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26 February 2021

Understanding Kelp
Understanding Kelp

With only a month until spring is officially here, temperatures are starting to warm, snow is beginning to melt, and winter is starting to ease a little. This month, I will be diving into the world of kelp and why more and more growers are using it in their fertilizer programs.

Let me begin by sharing some of my experiences with kelp as a nutritional fertilizer amendment. Kelp has been used for decades in the fertilizer industry, but I began understanding and learning about the true benefits of kelp around 20 years ago. It was a very popular product in the fruit and vegetable world, and during my attendance of the Tulare Ag show in California, I noticed it was a very hot topic amongst the growers there. So I began my research into the effects and properties of kelp products. What was the reason that so many growers continually add kelp into their fertilizer programs and what are some of the results they are seeing?

What is kelp?

Kelp is a plant that is grown in ocean “forests” in cold water usually below 14°C and is a form of algae that resembles a plant. It does not quite have a root system but it sends out shoots into the seafloor which is called a holdfast that allows it to hold onto surfaces. The leaves filter seawater through them and capture the readily available macronutrients and micronutrients. These nutrients are then available to the plants and field crops that the kelp fertilizer is applied to. When a plant takes in these nutrients, they enhance the plant’s immune system (very similar to when we take vitamins). It has been studied and observed that kelp can contain over 70 vitamins and minerals.  In ideal conditions, kelp can grow up to 18 inches per day. Kelp is dependant on light for photosynthesis - so it primarily exists in shallow waters.

"These nutrients are then available to the plants and field crops that the kelp fertilizer is applied to."

As I was working in Baja California, Mexico with some growers there, they were excited to show me how they harvest kelp and dry it for use as a fertilizer. It was very interesting to see this process as once it's dry, they then ground the kelp into a fine powder and added it into their foliar applications. They shared with me that they were seeing less disease pressure in crops ever since they started to use kelp. We had some great discussions around the benefits of using kelp and how it helps to protect the plant. In my work across North America, I have seen kelp used in almost every type of growing from orchards and vineyards to vegetables and cash crops, broad-acre, and on golf courses as well.  The increase in yield is just one of the many benefits of using kelp, and we often see better root development, which in turn enhances nutrient uptake and improves plant reproduction.

Different species of kelp.

There are many species of kelp just like there are of most living things on the planet. Species differ from each other in many ways, they can differentiate in their diet (nutrient absorption) and therefore have differences in the vitamins and minerals they contain when dried. Here, I’ll explain the advantages and special benefits of three species of kelp…


Ascophyllum nodosum would be the most commonly found species of kelp used in plant amendments. It contains very high levels of cytokinins which helps to extend shelf life and increase stress resistance in plants. Independent testing has shown Ascophyllum nodosum to increase yields, improve tolerance to heat, drought, salinity and disease stresses. 

Sargassum is another species of kelp that can be found in some amendments. Sargassum mainly boosts drought resistance and contains a different, but advantageous array of micronutrients.

Lamariria is the least common species of kelp found in amendments but contains levels of high iodine, which has been known to aid in biomass production and increase the antioxidant levels in plants which provides drought and stress resistance. 

Research conducted by Dr. T.L. Senn from The Texas Organic Research Center in the late 50's ' and early 60's has revealed a lot about the advantages of using kelp. Over the course of his career, he accomplished over 40 years of research in this field.

"In recent years the results of scientific research provided evidence that seaweeds contain more than 70 micro-elements and that the representation in these plants is considerably higher than it is in terrestrial plants. Of organic substances, marine algae contain, in addition to carbohydrates, proteins, fats, and vitamin substances of a stimulating and antibiotic nature." and, ”when seaweed extracts are used at the recommended times and rates it will supply the amounts of iron, zinc, copper, molybdenum, cobalt, boron, manganese, and magnesium that most crops require” and, "Reports that seaweed releases unavailable minerals from the soil have been made.  Micronutrients have many functions in crop plant growth and development. The amount and availability of micronutrients will vary with soil types and the demand by different crops. Even though the amounts required by plants are small, the micronutrients are just as essential as the nitrogen, phosphorus, and potassium, and in some areas even more so. .....Micronutrients are (also) necessary for plants in times of plant stress, such as flowering, maturing, and during periods of drought.”

[Senn., Dr. T.L. 06/01/1987. Seaweed and Plant Growth.]

We have found that using kelp on any and every plant as it grows will improve its immune system and resistance to environmental stressors. Our kelp products are 100% water-soluble and are very easy to use. They have worked well with growers that have applied it with a backpack sprayer all the way up to a full-size field sprayer and even with helicopters or airplanes. There is no growing operation too small or too big to add kelp to their fertilizer program. Graeme Sait, CEO of Nutri-Tech Solutions Australia discusses the significant vitamin portion in kelp includingvitamin B and vitamin C. Research has shown that plants require vitamins just like animals and humans. Vitamin C protects plants from disease, and eight of the vitamin B group are now recognized as growth promotants in plants.

As you plan your upcoming season of growing make sure that you add kelp into your program and let your plants reap the benefits of this excellent fertilizer. As always, I am here to help and answer any questions you might have as you start to plan for the nearing spring.



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