Soluble Potash (K2O): 20%
Derived From: Fruit Rind Ash
Information regarding the contents and levels of metals in this product is available on the internet at:

Due to the fact that soil, weather, and crop conditions may vary, Ferticell Inc. makes no guarantees or warranties, whether expressed or implied concerning the use of this product. The user of this products takes full responsibility and assumes all risks of usage or handling of this product, despite whether applications instructions were followed or not.

Organic Liquid Potassium Fertilizer

Pro K™ 0-0-20: Organic Liquid Potassium Fertilizer for Crop Production

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As an essential nutrient for plant growth, Potassium availability is critical for optimal plant growth. Many US soils with adequate organic matter can supply some, if not all potassium for crop production. Although when soil K supply is less than optimal, an organic liquid potassium fertilizer program is required, with no better alternative than Pro K™ 0-0-20.

Understanding Pro K™

Pro K™ is a 20%, fully soluble liquid organic potassium fertilizer for crop production. With the lowest published application rates with all crops and most soil conditions, Pro K™ is the highest efficiency potassium and is approved for organic use in over 40 states across the US.

The most unique, and relevant feature of Pro K™ is its plant derivation. As a complete plant-derived organic potassium, Pro K™ stands alone in commercial agriculture as a productive, highly soluble liquid potassium source and is an excellent tank-mix partner that is more efficient than other potassium sources. By design, this opens the grower’s options for both application availability and timing of sprays.

Showing a tremendous result in a variety of crops, Pro K™ 0-0-20 brings an increased yield and quality to market with applications starting after bloom. For wine grapes, essential applications of potassium from Pro K around veraison increase color, Brix, and sugar content. Adding 1 quart to herbicide or SOP sprays provide an added plant-derived immediate uptake of potassium when it’s needed most.

Fruits accumulate large amounts of K, so leaf symptoms are more likely and most severe as fruit approaches maturity during heavy crop years (Hanson, 1996)

Things to Remember about Potassium

Knowing what potassium is removed by crops and knowing its source can help in the development of potassium management programs, as well as considering the use of non-altered potassium that will provide efficiencies and a better yield. Applied as a corrective spray to correct plant K deficiencies; Pro K™ 0-0-20 will not increase soil potassium levels. With Calcium, K enhances the strength of cell walls, allowing for less leakage and less disease risk.

 Plants and crops can achieve their genetic potential with a balance in metabolic energy and nutritional quality of soils through biofortification. K+ performance in all crops is crucial and known natural plant beneficial materials like Universal™ should be considered in fertilizer programs. Potassium functions as the guard cell of the stomata during transpiration. Plants lose more than 90% of their water through transpiration, making water uptake essential.

Pro K™ 0-0-20 Fertilizer for Crop Production

Limiting Factors to Potassium Fertilizers

  • Potassium Sulfate, K 2 SO 4 will have S as a mineral component then must be solubilized to “free” up a K molecule.
  • Potassium Nitrate, KNO 3 will have Nitrates and may be an alteration to rhizosphere pH or interfere with K uptake.
  • Potassium Chloride, KCl with its high salt index and the Chloride that must be dissipated or gassed-off.
  • Potassium Hydroxide, KOH has a very high pH.

Cannabis & Potassium

During flowering, marijuana requires additional potassium, either concurrently with or immediately after lowering nitrogen and phosphorus levels to trigger the transition from vegetative growth to flower buds.

A potassium deficiency in Cannabis may appear like a lack of nitrogen or phosphorus, as both conditions result in yellowing and dying of the lower leaves. Potassium can also be inhibited by high levels of sodium (Na) in soils. The condition is distinguished by the way it begins at the leaf edge or margin, at its worst, new leaves are reduced in size, and flower buds do not fatten.

Pro K™ 0-0-20

Potassium in Potatoes

In university studies, potassium has been identified as a vital nutrient in the production of top-quality potatoes as they require substantial quantities of K. Among all nutrients, potassium is the most readily absorbed by potato plants. As much as 280 lbs. of potassium per acre is removed by a 500-cwt crop. Future and current crops will suffer from a lack of quality and uniformity in their yield, specific gravity, storage capacity, and increased external defects if that nutrient is not replenished.
Potassium plays an important role in controlling a plant's water intake and ensuring plants can withstand drought conditions. Additionally, potassium plays a key role in the turgidity of plant cells

as well as the movement and conversion of sugar into starch within the tuber. Besides increasing potato yields, potassium is also useful in improving crop quality because blackspot bruising is reduced, specific gravity is increased, and chip and fry colors are improved.

