AgSil 16H Bio-nutrient potassium silicate

AgSil® 16H is a soluble form of potassium silicate providing the plant a 100% available source of silicon and potassium that are essential for optimum plant growth and health. AgSil 16H hydrous potassium silicate powder is our flagship product at We have stocked it since we started the website back in 2010. AgSil 16H is the most concentrated plant available silicon fertilizer on the market.

Certis USA is now distributing the entire AgSil Bio-nutrient line nation wide, which includes AgSil 21 and AgSil 25 liquid potassium silicate concentrates. AgSil 25 is also labeled as Sil-Matrix and sold as an NOP compliant and OMRI listed bio-pesticide.

AgSil products are your bionutrient sources for silicon and potassium.

Crops treated with AgSil products:

  • Are more resistant to mineral stress
  • Experience less climate stress
  • Have improved strength
  • Show increased growth and yield has the following products available:

  • AgSil® 16H

AgSil 16H potassium silicate
Buy AgSil 16h NOW!
  • AgSil® 25/Sil-Matrix

    Sil-Matrix aqueous potassium silicate
    Buy Sil-Matrix NOW!

AgSil helps plants to resist toxicity from phosphorous, manganese, aluminum and iron and increases tolerance to salt. AgSil also aids in resistance to drought by reducing water loss, and in some cases it may increase growth and yield.

Application of AgSil® improves leaf erectness, reduces susceptibility to lodging in grasses and improves photosynthesis efficiency. For turf, this can result in faster, healthier greens and athletic fields. Row crops, vine crops, ornamentals and hydroponically grown plants can all benefit from potassium silicate supplementation.


Calcium Nitrate Fertilizer

Buy Calcium Nitrate fertilizer
Buy Calcium Nitrate NOW


At we carry two high quality, fully water soluble calcium nitrate fertilizers.

  • YaraLiva Greenhouse/Solution Grade 15.5-0-0 with 19% soluble calcium is a hydrated calcium ammonium nitrate with 1.1% ammonium content.

  • Haifa Cal PRIME 17-0-0 with 23.5% soluble calcium is anhydrous calcium nitrate with a low 0.3% ammonium content.

Both products are free of chloride and sodium. They dissolve easily in water providing immediately available nitrogen and calcium to plants. Calcium nitrate is ideal for all irrigation, fertigation and precision fertilization systems including hydroponics. In hydroponics, calcium nitrate is commonly included in the ‘A’ fertilizer concentrate along with potassium nitrate and chelated iron compounds. Because of its calcium content, calcium nitrate is incompatible in solution with phosphorus and sulfate containing fertilizers. So to avoid precipitation in the concentrated solutions, always keep calcium separate from phosphorous and sulfur.

Calcium is a “quality nutrient” that enhances yield quality and prolongs vegetable and fruit shelf life. As the mobility of calcium in the plant is limited, it has to be supplied continuously throughout the growth season to keep adequate levels in the plant tissues and to ensure proper development.

Calcium in the plant

Calcium is essential for the building of cell walls. Poor calcium supply interferes with this important function, resulting in distorted growth and deformation of root tips, young leaves, and shoot tips. In addition weaker cells are more susceptible to biotic attacks. Calcium is also involved in enzymatic reactions and in the coordination of inter-cellular processes.

Calcium deficiency

Calcium deficiency is usually shown as localized rot of tissues, and a consequent growth inhibition. Typical symptoms include leaf deformation, leaf tip burn and root tip burn. Calcium deficiency also reduces quality of the harvest, and shortens shelf life.

Haifa Cal Prime concentrated calcium nitrate fertilizer
Haifa Cal PRIME Now in stock at!




3D Soluble Fish Hydrolysate is a completely soluble organic nitrogen source. Highly bio-available in the soil and as a spray on plant foliage. Guaranteed greater than 80% amino acid content from low temperature enzymatic digestion of food grade sardines fish protein. Spray dried into a fully water soluble powder for easy distribution and shipping. Very stable in storage for a long shelf life. Mild fish odor.


Currently offering 1, 3, 15 pound re-close-able plastic jars or buckets of 3D SOLUBLE FISH FERTILIZER for Home and Market gardeners. For large Agricultural needs it comes in 45 pound bags, stacked 45 bags per pallet. Nation wide shipping available.

Buy 3D Soluble Fish Fertilizer Online now
Buy 3D Soluble Fish Fertilizer Online now

Nitrogen is commonly the most limiting nutrient in high yield production systems. Uses this afford-ably priced high-quality soluble organic nitrogen to improve your bottom line.

Humic and Fulvic acid fertilizer testing and labeling, AAPFCO approved method.

Humic and Fulvic acid plant and soil amendments.

What are humic and fulvic acid?

The Association of American Plant Food Control Officials (AAPFCO) define them as follows:

Humic Substances – the major organic constituents of soil organic matter and the aquatic environment, consisting of complex heterogeneous mixtures of carbon-based substances formed by biochemical reactions during the decay and transformation of plant and microbial remains. They are primarily composed of three main fractions, called humic acids, fulvic acids, and humin, which are operationally defined by their solubility in dilute alkali and acid solutions. High concentrations of humic substances are commercially harvested from terrestrial deposits of Leonardite, oxidized lignite, oxidized sub-bituminous coals, humalite, carbonaceous shales, peat, and sapropel.

Humic Acids – the portions of the alkali extracted
humic substances that are insoluble in strongly acidic
solution. They will precipitate from the alkali extract
in acid solutions of pH 2 or less. They can be used as
either soil amendments, foliar applications, or blended
with liquid fertilizers.

