The Chemistry behind Coco Coir: a (strange) journey from ferts bottle to to buds

Sorry if this has been covered already. If you were to flush your plants improperly with soft water, how do/can you restore the CEC? Do you just need to flush again with a dose of the nutrient solution to restore it? Or do you need to soak the coco?

I have been burned by this a couple of times in mid-late flower, quite literally. I think I let the coco dry out too much, get salt burn, flush (with 0.6ec solution), burn continues, flush again, burn continues, get pissed off and flush with my soft <10ppm water. That finally removes the salts but I think by then I've totally screwed the coco's CEC and get potassium like deficiencies for the remainder of the grow. Which in itself also looks like a continuation of the salt burn.

Nevertheless, I think Cook has triggered a few ah-ha moments for me and coco. Can't wait for the next grow. Thanks again Cook!

au_ said:

Sorry if this has been covered already. If you were to flush your plants improperly with soft water, how do/can you restore the CEC? Do you just need to flush again with a dose of the nutrient solution to restore it? Or do you need to soak the coco?

I have been burned by this a couple of times in mid-late flower, quite literally. I think I let the coco dry out too much, get salt burn, flush (with 0.6ec solution), burn continues, flush again, burn continues, get pissed off and flush with my soft <10ppm water. That finally removes the salts but I think by then I've totally screwed the coco's CEC and get potassium like deficiencies for the remainder of the grow. Which in itself also looks like a continuation of the salt burn.

Nevertheless, I think Cook has triggered a few ah-ha moments for me and coco. Can't wait for the next grow. Thanks again Cook!

Click to expand...

Pictures would be a big plus, but sounds like a CalMag deficiency to me.

Bwanabud said:

Pictures would be a big plus, but sounds like a CalMag deficiency to me.

Click to expand...

Grows are long gone Bwana and I didn't take pics sorry mate

Yeah whatever it was, it spiralled out of control. It actually put me off coco until I found this forum about a month ago. I realised what I was doing wrong and now I'm having another crack at it with some super skunk, ak x ww, budzilla and pineapple chunk. I have veg sorted in coco and will clone/flower until I nail it

good way of explaining

best info thread for coco that i have seen!


thanks for this

au_ said:

Sorry if this has been covered already. If you were to flush your plants improperly with soft water, how do/can you restore the CEC? Do you just need to flush again with a dose of the nutrient solution to restore it? Or do you need to soak the coco?

I have been burned by this a couple of times in mid-late flower, quite literally. I think I let the coco dry out too much, get salt burn, flush (with 0.6ec solution), burn continues, flush again, burn continues, get pissed off and flush with my soft <10ppm water. That finally removes the salts but I think by then I've totally screwed the coco's CEC and get potassium like deficiencies for the remainder of the grow. Which in itself also looks like a continuation of the salt burn.

Nevertheless, I think Cook has triggered a few ah-ha moments for me and coco. Can't wait for the next grow. Thanks again Cook!

Click to expand...

thanks man glad you found it usefull

Anyway consider that, as much strong your nutrient solution can be, it will be very far from being saturated. It'll dissolve salts just like tap water would. Just flush with that. The problem with flushing with just water is some ions bond to colloids better than others so some will just run away with the first runoff will others will be very hard to get washed away, leaving you with a very unbalanced situation and a question mark on your head.

also, nice and slow it's better.

excellent thread! thank you!

delta9nxs said:

excellent thread! thank you!

Click to expand...

You're welcome bro!

Buffering Up: Adjusting the Cation Exchange Capacity in Coco Growing Media

Buffering Up: Adjusting the Cation Exchange Capacity in Coco Growing Media

https://www.joomag.com/magazine/max...6-september-october/0358481001470167087?short

page 36 Maximum Yield Canada | September/October 2016

The widespread use of calcium and magnesium supplements in the indoor gardening industry is an indication that many growers have discovered the cation exchange capacity (CEC) phenomenon in coco media. Growers are observing deficiencies and trying to correct those deficiencies with calcium and magnesium supplements. This article explores why these deficiencies happen and how adjusting the cation exchange capacity, or buffering, the media corrects this problem.

