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Foliar Feeding with Kelp


Controlling diseases on an affected plant by spraying various products to nullify the effects of a pathogen, mildew, fungus & scab is an accepted practice all over the world. Many still run to the nursery to purchase fungicides and other products when we see signs of an ill plant. An interesting note to this method of disease control is that it is known as chemotherapy.

But why not also feed them this way? Why not spray them with seaweed/kelp extract? Those who have read my previous articles or attended my workshops have heard me speak of the benefits of foliar feeding liquid seaweed/kelp extract. By spraying the foliage with liquid seaweed extract, also known as liquid kelp extract, you are introducing substances into the plant that will make it stronger, healthier and increase it’s resistance to sap sucking pests and diseases.

Although it isn’t known yet why kelp products give some kind of biological control over many plant diseases, busy researchers will soon tell us why. I know that my plants when foliar fed with liquid kelp extract develop a resistance to many diseases and pests. They become much stronger. When I apply it as a foliar feed I also reduce the incidence of aphid damage, mildew and fungus. This can be important for rose growers.

When liquid kelp extract is sprayed on the plant the minerals and nutrients are absorbed by the leaves and go into the sap of the plant. From a quantity of product standpoint, this seems to be more cost effective than putting lots of composted or granular kelp into the soil, because you use much less product when spraying. However, I am not saying that the plants don’t need nourishment at the root zone and I also include kelp meal as an amendment when re-building my soil. I just can’t afford to apply it in large quantities as a farmer near the sea might.

It is known that soils high in organic materials are home to soil fungii and bacteria (microbes) that are known to produce natural antibiotics. These natural antibiotics hold down the population of plant pathogens (the bad guys). When these antibiotics are produced in sufficient quantities, from a soil rich in organics, they enter the plant through the roots and help it resist disease. Researchers think that composted kelp added to the organics in the soil could substantially increase this process of making natural antibiotics.

Many gardeners, farmers and professional growers near the sea continue to depend on kelp and kelp products. With or without research, they know that when kelp is applied they have better plants. This may be one of the reasons New Jersey is called the Garden State. (Greensand, another favorite product of mine, is mined off the New Jersey shore.)

It is important to know that kelp contains all known trace elements in a form acceptable to plants. Acceptable is the magic word here. I have written about the wonders of using liquid kelp as a foliar feed in my book on growing tomatoes. In addition to using it on a frequent schedule, the first thing I do when I see a plant, tomato or otherwise, that shows a deficiency, or signs of disease, is to spray it with a solution of liquid kelp extract. Many times the improvement can be seen within hours .I have always seen an improvement and many times complete restoration of the plant. .COOL ! . Other issues may be going on in the soil or plant that I might not be aware of, however, these conditions can be dealt with if the plant returns to ill health.

It is also possible that seaweed sprays stimulate metabolic processes in the leaves, this helps the plant use leaf-locked nutrients. It’s known that trace elements taken in by the roots can be immobilized, or locked-up, in the leaf tissue. Because a considerable proportion of photosynthesis is carried out by bacteria at the leaf surface researchers are studying the effects of spraying leaves with liquid kelp extract. They feel this may feed and stimulate the leaves, which would increase the rate of photosynthesis. This is important in our short daylight hours in the desert, and in the short summer areas around the world; as increased photosynthesis means faster growth.

TIP: When mixing liquid kelp extract into water for foliar feeding houseplants don’t use reverse osmosis water, pure water nor bottled water as these will leave mineral spots on the leaves, use distilled water as the minerals have been removed. In the garden I use the water from the tap. Spray the plant until the kelp solution runs off the leaves. It’s best to do this in the morning when the leaves stoma are open (stoma are like the pores in our skin). With the stoma open the plant is able to take up more nutrients. Also, in the mornings the kelp solution tends to remain wet on the leaves for a longer period of time. The moisture will evaporate quickly when the sun hits the leaves and as the day becomes warmer.

It’s my understanding that the name seaweed and kelp can be interchangeable depending on where and from whom you learned to speak. I grew up in Chicago and my feet would tangle in the seaweed in Lake Michigan. While fishing the Captain would refer to the kelp beds. In both places I tried to speak like the natives. (Yes, I can talk like a sailor and swim like a fish.)

As of this date I have placed kelp, in a dry and water-soluble form, on my web site under products. I call it “Amazing Kelp.” I can’t think of a better name. And it’s cheap, , , 5 ounces makes 64 gallons of foliar spray. Make it up and give a gallon to 63 friends as a holiday present, you will be remembered and Las Vegas will be blooming, lush and green.

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