Fulvic Acid Fraction – the portion of humic substances that are soluble in bothalkali and acid aqueous solutions.
Hydrophobic Fulvic Acids – are the portions of humic substances that are soluble in both alkali and acidic aqueous solutions that are separated from non-humic aqueous substances in the fulvic acid fraction by selective adsorption onto a nonionic macroporous acrylic ester resin of moderate polarity i.e. DAX-8 resin, at low pH.
Recently the American Association Of Plant Food Chemist Officials (AAPFCO) has approved a testing method to determine the fulvic acid fraction of plant and soil amendments for the purposes of labeling.
“The analytical procedure developed jointly by the Humic Products Trade Association (HPTA) and the International Humic Substances Society (IHSS) has been approved by AAPFCO as the only officially recognized procedure for the analysis of humic acids and a specific category of fulvic acids. The procedure has been published in theJournal of AOAC International, a peer reviewed scientific journal, and is currently being reviewed by the International Organization for Standardization (ISO) as a possible international analytical standard.” Lawrence Mayhew

The market is saturated with products claiming to have high concentration of either humic or fulvic acid. But I have not seen many products with label claims that have used this new method for the quantification of the humic or fulvic content. The individual state regulatory agency’s are slowly adopting the new method as the required method for labeling claims. I recommend you contact the manufacturer of your humic and fulvic acid products and urge them to lead the way.

Ferti-Organic Soluble Fulvic Acid analysis IHSS-HPTA Lamar method


Comparison of Plant Available Silicon (PAS) in several different fertilizer sources.

Comparison of Plant Available Silicon in fertilizer sources.

Comparison of Plant Available Silicon in fertilizer sources.
Manufacturer Fertilizer name

(common name)

Total Silicon % Soluble Silicon (Si) %

Plant Available Silicon

JAOAC, Vol. #96, #2, 2013

PQ Corp. AgSil 16H

(potassium silicate powder)

24.6% 8.54%
PQ Corp. AgSil 25 – Sil-MATRIX

(potassium silicate liquid)

9.7% 7.6%
SioTex Corp. Grow-Sil

(99.9% SiO2 pure biogenic silica)

46.7% 6.28%
Vanderbilt Minerals VANSIL W10

(natural Wollastonite)

24.2% 3.6%
PQ Corp AgSil 16H stock solution

(560 grams AgSil 16H in one gallon RO water)

~3.34% 3.25%
Harsco Metals llc AgrowSil

(calcium/magnesium silicate blend, stainless steel slag by-product)

12% 2.2%
Harsco Metals llc Crossover

(calcium/magnesium silicate blend, stainless steel by-product)

11.3% 1.9%
Plant Science Concepts

OSA 28

(PEG 400 stabilized silicic acid)

2.09% 1.06%
Mills Nutrients


(stabilized silicic acid)

NA 0.94%

Power Si

(PEG 400 stabilized silicic acid)

1.71% 0.88%


(PEG 400 stabilized silicic acid)

1.61% 0.85%
Loveland Products

SST 28%

(stabilized silica technology)

13% 0.44%

Fossil Shell Flour

(freshwater diatomaceous earth powder)

~42% 0.23%


Total silicon taken directly from the individual fertilizer’s label, or calculated from the labeled SiO2 value. Plant available silicon determined by the American Association of Plant Food Control Officials (AAPFCO) approved method.

Silicon Labeling – The format below should be used for guaranteeing Soluble Silicon (Si) in a dry or liquid fertilizer. The method for Soluble Silicon (Si) is in the Journal of AOAC International, Volume 96, Number 2, 2013, pp 251-259. At this time the method is valid for dry fertilizer and will give a slightly lower number for liquids, but liquids should be analyzed by this method until a method is validated for liquids.   link to source

This method is detailed by Sebastian et al. in the Journal of AOAC International Vol. 96, No. 2, 2013.

A 5-Day Method for Determination of Soluble Silicon Concentrations in Nonliquid Fertilizer Materials Using a Sodium Carbonate-Ammonium Nitrate Extractant Followed by Visible Spectroscopy with Heteropoly Blue Analysis: Single-Laboratory Validation link to source

The values for the Soluble Silicon in the Harsco Metals, and Vanderbilt Minerals products as well as the PQ Corp AgSil 25 are taken directly from the article in the Journal of AOAC International Vol. 96, No. 2, 2013. All other products Soluble Silicon values have been determined by Thornton Labs at the request of a third party. I will display those analysis results below.

AgSil 16H


AgSil 16H stock solution (560 grams AgSil 16H in one gallon RO water)

SioTex corp. Grow-Sil

Grow-sil soluble silicon analysis

Plant Science Concepts, OSA 28

 OSA 28 soluble silicon, plant available silicon

Mills Nutrients, Vitalize

Mills Vitalize soluble silicon, plant available silicon

Fertimaster, Power Si

Power Si soluble silicon, plant available silicon

Aptus, Fasilitor (testing paid for by Plant Science Concepts)

Aptus Fasilitor soluble silicon, plant available silicon

Aptus, Fasilitor (testing paid for by third party product customer)

Aptus Fasilitor (2) soluble silicon, plant available silicon

Loveland Products, SST 28

Loveland SSY 28% stabilized silica technology soluble silicon, plant available silicon

PermaGuard, Fossil Shell Flour, freshwater diatomaceous earth

PermaGuard Fossil Shell Flour freshwater diatomaceous earth soluble silicon, plant available silicon