Coco growing media has changed a lot in the last decade or so. Previously, the majority of coco products were washed to an EC of 1 or 1.6, and few products on the market were buffered. Today, the higher-quality coco products are washed multiple times and will have an EC of 0.5 or lower. They will also be buffered in some way or another.

Coco Cation Exchange Capacity

Soil particles and organic matter have negative charges on their surfaces that attract cations. The total of these negative charges are collectively referred to as the CEC. The CEC is significant in growing media because it is a measure of the quantity of nutrients the media is able to hold on to before nutrients start leaching out. Plants are able to access the cations attached to the cation exchange capacity.

Coco often has a CEC in the range of 90-100 meq/100 g of media. The CEC of coco is naturally loaded with potassium (K) and sodium (Na), with little or no calcium (Ca) or magnesium (Mg). These are the four cations that are most important when buffering coco. The goal is to significantly lower the percentage of CEC sites that have K and Na on them and increase the percentage of CEC sites that have Ca and Mg attached. Potassium can be attached to up to 40 per cent of the sites and sodium can be attached to up to around 15 per cent of the sites. This is significant because if 40 per cent of the exchange of un-buffered coco is holding potassium, then that equals 40 meq/100 g of media of the single-charge K molecule.

The 100 g of weight in the above equation is the dry weight of the coco, not the weight of the coco straight out of a bag when it is moist. Hydrated coco should make 12 to 15 litres of coco growing media per kilogram of dry coco and of course 100 g is one-tenth of a kilogram. This does not sound like much, but would be as much as 1.56 g of potassium per 100 g of media. This is a lot of potassium, most of which will be slowly released into the aqueous solution around a plant’s roots. Compare this 1.56 g to 0.22 g of potassium per litre of nutrient solution (which is feeding potassium at 220 ppm, the amount that one would have in a well-balanced feed). If you have a 15-litre pot and give it 3.7 litres of feed per day, you would be feeding about 0.9 g of potassium and the CEC may be holding 15.6 g of potassium. Sodium may be present in up to 0.35 g per 100 g of media. With these numbers, an unbalanced nutrient solution will quickly result, as I explain in more detail below.

Coco Buffering

Buffering coco media is accomplished by exposing the cation exchange to a solution of water with a high concentration of the cations that are desired on the exchange sites—in this case, calcium or calcium and magnesium. Because the cations on the exchange sites are held reasonably tight, washing coco does little to change the makeup of the cations on the exchange sites. The washing will change the EC but not the CEC. CEC sites have a preference for some cations over others. If the cations of Ca, Mg, Na and K are all present in the solution at the same concentration, they will be adsorbed at different levels, with calcium and magnesium being adsorbed at double the rate as they both have a double-positive charge, while potassium and sodium have a single-positive charge (Ca++, Mg++, K+, Na+).

For example, many coco product manufacturers buffer their coco with 8 kg of calcium nitrate per cubic metre of coco. Calcium nitrate has a value of 19 per cent calcium, which equals 1,520 g of Ca with almost no Mg, K or Na if the water is clean. As the process commences, a high concentration of Ca molecules attaches to the media— as each Ca++ molecule is adsorbed, two molecules of K+ or Na+ are released because the Ca has a double-plus charge and K and Na are single-plus charges. In the beginning, the exchange goes very quickly, but as the exchange continues, the concentration of the K and Na molecules released into the solution slows the exchange down and it will eventually come into equilibrium. The buffering process can be done in 10 to 15 minutes—the point at which the exchange slows down enough that the greater exchange is not worth the wait.

Some coco products have been buffered with a higher treatment of Ca and Mg concentration. This creates a lower K and Na percentage on the exchange and adds the benefit of Mg to the CEC. These more advanced buffering processes involve a much greater amount of time, but result in much lower K and Na levels on the exchange. This essentially creates a better coco product from day one, ensuring all of a nutrient mix goes straight to the plant versus amending the coco’s CEC.

