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

[rolandkat12583]

Tab water vs CalMag +

Tab water vs CalMag +

Hi,

Thank you all in advance for the replies.

I am using RO water with 0 ppm.

I would like to know what is the different between adding CalMag+ to my RO water to get to ~200 ppm vs adding tab water to get to ~200 ppm?

Thanks again and great info.

 

[Mikell]

Nutrient make up varies on tap and it would have a higher carbonate hardness.

 

[rolandkat12583]

Thank you for the reply.

Which method would be better to control the ph swing from using RO water.

RO with CalMag+ or RO with 20% tap water?

I am in 100% coco with RO water. Running H&G nutes.

Thank you.

 

[Mikell]

Wrong person to ask, I've never used RO. I even misused the term carbonate hardness and meant to say alkalinity.

Create a separate thread, you'll attract someone with specific experience. If not here then in the Nutrient and Fertilizer subforum. OnlyOrnamental pokes around there and is a wealth of information.

 

[knuckles]

Thank you for the reply.

Which method would be better to control the ph swing from using RO water.

RO with CalMag+ or RO with 20% tap water?

I am in 100% coco with RO water. Running H&G nutes.

Thank you.

I’ve been adding tap water at 15% to the r/o,works for me I use canna nutrients as H&G sucks now!

 

[Cork144]

I had about 100 questions before my first coco attempt and this threads just solved about 99 of them, nice one

 

[slipperyslut]

Growing is something strange as it can be as much complicated as you want. Beside that, some growing methods needs a better understanding of the involved chemical processes than others. Coco coir (in my opinion) is one of them.

"Coco Coir tend to adsorb Calcium and Magnesium", "pH of nutrient solution should always be adjusted to the correct value", "checking drainage ec and pH is also important" as well as "checking drainage pH and ec makes no sense as coco holds nutrients and modify pH", "Coco is an inhert media"or "Coco has high CEC" are only few exemples of how many confusing infos can be found on the internet.

If you haven't heard none of this rules before, you are likely to have never grown in coco or at least, you were lucky enough to not need search the web for hints and tips.

Some of those rules are true, others are not, but in most cases they're only simplicistic aproximations of reality.

So, are you ready?

Step 1, the basics: pH, salts and Ions (aka the good, the Bad, the Ugly)
"Daddy, why seawater tastes that baaad?"
"Ohhh it's easy my son, it's cuz there is salt in it!"
"Wow you know lot of things daddy, but what is salt?"
Bump! Panic "ehm, son, why dont you go play with your friends now? It's summer! Have fun!"

Encyclopedia, Salt: elettrically neutral chemical compound, made of 2 or more Ions with opposite electrical charge.

Lets take a look at the seasalt, almost everybody knows that its chemical formula is NaCl. In its solid form is a quiet stable compound, but what happens when we put it in water?
Correct, it dissolves, but what it means?
What actually happens is that salt divides in its Ions: Na+Cl-
If we want to be exact, there is no salt in the solution, its crystalline structure got dissolved, just positive and negative Ions. Keep those last word in mind and put them in a corner, we'll need them soon.
Everything clear till now?
Good, lets go ahed.

Water!
Water has many characteristics, almost everyone quite unique. But when the talk is about Ions, two becomes particullary important: water is an amphoteric and polar compound. Lets start from the last one.

While the term "polar" could suggest something related to cold places, it actually referres to magnetic/electric poles. Saing water is "polar" simply means that its molecule is electrically asimmetric. Everybody knows water chemical formula is H2O and if you don't, please, pick up a lighter and set your hair on fire for punishment.
So 2 Hydrogen atoms and 1 Oxygen, but maybe not everyone knows that its structure it's like that:

View Image

As you can see, water molecule has some sort of triangular shape, with the oxygen side been slightly (it all depends on the point of view) negative charged, and viceversa.
Could seem a little thing, but without this there would be no plants to grow.

