Pressures from climate change, soil degradation, rising input costs, and keeping pace with an ever-growing human population are bearing down on growers: finding ways to reconcile sustainable growing practices with increasing yields often feel impossible.
One potential solution to this profound dilemma is corn steep liquor, a by-product of the corn wet-milling process that is now being used as an organic fertilizer. While once considered a waste product, corn steep liquor has proven to be a valuable tool for improving soil health, increasing crop productivity, and reducing the damaging environmental effects of synthetic fertilizers.
Deriving value from what was otherwise wasted is one way organic growing methods strive to transform agriculture for the better. In this blog post, we explore the benefits of repurposing corn steep liquor as an organic fertilizer, including its nutritional value, biostimulatory properties, environmental impact, and unique versatility across diverse growing mediums.
What Is Corn Steep Liquor?
Corn steep liquor is a natural by-product produced through the wet-milling of corn—also known as maize—one of humanity’s most productive and ubiquitous crops. This high-yielding grass is also the source of livestock feed, corn starch, corn syrup, biofuel, and biodegradable plastics.
The wet milling process softens corn for grinding and separates the proteins, starches, and sugars. Corn kernels are soaked in wooden tanks for up to two days, during which active fermentation begins to solubilize and break down proteins. At the end of the process, the steep water is filled with amino acids, peptides, minerals, and vitamins.
Historically, corn steep water was considered a valueless waste byproduct. But that is changing. Its nutrient profile and biochemical characteristics make it valuable for livestock feed, antibiotic production, and culturing microorganisms used in biofuel production. When concentrated down into corn steep liquor and dried into a powder, this one-time waste product can also serve as a cost-effective, nutrient-dense, and sustainable organic fertilizer.
Benefits Of Using Corn Steep Liquor As An Organic Fertilizer
Using corn steep liquor as an organic fertilizer is far from widespread. Other organic amendments like animal manure, bone meal, fish emulsion, compost, and kelp meal remain better studied and more accessible. But, through a unique combination of waste repurposing and microbiology, corn steep liquor provides tremendous benefits in ways other fertilizers do not.
Increased Plant Growth And Yields
Corn steep liquor is an excellent source of organic nitrogen in the form of water-soluble amino acids. Unlike many organic sources of nitrogen, like manure or fish emulsion, corn steep liquor-derived fertilizers are versatile and low volume, easily applied as a foliar spray or root drench.
Complementing its high nitrogen content, corn steep liquor is also a source of phosphorus, potassium, and other micronutrients like iron, manganese, and sulfur. It is, in essence, a natural all-purpose fertilizer, shown to increase growth and yields in various crops, from mung beans to peppers to tomatoes.
Improved Microbial Health
Like synthetic fertilizers, corn steep liquor is rich in essential plant nutrients. Unlike synthetic fertilizers, corn steep liquor acts as a biostimulant as well. Its diversity of enzymes, acids, and other bioactive molecules supports the growth of nitrogen-fixing and phosphorus-solubilizing bacteria. Corn steep liquor improves overall microbial diversity in soil and soilless growing mediums, which can enhance plant stress tolerance to pathogens and challenging environmental conditions.
Corn steep liquor also acts as an ideal nutrient source for biodegrading microbes—organisms capable of breaking down hydrocarbon-based pollutants. It can be used to enhance bioremediation efforts in polluted soils.
Reduced Environmental Impact
The environmental benefits of adopting corn steep liquor as an organic fertilizer are twofold. The benefits begin by creating a market for what is still often treated as a waste by-product. The wastewater from wet-milling operations is often flushed into waterways, where its high nutrient content contributes to eutrophication. Algae thrive on the excess nutrients, ultimately suffocating river and marine environments of oxygen and creating massive ecological dead zones.
Using corn steep liquor to fertilize crops puts these nutrients to far better use, “closing the loop” on the waste created by one of the world’s dominant crops. It also would help reduce our reliance on synthetic fertilizers, a source of potent greenhouse gasses, nutrient runoff, and water pollution.
Corn Steep Liquor Vs. Other Organic Fertilizers
Organic farming, and by extension organic fertilizers, represent a more holistic approach to crop nutrition. They are a source of essential nutrients, but their benefits go further than that. Organic fertilizers are often biostimulants and work to improve soil fertility, microbial diversity, and plant stress resistance.