What Does This All Mean for the Grower?

As a grower, your goal is to create and use a well-balanced nutrient solution. If you are using an un-buffered coco product, a well-balanced nutrient solution goes into the coco and starts to buffer the coco as well as feed the plants, instead of all of the nutrients going directly to plants. So, the CEC in the coco is exchanging some of the K and Na for Ca and Mg. This exchange is now unbalancing your nutrient solution, increasing the K and Na while decreasing the Ca and Mg. How much unbalancing, you ask? Earlier, I mentioned the coco could have as much as 1.56 g of K and 0.35 g of Na per 100 g of coco. Your nutrient mix is not highly concentrated with Ca and Mg, but it is enough to get some of the K and Na released from the CEC.

About 15 years ago, I was growing roses in coco and we did a weekly chemical analysis of our feed and drain water. The first time we used coco, we noticed the Ca in our drain water was less than 40 ppm (we would have normally expected the Ca to read 100 to 150 ppm in the drain water), and we were feeding Ca at a rate of about 200 ppm. For the next two weeks, we had the same result, so we doubled our Ca to 400 ppm. The analysis of our drain water went up to about 50 ppm of Ca. We watched that for about three weeks and then started feeding Ca at about 500 ppm and still saw very little change in the Ca ppm in our drain water. It took about four months for our drain water Ca analysis to read about 100 ppm. The loss of the Ca and Mg is one thing, but you also get an increase of K and Na. High levels of K will hinder the uptake of Mg by plants. Sodium can negatively impact plant health even at low levels and is toxic to some plants starting at 50 ppm.

The widespread use of calcium and magnesium supplements in the indoor gardening industry is an indication that many have experienced the CEC phenomenon in coco that I am talking about here. The deficiencies are observed and can be corrected to a certain extent with calcium and magnesium supplements, but there are also coco products out there buffered to a higher level, which don’t need the calcium and magnesium supplements.

good info.

good info.

thanks

zeke99 said:

https://www.joomag.com/magazine/max...6-september-october/0358481001470167087?short

page 36 Maximum Yield Canada | September/October 2016

The widespread use of calcium and magnesium supplements in the indoor gardening industry is an indication that many growers have discovered the cation exchange capacity (CEC) phenomenon in coco media. Growers are observing deficiencies and trying to correct those deficiencies with calcium and magnesium supplements. This article explores why these deficiencies happen and how adjusting the cation exchange capacity, or buffering, the media corrects this problem.

Coco growing media has changed a lot in the last decade or so. Previously, the majority of coco products were washed to an EC of 1 or 1.6, and few products on the market were buffered. Today, the higher-quality coco products are washed multiple times and will have an EC of 0.5 or lower. They will also be buffered in some way or another.

Coco Cation Exchange Capacity

Soil particles and organic matter have negative charges on their surfaces that attract cations. The total of these negative charges are collectively referred to as the CEC. The CEC is significant in growing media because it is a measure of the quantity of nutrients the media is able to hold on to before nutrients start leaching out. Plants are able to access the cations attached to the cation exchange capacity.

Coco often has a CEC in the range of 90-100 meq/100 g of media. The CEC of coco is naturally loaded with potassium (K) and sodium (Na), with little or no calcium (Ca) or magnesium (Mg). These are the four cations that are most important when buffering coco. The goal is to significantly lower the percentage of CEC sites that have K and Na on them and increase the percentage of CEC sites that have Ca and Mg attached. Potassium can be attached to up to 40 per cent of the sites and sodium can be attached to up to around 15 per cent of the sites. This is significant because if 40 per cent of the exchange of un-buffered coco is holding potassium, then that equals 40 meq/100 g of media of the single-charge K molecule.

