The ocean is an incredibly rich source of nutrients. In fact, all-natural elements can be found in the ocean. Some of the largest plants found growing in the ocean, kelp, filter these elements out of the ocean’s waters, and concentrate them in its leaves and roots. " />
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Kelp In Agriculture Part 1

Kelp In Agriculture Part 1

The ocean is an incredibly rich source of nutrients. In fact, all natural elements can be found in the ocean.

Some of the largest plants found growing in the ocean, kelp, filter these elements out of the oceans waters, and concentrate them in its leaves and roots. Using kelp in our gardens allows us to move these concentrations of nutrients from the ocean and into our gardens.

Kelp contains as many as 70 different minerals, enzymes, growth hormones, vitamins, and proteins used by your plants.

Why We Use Kelp In Agriculture

There are a lot of great natural fertilizers out there, but none of them hold a candle to kelp.

Kelp first appeared on earth about 20 million years ago. It requires shallow, nutrient-rich ocean water, and cooler temperatures to thrive. The massive amounts of available nutrients in the water kelp grows in allows it to grow incredibly quickly.

Some species of kelp (such as a Macrocystis spp. and Nereocystis spp.) can grow as much as half a meter per day!

Kelp grows profusely in all areas that meet its requirements for life. It forms large forests covering hundreds of square miles at a time, and can reach lengths of 200m towards the ocean surface. Kelps amazing growth patterns are a direct result of their ability to absorb and concentrate nutrients from the oceans. This means that they’re extremely high in organic nutrients.

Kelp Is Sustainable

Sure, kelp makes for an excellent fertilizer, but is hauling thousands of pounds of the stuff out of the ocean causing damage to the delicate ocean ecosystem?

Thankfully, no! Kelp is a very sustainable product.

Growing kelp for food and fertiliser may also reduce the burden of global warming. University of British Columbia marine ecologist Muhammed Oyinlola says that kelp farming “could remove billions of metric tons of carbon dioxide from the atmosphere”.

Kelp farming operations off the coast of China and Japan produce several million tons of kelp each year.

The History Of Using Kelp In The Garden

Kelp has been used as a fertilizer for thousands of years in coastal areas.

In cooler coastal climates where kelp grows, copious amounts of the seaweed wash up on shore in tangled matts. A few thousand years ago the local farmers started applying the matts of kelp to the soil they planned on using for their crop next year.

It isn’t clear where the idea of using kelp for agriculture started, but the idea has spread like wildfire. Many coastal farmers, use kelp as part of their yearly or bi-yearly soil conditioning efforts.

Adding Kelp To Soil

One of the best uses of kelp is to put it directly into the soil. This strengthens the nutritional profile of the soil, and provides some additional water retentive properties as well.

Trace Minerals In Kelp

Kelp is a great source of nutrition for both plants and humans. It’s benefits towards human nutrition have driven a lot of research projects investigating the chemical makeup of kelp.

This research has found that kelp contains high amounts of iodine, calcium, iron, magnesium, sodium, manganese, and zinc. Plants use these trace minerals to drive different cellular processes in their leaves and roots.

One of the main functions of some of these trace minerals (magnesium, manganese, and potassium) is to drive photosynthesis. Other minerals like zinc are used to produce growth hormones, and sodium is used for energy metabolism. Getting the concentration of these trace minerals right can be challenging. Kelp offers a simple and effective way of ensuring that your plants are getting enough of these minerals on a daily basis to thrive.

Growth Hormones In Kelp

Kelp contains cytokinins and auxins, both of which are plant growth hormones. Cytokinins are used by plants to drive cell division and growth. They increase the thickness of the cell walls, making the plants more resistant to infections and disease.

Auxins regulate the growth of the stems, and boost fruit development.

How To Use Kelp Effectively

There are 3 ways to use kelp in your garden;

  1. As A Mulch Perhaps the oldest method of incorporating kelp into your garden is to use it like a mulch. This is done by collecting the raw, dried sea kelp from a beach, or picking up from your local garden shop, and adding it directly on top of your garden beds. This method is useful for preventing weeds and insects, and will breakdown over time to release its nutrients to your plants.
  2. As A Liquid Fertilizer Kelp can also be bought as a liquid fertiliser. These products vary a lot in quality because once kelp is turned into a liquid, it has a limited shelf life. Manufacturers get around this issue by adding chemical preservatives.
  3. Mixed Into Your Soil Kelp can be chopped up and powdered to add to your garden soil. Here it serves as a broad spectrum fertiliser, and water retention agent. Cre soils include kelp as a key ingredient of the formula. Add to lethargic gardens to give your plants a boost, or use as the primary source of soil for new plants. You can go months before ever needing a top up on the nutrient levels of the soil with the help of kelp.


Kelp has a long history of use in agriculture, and isn’t likely to be going anywhere anytime soon. It offers a potent, broad-spectrum nutritional supplement for your plants, and comes with additional environmental bonuses during its production.

The easiest way to start using kelp is to pick up a good quality soil blend containing kelp. Our Cré line of soils all contain kelp meal as an essential part of the formula. These products are best used during vegetative plant growth, and will supply a large, thriving plant for at least 4 weeks without any added fertilizer.