Manure, fish emulsion, blood meal, and bone meal are all effective tools in the organic farming toolkit, and, like corn steep liquor, transform waste byproducts into human sustenance and healthy soils. Unfortunately, many organic inputs are unpleasant to work with, expensive to transport and apply, and unsuitable for soilless growing mediums.
These limitations are in part why Biofuel™ SP, Impello’s all-purpose organic fertilizer, is derived from corn steep liquor. We wanted to create sustainable organic fertilizer that would perform in any growing medium and irrigation system.
How To Use Biofuel™ SP: Impello’s Corn Steep Liquor Organic Fertilizer
Corn steep liquor fertilizers like Biofuel™ SP can be applied as a root drench or foliar spray. We designed Biofuel™ SP to be used alone or to complement both organic and conventional nutrient management programs: it is water soluble and can be mixed with other fertilizers, biological products, and pesticides. As with any new input, we recommend jar testing before mixing and conducting spot applications before treating an entire crop.
Application rates will depend on your growing medium and fertilization program: you can find the application charts for Biofuel™ SP here.
Corn steep liquor remains a novel agricultural amendment. Using it as the base of our all-purpose fertilizer represents Impello’s commitment to innovation, sustainability, and performance. Nature is diverse, resilient, and wastes nothing—principles that also apply to any sustainable agricultural system. By encouraging microbial diversity, improving plant resilience, and recycling waste, organic fertilizers like Biofuel™ SP represent those principles in action.
Chew, K. W., Chia, S. R., Yen, H., Nomanbhay, S., Ho, Y., & Show, P. L. (2019). Transformation of Biomass Waste into Sustainable Organic Fertilizers. Sustainability, 11(8), 2266. https://doi.org/10.3390/su11082266
Hofer, A., Hauer, S., Kroll, P. W., Fricke, J., & Herwig, C. (2018). In-depth characterization of the raw material corn steep liquor and its bioavailability in bioprocesses of Penicillium chrysogenum. Process Biochemistry, 70, 20–28. https://doi.org/10.1016/j.procbio.2018.04.008
Maddipati, P., Atiyeh, H. K., Bellmer, D. D., & Huhnke, R. L. (2011). Ethanol production from syngas by Clostridium strain P11 using corn steep liquor as a nutrient replacement to yeast extract. Bioresource Technology, 102(11), 6494–6501. https://doi.org/10.1016/j.biortech.2011.03.047
Nakano, A., Uehara, Y., & Yamauchi, A. (2001). Establishment of organic fertigation system using CSL (corn steep liquor): Effect of CSL applicaton on tomato (Lycopersicon esculentum Mill.) growth, yield, quality and soil chemical property. Japanese Journal of Soil Science and Plant Nutrition (Japan), 72(4), 505–512. https://agris.fao.org/agris-search/search.do?recordID=JP2001006042
Navarro-Morillo, I., Navarro-Perez, V., Perez-Millan, R., Navarro-León, E., Blasco, B., Cámara-Zapata, J. M., & García-Sánchez, F. (2023). Effects of Root and Foliar Application of Corn Steep Liquor on Pepper Plants: A Physiological, Nutritional, and Morphological Study. Horticulturae, 9(2), 221. https://doi.org/10.3390/horticulturae9020221
Salam, L. B., & Ishaq, A. (2019). Biostimulation potentials of corn steep liquor in enhanced hydrocarbon degradation in chronically polluted soil. 3 Biotech, 9(2). https://doi.org/10.1007/s13205-019-1580-4
Impello Fact Checking Standards
Impello is committed to delivering content that adheres to the highest editorial standards for accuracy, sourcing, and objective analysis. We adhere to the following standards in reviewing our blog articles:
- We have a zero-tolerance policy regarding any level of plagiarism or malicious intent from our writers and contributors.
- All referenced studies and research papers must be from reputable and relevant publications, organizations or government agencies.
- All studies, quotes, and statistics used in a blog article must link to or reference the original source. The article must also clearly indicate why any statistics presented are relevant.
- We confirm the accuracy of all original insights, whether our opinion, a source’s comment, or a third-party source so as not to perpetuate myth or false statements.