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Lovers and haters of coco coir in organic soil discussion

Klompen

Active member
Years ago I put about 30% coir in an organic soil mix and never wanted to grow without it again. Even this much essentially protects the plant from drowning and gives the mix a good consistency. Also coir has a smell to it that I truly love. I have used coir over and over again with no ill effects. I've also known others who do the same.

On the other hand, there's some who strongly dislike it. Many claim it will release toxic amounts of potassium over time and thus should be avoided. Others just seem to dislike it compared to peat for its relatively low CEC. I personally would not go without a little peat in my mix as well though.

Who loves it? Who hates it? Who has had good experiences with it and who has had bad experiences? Anyone else here reuse organic coco substrates with good experience after good experience? Anyone tried to and failed?
 

J-Icky

Active member
I didn’t use exact measurements when I made my latest soil mix but there is at least 20% coco in it along with peat and ancient forest/humus and topped off with a mix of amendments.
My seed starting mix is 70% promix organic potting soil and 30% coco.

Like the OP I like the texture it gives the soil and the fact that it keeps the peat from over soaking the root zone. I honestly think of it as more of an aeration additive than anything else.
 

Klompen

Active member
Have you reused coco over many grows? I have noticed that having coco in the mix can sometimes mean its good to monitor your pH more carefully than with a totally peat based mix, but as long as I did that I never had serious issues with reusing coco in an organic soil mix.

I know a lot of living soil folks don't like to ever mix up the substrate though; so adding in fresh coir as the old stuff breaks down doesn't jive with their grow style. I believe in strategic mixing, but I do like to keep it somewhat limited.
 

dank.frank

ef.yu.se.ka.e.em
ICMag Donor
Veteran
My personal potting media:

3 gal dirt / earth / topsoil / nursery soil (unfertilized)
1.5 gal coir
2.5 gal peat
3 gal aeration (chunky perlite, lava rock, permatil, etc.)
1 gal EWC

I've been using this mix for about 7-8 years. Posted it publicly for all to use 5 years ago. Have soil based on this mix I've been using consecutively for about 4 seasons.



dank.Frank
 

Microbeman

The Logical Gardener
ICMag Donor
Veteran
Hey Frank. I'm curious if you have run no-till with this or remix/reamend. Good to see you still kicking ole pal.
 

dank.frank

ef.yu.se.ka.e.em
ICMag Donor
Veteran
I use a modified version of this with increased compost amounts (to make more affordable) in raised beds (220 gallons) for vegetables. Have used it for years. I'll add back compost for organic matter to top the beds off, but otherwise, it's a simple re-amend based on crop specifics. Scratch into the top inch and carry on with watering as normal.


Should mention, I use 3 items for aeration amendment. If it was only one or the other, the mix would not be nearly as good. Porosity, tilth and oxygen in the root zone is just as important as what you feed, when it comes to fostering microbial and fungal communities. It would NOT work very well as a no-till media without the 3 part aeration equation because it eventually begin to suffer from soil compaction. Which I suppose could be mitigated with worms, etc. But, if the goal is to build a proper soil out the gate, it's key.




dank.Frank
 
Last edited:

KIS

Active member
Here's what I wrote a while back on the subject. Easier to cut and paste. Can't link the resources, but you can probably find them pretty easily via google but don't want to get into an issue with Frank over posting links.

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This can be a hotly debated topic among growers as to what's the best media for growing plants. In this article, I'll weigh in with my opinion on the subject as there are Pros and Cons to both.

"Sphagnum" is a genus of approximately 120 different species of mosses known as "peat moss." Sphagnum and the peat formed from it do not decay readily because of the phenolic compounds embedded in the moss's cell walls. Peat moss can also acidify its surroundings by taking up cations, such as calcium, magnesium, and potassium, and releasing hydrogen ions. Under the right conditions, peat can accumulate to a depth of many yards. These bogs are slowly building and 80% of the peat moss used in the United States comes from Canada. Approximately .02 percent of the 270 million acres (422,000 square miles) of Canadian peat bog are used for peat moss mining. There are some efforts made to restore peat bogs after peat mining. It is debated as to whether the peat bogs can be restored to their pre-mining condition and how long the process takes. Many peat companies claim this to be a sustainable practice, but that is hotly debated topic depending on where you source your information on the subject.

Pros of Peat Moss:

Free of weed seeds, pests and pathogens.
Can absorb up to 20 times its weight in water.
Contains beneficial microorganisms.
Acidic pH (a "pro" in my opinion because you can add highly alkaline amendments to it).
Contains a variety of elements, especially sulfur, which helps with proper terpene expression.
Excellent habitat for beneficial microorganisms.
Harvested in North America, which reduces the fossil fuel impact to get it to the United States.
Holds 10x to 20x its dry weight in water.
Better C:N ratio than coco coir.
Cation exchange capacity (CEC) of 100-200.
Cons of Peat Moss:

Depletes peat bogs, which requires them to be re-built or sustainably harvested.
Naturally hydrophobic, meaning if allowed to dry out it will be slow to accept water.
Needs to be kept evenly moist for optimal plant growth and health.
Requires hydrating before use.
Coco coir is the natural fibrous material found between the hard, internal shell and the outer coat of a coconut. It is treated before use as a growth medium for plants or fungi by soaking in a calcium buffering solution; most coir sold for growing purposes is pre-treated. Once any remaining salts have been leached out of the coir pith, it and the coir bark become suitable substrates for growing plants.

Pros of Coco Coir:

Coir pH usually runs 6 – 6.7.
"Renewable" resource - byproduct of the coconut industry.
Easier to rewet than peat moss, is not hydrophobic.
Usually cheaper than peat moss.
Different reports list coco as having a water capacity ranging from 8x to 30x it's own weight.
Excellent habitat for microorganisms.
Free of weed seeds, pests, and pathogens.
Breaks down slower than peat due to high lignin content.
Cation Exchange Capacity of 40-60.
Cons of Coco Coir:

High salinity unless properly washed.
Quality can vary depending on batch and source of material.
Higher fossil fuel cost to get the coir to the United States from tropical regions.
Does not contain many trace elements.
Does not contain microorganisms.
Traditionally high in sodium and potassium which can lead to calcium or magnesium deficiencies unless properly treated.
Requires hydrating before use.
Increased incidence of nasobronchial allergy among workers in this industry due to the high amount of dust created.
Some peat in tropical regions is being sprayed with pesticides like neonicotinoids, one of the pesticides most commonly linked to honey bee death.
As you can see, it's not a black and white decision as to which growing media is superior. Personally, I prefer sphagnum peat moss because of the existing microbiology and the fact the pH is acidic, allowing for highly alkaline amendments like biochar and calcium in the form of ag lime and oyster shell flour. I've also had issues in the past with quality control on coco coir and heard horror stories of variability between batches from the same manufacturer containing high salinity. Regardless of what you choose, I hope this article helped you form a more educated opinion on the subject. Happy growing!

Resources:

The Truth About Peat Moss

Does Peat Moss Have A Place In The Ecological Garden?

The Peat Moss Association in Canada

A Comparison of Coconut Coir and Sphagnum Peat as Soil-less Media Components for Plant Growth

Getting to the Coir of the matter

How Coir Is Made

What Your Substrate Is Trying To Tell You

The Importance of Buffering Coco Coir

Nasobronchial Allergy and Pulmonary Function Abnormalities Among Coir Workers of Alappuzha

Philippine Coconut Farmers Warn Over Pesticide Use

Use of Toxic Pesticide on Coconut Trees Assailed
 
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