most information will be taken from this article, I encourage everyone do their own research, read the article yourself, but you can find a summarized version below.

I would love to hear/see any and everyone's opinion/information relevant to the topic. If you are going to make factual claims, please bring substantial literature/documentation/sourcing.

Here's what I found on the subject.

"All TAP reviewers agreed that the petitioned substance should be considered synthetic. Two reviewers felt it should be prohibited. One of these reviewers cited the nature of potassium silicate as a highly soluble synthetic fertilizer, and also questioned its effectiveness as a fungicide. The other dissenting reviewer raised similar concerns, questioning the need for silica amendments in organic systems and the legitimacy of supporting evidence. Both of these reviewers indicated that use of the substance in organics should be revisited if and when the need, effectiveness, and mode of action are better demonstrated. The third reviewer was in favor of adding the substance to the List, with annotations. The reviewer viewed the potential benefits as significant, and felt that the substance ultimately is compatible with a system of organic agriculture."
(Source: USDA.gov)

"How It's Made:
Potassium silicates are manufactured using a calcination process that combines silica sand (SiO2) and potassium carbonate (K2CO3) at 1100-2300°F for up to 15 minutes (NOP Petition; Rawlyk and McDonald 2001). The two substances fuse into glass, which can be dissolved with high-pressure steam to form a clear, slightly viscous fluid, or cooled and ground into a powder. Carbon dioxide is evolved* from this reaction. The solution can be dried to form hydrous powder crystals of potassium silicate. "
(Source: USDA.gov)

* = evolution of carbon dioxide n. An expression of the rate at which carbon dioxide is produced by the body, usually given as the microliters of carbon dioxide produced in 1 hour by 1 milligram dry weight of tissue.
(Source: Google; Dictionary.com)


Notice all three TAP reviewers agreed that this substance is synthetic.
(Source: USDA.gov)

"The probability of environmental contamination during manufacture, use, misuse, or disposal of the substance:
As outlined in the “How Made” section, potassium silicate is made via calcination, or thermal conversion into an ashlike powder. The substance is produced by reacting high-silica sand and mined potassium carbonate, yielding potassium silicate and CO2 gas. The manufacturing process does not appear to pose a substantial risk of environmental contamination, outside of the upstream combustion of fossil fuels to power the reaction. There is no mention in the petition or in other literature of impurities resulting from the reaction, or the use of catalysts other than heat.

While the petitioner intends to use naturally occurring sand as a primary raw ingredient, silica-laden compounds used as silicon fertilizers for conventional agriculture are commonly sourced from industrial byproducts. These byproducts, referred to ubiquitously as slag, are impurities precipitated from the refining of mined materials and smelting of metal ores. Depending on the source, slags may also contain heavy metals associated with their origin or processing (e.g., uranium in phosphate ore, nickel, and zinc). Nonetheless, the use of silica slag fertilizers in agriculture is widespread, particularly in sugarcane fields and paddy rice systems. In conventional agriculture, calcium silicate slag (CaAl2Si2O8 or CaSiO3) is commonly used as a silica fertilizer (Tisdale et al 1999)."
(Source: USDA.gov)

Let's set our egos aside and find a solution.


P.S. I will update this thread as new information becomes available.

 

Thanks for the reply @donothinggardening!

I am cultivating comfrey myself, do you have a preferred application method? Composting, Anaerobic Fertilizer Tea, Mulching, etc?

I intend on composting when possible, and just began an AFT trial.

Thanks again for the input!

 

Hey guys,

Nice to see some strong and informational posts this morning.

I also like the idea of using plant sourcing as often as possible, but as mentioned above, it often boils down to ones patience and time-of necessity.

If you are using rice hulls in your soil, applying or mixing Malted Barley Powder into your soil, or composting using Dynamic Nutrient Accumulators(horsetail, stinging nettle, comfrey, dandelions, etc), and even using manure compost, you are likely incorporating an organic silicon source into your medium already!

"...leafy green vegetables also provide ample amounts of this nutrient. Other food sources for silicon dioxide include asparagus, Jerusalem artichokes, parsley, sunflower seeds and grain husks, such as from barley, oats, millet and wheat."
(Source: livestrong.com

"Silicon is present in beer in the soluble form of orthosilicic acid (OSA), which yields 50% bioavailability, making beer a major contributor to silicon intake in the Western diet. According to the National Institutes of Health (NIH), dietary silicon (Si), as soluble OSA, may be important for the growth and development of bone and connective tissue, and beer appears to be a major contributor to Si intake. Based on these findings, some studies suggest moderate beer consumption may help fight osteoporosis, a disease of the skeletal system characterized by low bone mass and deterioration of bone tissue.

