Salt as Fertilizer

Published 12-31-2016

A famous parable offered by Jesus Christ during his ministry relates to the chemical value of salt as a preservative, a seasoning, and most effectively as a fertilizer. The imagery of salt in its agricultural context provides an exceptional object lesson related to our desire to expand the effectiveness of our personal witness. The application of salt in its role of making food more palatable and in its preservative qualities is also important. In Mark 9:49-50 at Capernaum and in Matthew 5:13 in the Beatitudes, references to salt applied to seasoning and flavoring. But in the Luke 14:34-35 parable, Jesus referred to the value of salt in an agricultural sense as a feltilizer. Perhaps this connection is most important in terms of extending a productive Gospel message.

Scripture contains multiple citations of agricultural practices ranging from soil preparation, planting, and plant growth, to ingathering of the harvest. Object lessons from agriculturalists of Bible times are plentiful. Many are still relevant to the success of modern agriculture. The October 2016 issue of Christianity Today contained an article by Anthony B. Bradley. His article “You are the Manure of the Earth” drew my attention because of its earthy imagery from the barnyard. Having been privileged to grow up within shouting distance of my grandfather’s 150-acre farm in New York State during the middle years of the 20th century, I was able to identify with many gripping images of farm life, some of which were unsavory including the large pile of animal refuse behind the dairy barn when spring arrived.

Chemically, salt, a generic name for a large number of different chemical compounds, including the well-known sodium chloride, has many different functions in the home, on the farm, and in industry. Most people focus on the taste enhancement or preservation properties of salt. Magnesium, potassium, and calcium chlorides have different chemical properties and many of their benefits are longer lasting than sodium. Some chemical changes result in a loss of “saltiness” or “savor” because its desirable properties are altered as the chemical disintegrates.

We return to the “Manure of the Earth” imagery. In Luke 14:34-35 Jesus stated that “unsalty” salt is neither fit for the soil (as fertilizer) nor fit for the manure pile. In the context of the manure pile, we should understand that good salt properly spread on the manure pile preserves the fertilizing properties of manure. Otherwise, the manure would rot or ferment and become useless as fertilizer. Therefore, “unsalty” salt is useless either as fertilizer itself or to enhance the fertilizing properties of the manure because a rotted, fermented, and useless material would result. Anthony B. Bradley concludes this portion of his discussion: “This centuries-tested agricultural understanding of salt fits these passages and the ancient world much better than interpreting the salt as table salt—even if all this talk of fertilizer and manure makes us a bit squeamish.” By no means does this conversation minimize the importance of salt as a a taste-enhancer or preservative.

The December 2016 Christianity Today magazine contained a reply to the “You Are the Manure of the Earth” article. Scientist Steve Sobolik noted that a science background gives insight into understanding scripture. He writes “A ridiculous myth has developed in recent years that science and faith are mutually exclusive; I believe this sentiment is absolutely false, and I think there are hundreds of years of history to prove that. Therefore, I try to use scientific analogies and subjects whenever I can when I talk about my faith with someone, in an effort to tear down that wall.”

Scripture is vibrantly in harmony with the principle that knowledge of the physical and chemical world we inhabit bears witness to spiritual faith principles and affirms the wisdom of God who created all things.


  1. Obadiah on August 28, 2021 at 3:27 pm

    This is a good article, thank you. I’ve been doing research on this parable since it was revealed to me the other night about the fertilizer. It’s enigmatic in a way, how most folks have glossed over this aspect of truth contained in this parable. I searched and searched until I found that same article in CT. It gave me some illumination as well, so I appreciate that you encountered the same process. Very intriguing. I think it’s a vivid explanation of the furthering of Jesus’ progressive message: salt acts as the fertilizer to help us grow, following up the presenting of the beatitudes with the caveat that we are to keep growing, keep moving outward to seek the lost rather than stay in our boxes. I think this is why He went on to explain with regard to light that it, too can be adulterated and if contained cannot be seen properly. I’ll have the article up in a few days on my site.

  2. Thomas on November 11, 2021 at 2:40 pm

    Preparing a sermon on salt and light I researched the effect of salt on plants. Generally it is not a good thing, yet this articel and the metphor that Jesus used says it is good as fertilizer. I am confused.

    • Mindy on December 21, 2022 at 10:24 am

      I find it confusing as well.

    • Mischa on May 18, 2023 at 11:58 am

      The question is, “ how does a plant come into contact with salt in a way that leads to growth and life”? Jesus referred to soil and manure. So, from the ground up? The dark places hidden from the eye, up?

      Salt directly applied to foliage most likely would wilt and kill the plant. But salt taken up through the soil and from manure worked into the soil, does it’s work in the hidden places, giving life from the inside out.

      Jesus said, “have salt IN yourselves”, (Mark 9:50). If one hears the word, as if showered by it, and gives only intellectual assent, but doesn’t receive Christ in his heart; the salt he came into contact with will lead to his destruction. But one who hears the gospel, taking it in through the hidden places of the heart, being transformed by the indwelling Holy Spirit, will grow and bear fruit. (Mark 4:1-9). That plant is given life!

      • Sally Hopkins on February 5, 2024 at 4:36 pm

        Mischa- that’s brilliant insight! Excellent- thank you for sharing that. Also this is a super article from Jum Virkler.
        You have both kick started a bible study now for me all about Salt! Guess I’ll be revisiting Lot’s wife as well as new testament!

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