The 100 g of weight in the above equation is the dry weight of the coco, not the weight of the coco straight out of a bag when it is moist. Hydrated coco should make 12 to 15 litres of coco growing media per kilogram of dry coco and of course 100 g is one-tenth of a kilogram. This does not sound like much, but would be as much as 1.56 g of potassium per 100 g of media. This is a lot of potassium, most of which will be slowly released into the aqueous solution around a plant’s roots. Compare this 1.56 g to 0.22 g of potassium per litre of nutrient solution (which is feeding potassium at 220 ppm, the amount that one would have in a well-balanced feed). If you have a 15-litre pot and give it 3.7 litres of feed per day, you would be feeding about 0.9 g of potassium and the CEC may be holding 15.6 g of potassium. Sodium may be present in up to 0.35 g per 100 g of media. With these numbers, an unbalanced nutrient solution will quickly result, as I explain in more detail below.

Coco Buffering

Buffering coco media is accomplished by exposing the cation exchange to a solution of water with a high concentration of the cations that are desired on the exchange sites—in this case, calcium or calcium and magnesium. Because the cations on the exchange sites are held reasonably tight, washing coco does little to change the makeup of the cations on the exchange sites. The washing will change the EC but not the CEC. CEC sites have a preference for some cations over others. If the cations of Ca, Mg, Na and K are all present in the solution at the same concentration, they will be adsorbed at different levels, with calcium and magnesium being adsorbed at double the rate as they both have a double-positive charge, while potassium and sodium have a single-positive charge (Ca++, Mg++, K+, Na+).

For example, many coco product manufacturers buffer their coco with 8 kg of calcium nitrate per cubic metre of coco. Calcium nitrate has a value of 19 per cent calcium, which equals 1,520 g of Ca with almost no Mg, K or Na if the water is clean. As the process commences, a high concentration of Ca molecules attaches to the media— as each Ca++ molecule is adsorbed, two molecules of K+ or Na+ are released because the Ca has a double-plus charge and K and Na are single-plus charges. In the beginning, the exchange goes very quickly, but as the exchange continues, the concentration of the K and Na molecules released into the solution slows the exchange down and it will eventually come into equilibrium. The buffering process can be done in 10 to 15 minutes—the point at which the exchange slows down enough that the greater exchange is not worth the wait.

Some coco products have been buffered with a higher treatment of Ca and Mg concentration. This creates a lower K and Na percentage on the exchange and adds the benefit of Mg to the CEC. These more advanced buffering processes involve a much greater amount of time, but result in much lower K and Na levels on the exchange. This essentially creates a better coco product from day one, ensuring all of a nutrient mix goes straight to the plant versus amending the coco’s CEC.

What Does This All Mean for the Grower?

As a grower, your goal is to create and use a well-balanced nutrient solution. If you are using an un-buffered coco product, a well-balanced nutrient solution goes into the coco and starts to buffer the coco as well as feed the plants, instead of all of the nutrients going directly to plants. So, the CEC in the coco is exchanging some of the K and Na for Ca and Mg. This exchange is now unbalancing your nutrient solution, increasing the K and Na while decreasing the Ca and Mg. How much unbalancing, you ask? Earlier, I mentioned the coco could have as much as 1.56 g of K and 0.35 g of Na per 100 g of coco. Your nutrient mix is not highly concentrated with Ca and Mg, but it is enough to get some of the K and Na released from the CEC.

About 15 years ago, I was growing roses in coco and we did a weekly chemical analysis of our feed and drain water. The first time we used coco, we noticed the Ca in our drain water was less than 40 ppm (we would have normally expected the Ca to read 100 to 150 ppm in the drain water), and we were feeding Ca at a rate of about 200 ppm. For the next two weeks, we had the same result, so we doubled our Ca to 400 ppm. The analysis of our drain water went up to about 50 ppm of Ca. We watched that for about three weeks and then started feeding Ca at about 500 ppm and still saw very little change in the Ca ppm in our drain water. It took about four months for our drain water Ca analysis to read about 100 ppm. The loss of the Ca and Mg is one thing, but you also get an increase of K and Na. High levels of K will hinder the uptake of Mg by plants. Sodium can negatively impact plant health even at low levels and is toxic to some plants starting at 50 ppm.