Amphoteric is somehow a weird word. Anyway it basically means that water can act as an acid as well as a base. For definition, an Acid is something capable of releasing H+ ions, while a base is something that attract them. If put thogeter with someting more acidic, water will act as a base and viceversa

Pure water at room temperature is made of stable H2O molecules, but a really small amount "divide" to H+ and OH-

Beware that "divide" is not correct, is more of an addition:

2 H2O <--> H3O+ OH-

At the end of the day it's basically the same thing, we always have a H+ on a side, and a OH- on the other. From know on, please consider H+ and H3O+ as the same thing. In most reactions you'll see H3O+ cause it's the real form, while when talking we'll refer to H+ for easier reading.

Anyway, I sad "only a small amount". Guess how many? 1 every 10.000.000 or 1 × 10-7. Look at that "-7". Ever wondered "why pH7"? now you know.

As we have seen pH7 also mean that H+ and OH- are present in the same concentration.
If you use RO water, thats quite near what comes out from the blue hose

But if we put an acid in it, water will act as a base, bonding to an H+

H2O + HCl -> H3O+ Cl-

More H3O+ compared to OH- The pH is lowering. Ten times more H+ means 1 point less in pH.

Viceversa H2O+NH3-> OH- NH4+
More OH- compared to H+. The pH is rising.

So I've just said pure water has pH7 so same amount of H+ and OH-.
Oh, well, there's a last minute problem, like when you see there's only 10gr left and you're still in Veg: pure water is a great solvent, enough powerful to react with CO2 normally present in air to create Carbonic Acid.

H2O+CO2 -> H2CO3

Being H2CO3 an acid, water play its role as a base, actracting H+ from the newcomer and lowering pH till a 5.5 value.

Why till 5.5 and not more? I've said water act as base when toghether with someting MORE acidic. In that case, 5.5 is the equilibrium point. Maybe you are allready thinking that adding your pH+ would be a simple solution but think about it: if you raise the pH, water will be once again basic if compared to H2CO3, at that time will start to act as a base as before.

Seems frustating doesn't it? Well, actually it's a great thing: the fact is that water by its own has a very low inertia to pH adjustment. In other word, easily matches pH of surrounding substances.

Know you should start to understand why the amphoteric behavior is so important.

But what about polarity?

The answer is quite simple (or at least more simple than the amphteric thing): polarity enables water dissolve salts crystalline structure and idrate positive and negative Ions.

Look at the picture below:
Salts in a water solution are like you and your girl dancing in the middle of 1000's Bred Pit & Angelina Jolie straight in the middle of a 7th year crisys.

Few minutes later, the situation will likely be like that on the right

View Image

Now stop thinking angelina's green eyes for a while (yes I am a romanthic guy) and focus on female plants. Fertilizers are salts, but plants need them in their ionic form to be able to adsorb them.

Now you know what salts and Ions are, how water acts like, and what happens when those 3 are put togheter.

"Wait, but the title said pH, salts and Ions, not water, salts and ions!! What da f**k was that for??"

Well, pH is like balance between brads and angelinas. Too many Brad and only few Angelina will make them forget about the 7year crisys and try hard to reconquest the few remaining ledies. In three words: you are screwd.

If you kept reading till now, i'm quite sure you have seen this graphic before:

View Image

I'll not explain them one by one, but keep in mind that any significative change from pH7 could cause serius issues. As said before, 1 point more in pH means 10 times more OH- and 2 point more means 100 times more OH-, the opposite for H+ ions.

Roots use H+ and OH- to adsorb macro and micro elements, so pH balance in the nutrient solution is very important to make it possible. Beside that, different pH causes different equilibrium between ions, making possible reactions that doesn't happen under neutral conditions, resulting for example in unsolvable salts.
Undissolved salt means (quite) no ions, and no ions means no food for the plant.

"

Water!
Water has many characteristics, almost everyone quite unique. But when the talk is about Ions, two becomes particullary important: water is an amphoteric and polar compound. Lets start from the last one.

