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Water Soluble Kelp – Benefits of Using Kelp as Fertilizer


Origins of Kelp Fertilizer

Kelp grows naturally in the sea, however the most popular species is Ascophyllum Nodosum. This type of kelp usually grows in the Atlantic Ocean (mostly in cold waters). It is a type of a seaweed that grows in abundance in most seas, and is often used as a food source.  It typically grows in quite shallow water, and only grows in saltwater.

The most interesting fact about kelp is that it grows in thick canopies and almost looks like a forest when it grows in abundance. Kelp is supposed to grow up to 18 inches a day, and its abundance, and rate of growth makes it an excellent sustainable fertilizer.

How is Kelp Turned into Fertilizer?

  • First of all, kelp is harvested and then washed with fresh water to get rid of excess salt.
  • After washing, the kelp is dried to the point of dehydration, getting rid of any water.
  • Once dry, it is ground up not powder form allowing easy transport.

In order to gauge the value of harvested Kelp for gardening purposes, it is tested for cytokinin levels. These growth harmones are important to ensure cell division, which is key for plant development. Without high levels of cytokinin, kelp would not be much use as a fertilizer.


What is water soluble kelp?

Soluble kelp is basically high grade dried kelp powder that acts as a concentrated fertilizer. As the name suggest, it is then added to water (usually chlorine free).

A typically good kelp wan be mixed at the rate of one tablespoon of kelp per gallon of water.

What is Liquid Kelp Fertilizer?

Liquid kelp is simply the name given to the mix of the dry kelp and water. Kelp is almost always sold as a concentrate powder. Although the recommended dilution is 2.5 oz per 50 gallons of water, you can adjust the dilution level based o the plants and plant life stage, to control the level of nutrients being added to the soil.

Primary Benefits of Kelp

  1. Rapid Root growth rate
  2. Reducing transplant shock by soaking seeds and bubs in kelp
  3. Excellent foliage feed for both indoor and outdoor plants.

Photo by Chris Stenger on Unsplash