A Comparison of Sulfate of Potash and Pro K™


Sulfate of Potash (SOP) has been our only option for organic potassium fertilizer for many years. When looking at the salt contents in SOP and Pro K™ 0-0-20, because of the fruit rind ash derivation, the salts present in each application are higher with SOP. This is because traditionally, SOP has an up to 18% sulfur content. This may limit rates for SOP in many situations and can add to anaerobic soil conditions, unlike Pro K™.
Another disadvantage of potassium sulfate is its price per acre. Sulfate of potash is about 40 to 50 percent more expensive per acre than Pro K™ 0-0-20. In a recent leachate study to pit Pro K™ at just 1 gallon per acre against Sulfate of Potash, at 100 lbs. At 10 days, Pro K™ tested at 0.6 ppm less than SOP 0-0-50. Also noted were reductions in sodium and sulfur. Due to its efficiency, Pro K™ 0-0-20 uses significantly less material compared to traditional applications of sulfate of potash.

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  • An SOP limiting factor is solubility for spray solutions above 5% unless using powdered material unlike Pro K™, is 100% water-soluble for spray or fertigation applications and a farmer-friendly liquid
  • The very light release rate of coated K materials makes it difficult to see immediate corrections in plants and/or fruit that require high application rates. With Pro K™ you can often see results in as little as 24-48 hours
  • The sulfur in SOP is 18%, which may restrict rates in several cases where the sulfur can contribute to anaerobic soil conditions.
  • It is recommended not to apply K to soils with concentrations over 25-40 ppm and always know the amount of potassium in the water source (20-40 ppm).

Potassium Chloride Limiting Factors

The biggest disadvantage of KCl is its chloride content, potassium chloride has an extremely high salt index at 116. Because some crops like potatoes, tobacco, almonds, grapes, tomatoes, cucumbers, strawberries, walnuts, and citrus are sensitive to chloride, Pro K™ 0-0-20 is often preferred over potassium chloride. Crop sensitivities are highly dependent on growing conditions. Soil salinity and salinity and chloride in the irrigation water can also play a role.

The microbes that convert ammonia in the soil to nitrates can be limited by chlorides in the soil, but Pro K™ has none of that baggage, making it a microbe-supporting nutrient. Furthermore, if MOP is added to soils already rich in chlorides, toxicity may occur. In the case of chloride-sensitive crops or chloride-rich soils, Pro K™ 0-0-20 provides an optimal solution since it is significantly lower in chlorides.

Pro-K 2.5 gallon pallet

    Potassium chloride use may present a risk, based on factors such as:

    1. Irrigation water ECw (a measure of salinity) and chemical composition.
    2. Timing of fertilizer applications in relation to planting or growth of a crop during the rainy season.
    3. Amount of rainfall over a growing season
    4. Insufficient irrigation or irrigation combined with below-average rainfall for crops.
    5. The application rate of potassium and if it will be split into more than one application 

    Benefits of Pro K™ 0-0-20

    • Excellent plant absorption rate
    • Rapid uptake through the leaf
    • Ideal where soil application is a limiting factor
    • Extremely phloem mobile within the plant
    • Easy to handle, consistent liquid solution
    • Plant-derived organic potassium
    • Works for both foliar and soil applications
    • Provides a near-immediate plant response
    • No application risk of phytotoxicity
    • Cannot tie up in soils because of molecular derivation
    • Non-salt-contributor and does not contain chlorides
    • Works on all plant life in all stages
    • Instantaneous delivery of key nutrients
    • Known to improve drought resistance

    Product Profile

    Application Rates

    1 quart–2 gal/acre. For best results include Microelements™ in the tank mix.


    Application timing is dependent on crop, time of the season, and desired result



    Color & Form

    Brown liquid


    Compatible with most agriculture liquid fertilizers and pesticides, however, seek professional advice prior to tank mixing.


    Keep sealed in original container. Store in frost-free, dry conditions out of direct sunlight, above 5°C and below 30°C

    Pro K™ FAQ

    What is an appropriate indoor rate/gal of water when using Pro K™?

    5-30 ml per gallon depending on treatments per month.

    How much Pro K™ should I use in foliar sprays? (gal/acre)

    1-4 quarts per gallon depending on need. Consult your agronomist for specific rates and frequencies.

    Are there products I shouldn’t mix with Pro K™?
    While compatible with most products, Iron (Fe) products may not want to be combined since Fe is trivalent. As always you should perform a jar test to be sure.
    How many gallons come on a pallet?
    240 gallons – 5-gal container | 180 gal – 2.5-gal container | 80, 170 & 275 gal IBC Totes