What's the Function of Potassium (K) in Plants?

Written by Amir Tajer


Posted on November 30 2016

Potassium is a paramount macro-element for overall survival of living things.

It is an abundant mineral macronutrient present in both plant and animals tissues.

It is necessary for the proper functionality of all living cells.

Potassium is relatively abundant in the earth's crust making up to 2.1% by weight.

Potassium is mined in the form of potash (KOH), sylvite (KCl), Carnallite and Langbeinite. It is not found in free nature.


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Why is Potassium Important to Plants?

Green Tomatoes

Potassium is an indispensable constituent for the correct development of plants.

It is important in photosynthesis, in the regulation of plants responses to light through opening and closing of stomata.

Potassium is also important in the biochemical reactions in plants.

Basically, potassium (K) is responsible for many other vital processes such as water and nutrient transportation, protein, and starch synthesis.


Related Post: What's the Role of Manganese and Potassium


How Do Plants Uptake Potassium?

Potted Plants and Potassium

Bio-availability and uptake of K by plants from the soil vary with a number of different factors.

The rate of respiration by plants is largely the determining factor for proper uptake and transport of potassium by plants.

Its uptake is dependent on sufficient energy (ATP).

Potassium plays a vital role in the trans-location of essential nutrients, water, and other substances from the roots through the stem to the leaves.


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It is also made available through fertilizers in the form of K2O. Plant tissues analyze the form in these fertilizers and convert it in a more bio-available form.

It is absorbed in the form of ions- K+.

What is the Function of Potassium in Plants?

Plants Getting Potassium From Soil

Potassium (K) essentially plays a major role in plant physiological processes. Therefore, it is required in large amounts for proper growth and reproduction in plants.

It is considered vital after nitrogen as far as nutrients needed by plants is concerned. It is also termed "the quality nutrient" for its contributing factor in a number of biological and chemical processes in plants.


Related Post: How to Prep Your Garden for Healthy Root Growth


Here is Why Potassium is Important in Plants:

  • Potassium regulates the opening and closing of stomata thus regulating the uptake of CO2 thus enhancing photosynthesis.
  • It triggers activation of important biochemical enzymes for the generation of Adenosine Triphosphate (ATP). ATP provides energy for other chemical and physiological processes such as excretion of waste materials in plants.
  • It plays a role in osmoregulation of water and other salts in plant tissues and cells.
  • Potassium also facilitates protein and starch synthesis in plants.
  • It activates enzymes responsible for specific functions. 

What is Potassium Deficiency in Plants?

Yellow Pansies in Garden

Regardless of its availability from soils, potassium deficiency may occur and might start from the lower leaves and progress towards other vital parts of the plants.

Deficiency might cause abnormalities in plants affecting reproduction and growth. Severity depends on with the type of plant and soil.


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Some potassium deficiency symptoms may include:

  • Chlorosis: May cause yellowing of leaves, the margin of the leaves may fall off, and also lead to shedding and defoliation of the leaves.
  • Stunted growth: Potassium being an important growth catalyst, its deficiency or insufficient might lead to slow growth or poor developed roots and stems.
  • Poor resistance to ecological changes: Reduced availability of potassium will directly result in less fluid circulation and trans-location of nutrients in plants. This will directly make plants susceptible to temperature changes.


What is the Importance of Potassium in Agriculture?

Red radishes home grown gardening

Potassium is important in agriculture and soil gardening. It's used as a constituent in artificial fertilizers.

Potassium fertilizers have been seen to increase crop yields, enhance production of grains rich in starch and protein content of plants.

Additionally, potassium fertilizers may help improve plants immunity to weather changes, diseases, and nematodes.

Potassium is majorly used in hydroponics to improve root growth and enhance drought tolerance. It also enhances the building of cellulose and thus reduces lodging.

Shop Potassium Fertilizers 

To have abundant harvests in every season, don't forget to add a potassium rich fertilizer to your soil. Our line of organic fertilizers, speciality fertilizers, and water-soluble fertilizers offers a solution for every need.

You can shop our selection of potassium fertilizers, below. 




  • Comment author


    Posted by shiney | September 25, 2020
  • Comment author

    Thanks so much wish to be in touch with you every day.

    Posted by Great thanks | June 22, 2020
  • Comment author

    Alma: Thank you for your questions! Fig trees do need potassium, since it flowers like all fruit plants. Potassium is present in certain fertilizers. We actually have quite a few available that you can browse in our online store. Monopotassium Phosphate is always a good choice. You can apply this product every few weeks to your tree. For additional questions or concerns, please reach out to our customer service team via email and we’d be happy to help! Thank you!

    Posted by Greenway Biotech | March 30, 2020
  • Comment author

    Do fig trees need potassium ? How does one purchase potassium ? When and how often should it be applied to the tree.? What products are save to use ?

    Posted by Alma Ortiz | March 30, 2020
  • Comment author

    senait: Hi there, thank you for your question. Potassium is important for fruit setting. This is because it encourages healthy blossoms in flowering plants (all fruit plants). The flowers become the fruit, so if they don’t blossom correctly or they’re sickly, your fruit will not be as healthy as they could be. Potassium is also responsible for ensuring your fruits form to their fullest so they are more robust come harvest time. We hope this helps! Please let us know if you have any other questions or concerns.

    Posted by Greenway Biotech, Inc. | July 14, 2019
  • Comment author

    Is potassium very essential for fruit setting?how?

    Posted by senait | July 14, 2019
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