The researchers examined a variety of raw material samples and found little change in the silicon content of barley during the malting process. The majority of the silicon in barley is in the husk, which is not affected greatly during malting. The malts with the higher silicon contents are pale colored which have less heat stress during the malting process. The darker products, such as the chocolate, roasted barley and black malt, all have substantial roasting and much lower silicon contents than the other malts for reasons that are not yet known. The hop samples analyzed showed surprisingly high levels of silicon with as much as four times more silicon than is found in malt. However, hops are invariably used in a much smaller quantity than is grain. Highly hopped beers, however, would be expected to contain higher silicon levels.

No silicon was picked up from silica hydrogel used to stabilize beer, even after a period of 24 hours and neither is there pick up from diatomaceous earth filter aid.

The study also tested 100 commercial beers for silicon content and categorized the data according to beer style and source. The average silicon content of the beers sampled was 6.4 to 56.5 mg/L.

"Beers containing high levels of malted barley and hops are richest in silicon," concludes Dr. Bamforth. "Wheat contains less silicon than barley because it is the husk of the barley that is rich in this element. While most of the silicon remains in the husk during brewing, significant quantities of silicon nonetheless are extracted into wort and much of this survives into beer."
(Source: science-daily.com)

The debate begins whether or not orthosilicic acid, being soluble and bio-available(usable by humans and animals), is available for plant use.

It may seem crazy, but is it possible to remove the alcohol and other potentially harmful chemical compounds from a beer? Maybe one could apply the remaining product to your soil as an immediately available silicon source...

 

Silicic Acid or Orthosilicic Acid is available for plant uptake.

"Silicon (Si) in a chemically combined form is ubiquitous in nature. The Si content of soils can vary dramatically from <1 to 45 % dry weight (Sommer et al., 2006), and its presence in the form of silicic acid [Si(OH)4] (or its ionized form, Si(OH)3O−, which predominates at pH > 9) allows its uptake by plants. Silicic acid is generally found in soils at concentrations ranging from 0·1 to 0·6 mM (Epstein, 1994) but, to our knowledge, there has been no evidence of the occurrence of biosilicification reactions in the soil. Although not traditionally thought of as an element essential to the life cycle of plants, with the exception of the early-diverging Equisetaceae (Chen and Lewin, 1969), certain algae and diatoms, Si is found in plants at concentrations ranging from 0·1 to 10 % (=103–105 mg kg−1; dry weight basis), an amount equivalent to, or even exceeding, several macronutrients (Epstein, 1994). Plants deprived of Si are often weaker structurally and more prone to abnormalities of growth, development and reproduction and it is the only nutrient which is not detrimental when collected in excess (Epstein, 1999). This Botanical Briefing aims to cover aspects of Si uptake and its role as an alleviator of biotic and abiotic stress, and also to provide insight into how investigations into the surrounding plant cell-wall environment are helping to elucidate the role of chemical influences in the formation of polymeric silica in plants. [‘Si’ is the symbol for the element silicon and is also used as a generic term when the nature of the silicon compound(s) is not being specified. Si(OH)4 is silicic acid, more correctly named orthosilicic acid; it is the fundamental building block of silicas and is itself the simplest silica. Silica is amorphous, hydrated and usually polymerized material produced from Si(OH)4.]"

Si accumulation has been found to a greater extent, but not exclusively, in monocotyledonous plants. Plants of the families Poaceae, Equisetaceae and Cyperaceae show high Si accumulation (>4 % Si), the Cucurbitales, Urticales and Commelinaceae show intermediate Si accumulation (2–4 % Si), while most other species demonstrate little accumulation."

(Source: Oxford Journals)

This article is a must read for anyone interested in Silicon's relationship with plants and soil.

http://m.aob.oxfordjournals.org/content/100/7/1383.full

 

Great question Possum, it's nice to see your interest in the topic!

I am personally transitioning towards organics for educational, environmental, economic, moral and strategic marketing reasons.

I like to create educational and informative conversation, social expression of ideas and information drives creativity.

I also understand there is a lot of misconception surrounding cannabis cultivation, and a lot of debate about various organic techniques. If there are organic farmers who are using potassium silicate when it may not be necessary, why not have that conversation?

People like the stomp around and proclaim that cannabis is an all natural plant and medicine unlike the synthetic pills currently being produced by the pharmaceutical companies. The reality is modern commercial cultivation of any plant, but especially cannabis has a potential to be incredibly taxing on our environment. Consider all of the electricity, water, fertilizers, and waste water that will be used/created. I don't want to find myself managing a 150,000 W indoor garden, or green houses on acreage at the expense of our local and global environment.

The poll is for reference of how popular use is amongst the community, and wether or not people care(should I share the information I am finding).