San José, Costa Rica, since 1956

Fertilizer from the Sea: Ocean Water Feeds Plants

Here’s a hot news item among gardeners in Costa Rica that may help you increase your garden production and reduce your expenses. I’m referring to the unique discovery that seawater in a solution diluted with freshwater can be used as a natural fertilizer for plants and trees.

The oceans on the planet are a storehouse of minerals that have been deposited over millennia by rivers, streams and glaciers, as well as volcanic activity in the ocean floor. This process has been accelerated in the present by the erosion of our agricultural soils and their mineral content as a result of large-scale farming practices.

Studies have demonstrated that the majority of our food today is lacking in minerals, which is linked with the causes of our major health problems.

It was once said that “worn-out soil produces worn-out men and women,” in the work of the late Dr. Maynard Murray, who began researching the use of ocean water and sediments to restore soil fertility in the 1930s.Murray observed that ocean fish and sea mammals were remarkable free of cancerous tumors. Working on this observation, he began to experiment with applying ocean solids to soil before planting a wide variety of grain and food crops.

His results were astounding in terms of the higher percentage of minerals found in these crops, which were also healthier and showed greater resistance to disease. Further experiments demonstrated that animals fed ocean-grown feed were healthier and freer of disease. Later he worked with hydroponics, growing vegetables using diluted ocean water with great success.

Ocean water contains more than 90 minerals and trace minerals essential for life on the planet. For decades we have used a commercial seaweed extract as part of our fertilization program to feed our plants with these ocean minerals, but now it seems that we can go directly to the source: ocean water! Here are the guidelines for safe application of ocean water as a natural fertilizer.


Rule number one. Use only three ounces of seawater to one gallon of freshwater.


Collection. Get your seawater from the cleanest areas possible, far from rivers, shipping lanes and fishing boats.


Application rates. Keep in mind your soil type:

Red clay soil – Once every six months to a year. Clay binds nutrients, so adding to the soil more often could cause toxic overload.

Loamy soil – Once every three months, when little or no clay and good drainage are present.

Sandy soil – Once every two weeks to a

month is the maximum.


Foliar. Spray bimonthly the tops and bottoms of leaves at sunrise or sunset, when the birds are chirping.


Garden. Foliar bimonthly.


Big trees. Sprinkle 5-15 gallons under the tree out to the drip line.


Small trees. Sprinkle 2.5-5 gallons under the tree out to the drip line.


Sick trees. Sprinkle five gallons with 30 ounces of seawater to the roots out to the drip line, with normal foliar feed bimonthly until recovery, then taper back.


Bananas. They love minerals, so you can double the strength and apply according to the directions for your soil type, tapering back if leaf burning occurs, or give them the same as everything else for convenience.


Coconuts. Can take it straight, but application rules still apply for soil type.


House plants. Usually get less sun and can be fertilized less frequently or at the same basic recommended dosage.


Nursery plants. Need the maximum recommended dosage for the plant and soil type.


Transplanting. Spray roots of the tree or fill hole and foliar-feed the leaves once a week for two weeks.


With ocean water, less is more, and in this case very powerful. Gardeners must recognize when plants need nourishment and feed accordingly.

For more information on ocean water as a fertilizer, I’d suggest you read “Sea Energy Agriculture,” by Dr. Maynard Murray, and “Fertility from the Ocean Deep,” by Charles Walters.

A big thanks to Tim Tye for bringing the good news on ocean water to Costa Rica. Tye offers consultations and setups for hydroponic gardens using ocean water, as well as ocean water for your garden. E-mail him at

To read more on using seawater as fertilizer, visit or


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