Saturday, October 13, 2012

Organic Fertilizers–Part 5–Sea Sources

Ocean Plants and Fish Offer Great Fertilizers

kelp in ocean

From Kelp, we get one of the most nutritious organic fertilizers.  This algae is not the seaweed that washes up on the beach, but a highly sustainable plant that is harvested from the ocean floor.  The kelp regrow within ten days of harvest, giving a fresh harvest that is quite renewable.  
Kelp contains 79 minerals, or micronutrients. The is almost every mineral and trace mineral found in nature. Carbohydrates are available to feed microorganisms in soil when applied as an organic fertilizer.

 kelp plants

Kelp is the most common type of seaweed. It is processed in three different methods.  One is a Kelp Powder.  The fine ground kelp is small enough to be mixed into a solution.  Applied as a foliar spray, kelp powder solution nutrients that can be taken in by the foliage of plants.

kelp powder

Kelp meal is another version of this organic fertilizer source.  Kelp meal is a good source of potassium , with some nitrogen.  Kelp meal is primarily used as a soil conditioner. 

kelp meal

Kelp meal, or seaweed meal, is dried and milled into a powder as shown here. Liquid kelp is yet another form of this product.  Liquid kelp is usually cold processed and has high amounts of growth hormones.  These hormones are readily available to plants.  Liquid kelp can be mixed into water for application. 
liquid kelp seaweed

seaweed   greenSeaweed is divided into three types – green, brown, or red. seaweed  brownseaweed  red

Seaweeds, particularly the green and brown seaweeds, are processed into extracts which are accepted in the horticultural industry to improve plant yields, plant growth, plant health, and the plants have better resistance to insects and diseases. Seaweed extracts are full of macro- and micronutrients.  High in amino acids, and plant growth regulators, seaweed extracts offer a good source of nutrients to benefit plants.


Fish fertilizer is a by-product of the fishing industry.  Most fish that are processed into fertilizers are not fish by-products that come from the food industry, but fish that are specifically used for plants and animals. These are bottom fish that don't make the grade for human consumption.

Like the seaweed, fish fertilizers come in different formulas. Fish powder is ground up, and using heat, produces a water soluble product that is high in nitrogen.

fish powder

Fish meals are ground up carcasses of fish.  The meal is high in nitrogen with an N-P-K of around 10-6-2. Nitrogen aids in the growth of plants, and the phosphorous benefits good root development.  Use fish meal early in the growing season for vegetables and flowers for a slow release benefits for months.

Using a process called hydrolyzing, which uses enzymes, manufacturers omit the use of heat and acids in making a product that is water soluble and high in nitrogen. This product called Liquid fish are less smelly than Fish emulsions. However, the cost is higher.

Fish emulsions are produced from the fluid remains of the fish. A liquid remains and results in a fish concentrate by evaporating this liquid by about half.  The evaporating portion of this process destroys some nutrients but at 5-2-2, fish emulsions are still known for the micronutrient availability.

fish liquid
fish bone mealFish bone Meal is high in calcium                                                  
Alaska Fish Fertilizer is OMRI (C) listed

Ok – here is the conundrum I am facing: Do I close this article now, or do I tell you –as Paul Harvey used to say – the rest of the story?

Fish emulsions and fish meal are made mainly from fish that are not suitable for human consumption.  This ‘trash’ fish often contain toxins.  The Menhaden is a fish that spends time in heavily polluted waters and is a popular fish in production of emulsions.  Heavy metals can be found in these fish. Even some freshwater fish that are not allowed for human food, are used in some fish emulsion processes.

bunkerBunker or Menhaden Fish
fish processingFish Processing

Some fish fertilizer companies do use food grade waste products in addition to non-food fish. This may reduce the impact of the toxins that may be in non-food ingredients

When steam is used in the process, it can be problematic too, especially if the water comes from a municipality that chlorinates it’s water. Since the emulsion is ‘reduced’, the chlorine becomes more concentrated too. High chlorine amounts can harm plants.
If you can't tell from the product label, check on the MSDS, Material Safety Data Sheet for details.  The MSDS will be specific on ingredients and chemicals in the product.

I will be looking for liquid fish made from the enzymes.  This process retains more of the proteins, enzymes, vitamins, and micronutrients than emulsions.
Enzymaticall Digested Hydrolyzed Flquid fish
Peaceful Valley Enzymatic Digested Liquid Fish

Seaweed, kelp, and fish can be excellent fertilizers.  The seaweed and kelp are highly renewable, and the fish by-products offer complete nutrition to plants if they are not loaded with heavy metals.
( I have no financial connection with any of the products I have featured here.)
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