The widespread use of calcium and magnesium supplements in the indoor gardening industry is an indication that many have experienced the CEC phenomenon in coco that I am talking about here. The deficiencies are observed and can be corrected to a certain extent with calcium and magnesium supplements, but there are also coco products out there buffered to a higher level, which don’t need the calcium and magnesium supplements.

Click to expand...

Coco Mix

Coco Mix

So I did a mix and have a 20 gal pot. My plant experienced nutrient lockout as I was mixing a salt based nute with a calcium based nute. After I flushed to correct this issue I noticed a lot of fluctuation of my pH.

Anyway, my question is this: Is there a possibility that the medium that I am using caused my plant to intake extra N. Furthermore, about the drowning the pot to equalize the Osmotic pressure, could you use this as a treatment for something like nutrient lockout rather than doing a flush.

kcanz22 said:

So I did a mix and have a 20 gal pot. My plant experienced nutrient lockout as I was mixing a salt based nute with a calcium based nute. After I flushed to correct this issue I noticed a lot of fluctuation of my pH.

Anyway, my question is this: Is there a possibility that the medium that I am using caused my plant to intake extra N. Furthermore, about the drowning the pot to equalize the Osmotic pressure, could you use this as a treatment for something like nutrient lockout rather than doing a flush.

Click to expand...

sorry man, cannot understand your question... Can you explain better?

Different ions bond to colloids with different strenght, thats why I suggets to NOT flush with straight water: you'll end up with an unbalanced substrate as some ions (aka micro/macro elements) gets washed away very easely while others not.
Dunno if that can help you anyway...

Also, can you explain what you mean by "equalizing the osmotic pressure"

Thanks

Tc

definately a great thread, lots covered, but funny, I switched to coco and then got flooded out of house so had to move, and didnt flush the coco before planting and for some reason I was treating it like pro mix AND ph meter had calibration issue which turned out to be a bit of moisture on a battery had rust shorting it so it caused meter to od every use...fixed meter issue, did research found I need something closer to 6.0....so I transplanted into flushed medium, and now I am 17 days into flower in 1 gallon bags, 8 plants on a 3x6 table, 600w hps and 400w halide, feed about 900 ppm 3 times a day, 3/4 liter first watering, then 500 ml for each of the other 2, get some 20-40 % runoff, never do anything other than ph the food to 5.9, using baking soda for ph up, and plants are freaking out with tons of growth, GH nutes and cal mag, no ppm or ecc meters but well here is a short vid https://www.youtube.com/watch?v=nMUsSAo7K94 dehumidifier runs 40% all night off in day, not one bug gnat or anything , took 45 clones into same flushed medium 20% perlite 80% coco, and no rooting hormone or gel, 100% rooted...so since I am not paying attention to anything but ph how is it I have wicked plant growth, and insane rooting with clones...4 strains but 4 of them are unstable genetics, however the pheno I wanted I seemingly got, 2 diff phenos of bubba, one fast tall and the other fast and half the height with triple the size of stems on short plant, I think this is one in a million, and a cali big bud and one early vixen from crop king..., so why are they doing so well with no attention other than ph? Not looking to fix anything but cant be luck...

Thanks for the very useful info about growing in Coco.

Hey The Cook thanks so much for such quality infos shared.
Now I can say I commence to understand the mechanics of CEC on coco, thanks very much for your time to put this together in a great way very didactic I appreciate

going to pratice very soon...smaller pots...multifeedin...flush with nutes.

Old Moses said:

Hey The Cook thanks so much for such quality infos shared.
Now I can say I commence to understand the mechanics of CEC on coco, thanks very much for your time to put this together in a great way very didactic I appreciate

going to pratice very soon...smaller pots...multifeedin...flush with nutes.

Click to expand...

You're welcome bro!

Happy growin

TC

If they ever changed the guard to incorporate active users as subforum moderators you'd have my vote.

Mikell said:

If they ever changed the guard to incorporate active users as subforum moderators you'd have my vote.

Click to expand...

Lol thanks man

A really great work!
Thanx!!
Ciao, viva la pizza

Great post. Very informative and useful. 100% coco coir for the win!