While the term "polar" could suggest something related to cold places, it actually referres to magnetic/electric poles. Saing water is "polar" simply means that its molecule is electrically asimmetric. Everybody knows water chemical formula is H2O and if you don't, please, pick up a lighter and set your hair on fire for punishment.
So 2 Hydrogen atoms and 1 Oxygen, but maybe not everyone knows that its structure it's like that:"

​

You are an awesome chemistry writer but like most smart people who love technical science you’re not a very good teacher at turning complicated info into something relevant and easy to understand for a girl like me who failed chemistry in “high” school.

I could never concentrate, cause I was always fucking my brains out...


I can never concentrate now, cause I’m still always fucking my brains out!


When I have zee time to read every part of your awesome post at least 10 more times, maybe I’ll understand what the hell you’re talking about. I’ll add my own post to make it all easy to understand for people like me. Until then, I’ll just trust that you know what you’re talking about, cause I’ve always wanted to try coco.


So why does a Dumb Blond with green eyes like me run one of zee biggest underground grow ops in BC? I grew up with my Granny who was a master gardener who grew zee biggest, sweetest juiciest veggies around. She grew them all in her dirt garden so I learned how to grow in dirt, and its not rocket science like you turn growing with coco into. Back in the BC mountains where nobody goes where our Grow Op is, there’s lots of rich beautiful VIRGIN soil, so why would I import a foreign substance at high cost from a completely different part of zee world? I’m a rich girl with lots of money to play with and I like to experiment, that’s why! Part of our operation in zee winter is in an abandon gold mine. We get all of our power from our wind turbines, Solar panels and a big honk’n emergency bio-diesel generator. We use dirt to grow in there too, but I’ve always wanted to play with coco in a hydroponic set up to compare it to growing in dirt. I C lots of awesome You Tube videos about coco and want to try it.

First I will study all your awesome posts until I understand zee science, but in zee meantime I would like to ask your big scientific brain for some help in answering a question of mine. First I need to tell you a story that’s true, so you’ll know where I’m coming from:

With over 5000 plants split between growing in greenhouses in Spring to Fall and our mine shaft in zee winter, and multiple harvests every year, we need good auto-trimming machines to get zee trimming done fast and still have perfect hand-trimmed looking Buds to sell to our dispensary and extraction companies. We don’t like hand-trimmers because they’re too slow and not to be trusted. Keeping our Op secret is why we’ve been in business for so long and got so big without getting caught. We’ve tried them all and now we only use one brand of trimmer for one reason. All trimmers with blades stole a lot of our resin + valuable trichomes which get stuck to zee blades. That is why we prefer zee “Tom’s Tumble Trimmer” because they don’t use blades but a mesh drum and they never run down, trim perfectly and never need cleaning. This is because they have a secret patented medical/food grade solid mesh material where NONE of our sticky resins and valuable trichomes stick to it in zee trimming process.
So this my question for your big sexy scientific brain to help me answer:

If zee mesh is made of a secret, patented medical/food grade solid material where none of zee chemicals used to make it (we always have our Buds lab-tested for organic purity) ever rub off on our Buds, (because it works like Teflon), why do all of our Buds keep 99% of our resins and trichomes and nothing ever sticks to zee mesh?
We take pride in our Buds for their medical-grade all-organic non-chemical purity, so how can this mesh which is made of nothing BUT chemicals keep our Buds so pure?


If you could answer my question Mr. Cook I’d really appreciate it because some of our big buyers who know what we trim with want to know and I’d like to give them a big sexy scientific answer without giving their secret patent away!

 

[xxPeacePipexx]

And some people say coir is the training wheels for hydroponics..

 

[mean mr.mustard]

Coir is hydroponics.

 

[Kesey]

Shouldn't you be concerned about carbonate build up from .4 EC starting water in frequent irrigation, small container systems?

 

[The.Cook]

Shouldn't you be concerned about carbonate build up from .4 EC starting water in frequent irrigation, small container systems?

I'd say not really unless you're planning for a very long run.