To begin with off the top, chelation and chelates aren’t a bad thing at all. They have many uses, and have the potential to help us remediate the soil in many environments that have toxic levels of metals. They’re also very effective at doing what they’re designed to do. Chelation involves ionic and molecular bonds and a whole bunch of heady chemistry, but we’re gonna simplify that since that’s not very accessible to the average grower.
In its simplest definition, a chelate is a compound that is bonded to a metal atom at two or more points.
For our purposes, it helps to know where the term comes from. First though, it’s pronounced Key-Late. I have a hard time absorbing info if I’m unsure of the pronunciation and it distracts me.
The word chelate is derived from the Greek word for “claw.” This is a useful visualization of a chelate. The chelate bonds itself to a metal atom in a clawlike fashion. The different chelates are typically called chelate agent(s). For us, a chelate is an agent that bonds to a micronutrient, making the micronutrient more readily available for uptake in plant cells. Most of the micronutrients we use in growing aren’t readily available to the plant in their basic form.
This is because metals like iron and zinc have a positive charge, and the pores on our plants where the metals would enter have a negative charge. The positively charged micronutrients cannot enter through the negatively charged pores. This is where chelates come in. When a chelate bonds to a micronutrient, it surrounds individual ions and gives them a negative or neutral charge, allowing the nutrient to enter through the negatively charged pore and travel into the plant’s tissues. This is what I mean when I say force feeding. It is taking a nutrient that otherwise wouldn’t be able to enter in its current form, and making it supernaturally available to the plant.
In many instances you will see EDTA, DTPA, and/or EDDHA on the sides of your bottles.. Think of them as micronutrient delivery systems for the root zone. Envelopes if you will, that can pass right through the plants barriers and deliver that micronutrient. These synthetic delivery systems are foreign to the plant and so they aren’t absorbed. They’re sent back out into the rhizosphere to collect another micronutrient to drive it back through.
As we can see, chelated nutrients are highly effective at delivering their exact nutrients directly into the plant, regardless of what’s going on. There’s quite a few positives to this.. Micronutrient deficiencies are difficult to overcome with just applying the nutrient to the soil. They get immobilized, washed away, leached out, or generally are in a form incompatible to the plant. If they’re chelated however, all of that becomes irrelevant, the micronutrients are bonded in place and become available to the plant.
Now, for the bad.. EDTA is one of the most popular chelates used in agriculture and unfortunately it is not quickly decomposed by microbes. It is also toxic to them. That’s a one two punch to our food web. We want microbes, we want them badly, and introducing chelates will literally wipe them out.
They will also hang around a long time since they cannot be decomposed quickly, essentially irradiating the area against microbial growth.
Not only are they toxic, they are serving a purpose the plant already can do. The plant can send out its own exudates that act as chelators. These exudates also are what call in the microbes and fungi to do their food web job. Any time we introduce a process already naturally handled we unbalance our web. Nature has been chelating by itself for millennia.
Now for the worse.. those synthetic envelopes(chelates) are nothing more than synthetic salts.. synthetic salts are murderous to our microlife.. as the soil dries out it these salts will devastate our micro populations, and because they take so long to breakdown they continue to make the area around them completely inhospitable to the beneficial life. Organic acids like Humic, fulvic, and ascorbic also aren’t very beneficial to us. They make nutrients available to the roots in unnatural amounts similar to these synthetic chelates, this is again akin to force feeding the plant. We dont want to make decisions for the plant, and since the plant is capable of sending out exudates that naturally chelate nutrients, we have no reason to apply them.
This is a fairly quick and dirty rundown on chelation.. we can expand on any topics any one has any questions on
