Benefits of organic liquid potassium applications
Discover the benefits of organic liquid potassium fertilizers for crops like tomatoes, almonds, and grapes. Learn how potassium boosts fruit size, plant health, and stress resistance with TRUE Organic’s high-performing products: TRUE 2-0-8 and TRUE Bio K 1-0-7.
Roles of potassium in the plant
As spring progresses and we approach the beginning of summer, the need for potassium increases in most crop species. For many of the important California crops such as almond, grape, citrus, pistachio, and tomato, potassium has a higher uptake rate than any of the plant essential nutrients, including nitrogen. Fruit development is typically the period of maximum potassium uptake. The roles of potassium in the plant promote greater fruit size and quality, while improving plant defense against pest attack and abiotic stresses.
Adapted from nutrientsforlife.org
The Four Key Roles Of Potassium in all plant species
⚡
Energy Production & Utilization
Potassium is essential for photosynthesis. It also activates enzymes involved in respiration and starch formation. Potassium is also necessary for the movement of sugars throughout the plant via the phloem. K-deficient plants often have lower soluble solids in fruit at harvest.
💪
protein formation
Potassium is essential in the nitrogen metabolism process, including the activation of enzymes involved in protein formation.
💧
regulation of water in plant tissues
Potassium is the primary regulator of cell osmotic status. This impacts the movement of water in and out of different parts of the plant. This effects cell expansion, fruit size, stem and root growth, stomatal functioning, and phototropism (movement towards light).
🛡️
Plant Defense against pests and abiotic stress
Potassium deficient plants are more susceptible to a variety of pests including fungal and bacterial pathogens, insects, mites, and nematodes. Potassium is also critical for enabling plants to tolerate abiotic stresses such as heat, cold, and salinity.
Utilizing liquid organic potassium fertilizers
In most soils, only ~2% of total potassium is available to the plant in either the soil solution, or on the exchangeable sites of the soil particles. To supplement plant available potassium, there are a variety of different potassium sources available to organic growers. Most commonly, organic growers rely on manures and composts to supply potassium. This can be a very effective and economical approach, but there are situations where supplemental liquid potassium applications may be beneficial. Lighter soils with lower cation exchange capacity may lose substantial amounts of soluble potassium via leaching. In soils composed of K-fixing clays such as vermiculite, much of the available potassium may get trapped between the clay layers and become inaccessible to the plant. Additionally, if fruit/nut set is greater than anticipated, the base fertility program may have inadequate potassium supply to feed this heavier crop. In these situations, liquid potassium fertilizers allow growers to make targeted applications directly to the root zone of the crop during periods of peak demand.
liquid potassium options
-At True Organic Products, we produce a variety of organic liquid fertilizers with potassium. Our two highest K analysis liquids are TRUE 2-0-8 and TRUE Bio-K 1-0-7. TRUE 2-0-8 is our most economical liquid potassium per unit K. It contains high levels of reduced sugar molasses, which is a plant-derived source of potassium. This molasses is also rich in labile organic carbon making it an excellent food source for beneficial soil microbes. It also contains solution grade sulfate of potash, a low salt index potassium source. Additionally, TRUE 2-0-8 contains fish solubles, an ingredient rich in organic nitrogen as well as heat-tolerant beneficial bacteria that can colonize the root-zone of the crop.
TRUE Bio-K 1-0-7 also contains reduced sugar molasses, sulfate of potash, and fish solubles. But it also brings some potent biostimulant activity from 2% humic acid content. Humic acids have been shown to have a variety of different soil and plant health benefits including stimulating root growth, buffering the negative effects of salts, and increasing uptake of plant nutrients such as potassium. Other biostimulant ingredients in TRUE Bio-K include seaweed extract and soy protein hydrolysate, both of which can reduce abiotic stress, giving them an excellent synergy with potassium applications.
While TRUE 2-0-8 and TRUE Bio-K 1-0-7 have proven to be excellent potassium sources for certified organic growers, they also have a great fit in conventional systems. The high levels of labile carbon and the beneficial bacterial species found in these products can be especially advantageous in conventional soils where soil biological activity tends to be lower. Many conventional liquid potassium products have high salt indices and can have negative effects on beneficial soil microbes. Replacing some of these conventional potassium materials with organic liquid potassium sources can counteract these detrimental effects on soil biology.
For More Information:
To learn more about our liquid potassium products – or any of our other offerings – please reach out to your local TRUE Organic representative or contact us using the form below.
Johnny Peck
Jeff DeLaGuerra
jdelaguerra@true.ag
Ian Humrick
ihumrick@true.ag
Andrew Pedersen
apedersen@true.ag
"*" indicates required fields
© 2025 True Organic Products | View Website | Buy True Organic Products