Buffer Coco coir

Can I use calcium nitrate and Epsom salts to buffer Coco coir or do I specifically have to use cal-mag?

Less than ideal.

One of my favorite cocoholic sites.
They explain things pretty well. Just one source of info, fwiw.


"How to select a CalMag supplement

I use and recommend General Hydroponics CaliMagic. It is formulated to deliver a high dose of Ca and Mg without significantly contributing to the amount of nitrogen, phosphorous or potassium. When selecting a CalMag product, be aware of the quantity of nitrogen (N) in particular. N is the first number in the three number set listed on all fertilizers, for Calimagic it is 1-0-0. Many CalMag products also deliver high doses of N, which can create problems with your nutrient element ratio."




This helps explain why cal/mag is continually needed thru the grow.......the coco is sucking it up as it breaks down.

"Why do you need Cal Mag Supplement If the Coco is Buffered?

The simple answer is that the coco is constantly breaking down. As large fibers of coco break down in the pots they expose new surface areas of the coco fiber. This also exposes new cation exchange sites that will take Ca and Mg from your nutrient solution and reduce the amount available to the plant."

Thanks for the info

Treedoctor123 said:

Can I use calcium nitrate and Epsom salts to buffer Coco coir or do I specifically have to use cal-mag?

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Yes you can use calcium nitrate and magnesium sulfate.

But most decent coco is already pre-buffered. I just rehydrate with 1/4 strength nutrient solution. But I use a three part dry product and one part is calcium nitrate. The micronutrient part is 2% magnesium. If you use calcium nitrate for your nitrogen source and use it throughout the grow you don't need calmag. I never use it and I grow in 100% coco and never have any calcium or magnesium deficiencies. I have been growing in coco for years and before that it was flood and drain hydro in hydroton. I've never bought or used calmag in my life. If the base nutes contain enough already you don't need to supplement with an additive. But most nutrient lines are purposely lacking in calcium so they can sell you a bottle of their calmag. Most cannabis specific nutes are formulated this way. That's why I don't use cannabis specific products. They're formulated to require you to buy more products to provide what has been left out of the base.

So what do you use then? I presuming nutes for tomatoes and such.

WinterSoldier89 said:

So what do you use then? I presuming nutes for tomatoes and such.

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I use basically the same stuff that the expensive cannabis specific nutes are made with. I just don't pay for a cool sounding name and a fancy label on a bottle. I buy the ingredients in dry form and mix them with water myself.

This is what I use. It's not tomato food it's plant food. Cannabis is a plant. It doesn't need anything special. The same elements other plants use to grow are the same elements cannabis uses. Overpriced cannabis specific nutes are a waste of money.

Calcium nitrate, micronutrients, MKP, potassium sulphate, and magnesium sulfate "epsom salts".

Hello, just a quick question. So this is my first time growing in Coco coir, that being said I've done the research and it's advised to rinse the coir good! Then buffer it by adding Calmag. Okay, I understand all of that. My question is after I've done that and everything is good to go my plant is in its new medium. When or do I start adding Calmag into feed schedule? I've tried asking around Google but nothing is giving me the answer I'm seeking. Hopefully all of that made sense

Jdmboi1 said:

Hello, just a quick question. So this is my first time growing in Coco coir, that being said I've done the research and it's advised to rinse the coir good! Then buffer it by adding Calmag. Okay, I understand all of that. My question is after I've done that and everything is good to go my plant is in its new medium. When or do I start adding Calmag into feed schedule? I've tried asking around Google but nothing is giving me the answer I'm seeking. Hopefully all of that made sense

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Are you using tap water or RO? If tap, what is the EC (or PPM)? If using RO, you should definitely add calmag every time.
If using a standard calcium nitrate-based calmag such as Botanicare, use 5ml/gal. That should add about 0.42 EC (210 PPM).
If using calcium cabronate based GH Cali Magic, also use 5ml/gal. It will raise your EC a lot more though. 5ml/gal used to give me an EC of 0.58 (290 PPM). I swear they made it stronger a few years back, and now it's well over 0.6 EC.
Anyway, your overall EC/PPM numbers will be higher when using the CaliMagic. Don't worry about it. If you use less you'll get a calmag deficiency.
Personally, no matter how well I follow the instructions and run solution through the coco, my plants always get yellow for a while after transplanting into it. I've given up on coco, gone back to peat-based Sunshine Advanced #4 Aggregate mix.

I've been growing in coco for years and very rarely do I have to use a calmag supplement.
I use buffered coco right out of the bag without any type of prep.

MickFoster said:

I've been growing in coco for years and very rarely do I have to use a calmag supplement.
I use buffered coco right out of the bag without any type of prep.

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I've never used calmag. I use calcium nitrate for my nitrogen source. It supplies all the calcium needed if growing in coco.

Most coco is already buffered and ready to go. Years ago it wasn't and there was some pretty crappy coco that you needed to rinse all the salt out of. That's all being done today by every decent coco supplier. I think people are following old advice because they're rinsing coco that is already rinsed, buffered and ready to grow in.

xtsho said:

I've never used calmag. I use calcium nitrate for my nitrogen source. It supplies all the calcium needed if growing in coco.

Most coco is already buffered and ready to go. Years ago it wasn't and there was some pretty crappy coco that you needed to rinse all the salt out of. That's all being done today by every decent coco supplier. I think people are following old advice because they're rinsing coco that is already rinsed, buffered and ready to grow in.

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I've used Canna coco and Tupur mix in the past, most recently Char Coir. It's supposed to be one of the best. Whether I use it straight out of the bag, or run solution through it first, the plants get less green. It's okay though, I'm fine with not using coco. I'm glad it's working for everyone else with the water available at their location.

If you buffer, or double buffer your coco coir then you add calmag/calcium/whatever as you normally would every feeding.

I wouldn't say a double buffer would be any good to already buffered coco but like cannacoco bricks they are lightly buffered so I buffer at 100% solution instead of the recommended 150%

Coco is overrated. Get some hydroton for hydro or go full organic soil, everything else is a waste of time.

OG Doge said:

Coco is overrated. Get some hydroton for hydro or go full organic soil, everything else is a waste of time.

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Hydroton is overrated. Get some coco for hydro or go full organic soil, everything else is a waste of time.

Opinions! They're whats for dinner.

Amaximus said:

Opinions! They're whats for dinner.

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True, but baseless opinions vs opinions based on experience have different values. I've ran coco for years, it works, yields are good, but it is a pain in the ass dealing with the K, C, N fluctuations due to the wet dry cycle, as well as all the fungus gnats that come in every bag. Some people like to make things harder on themselves and coco is for them. I like a simple reusable inert medium such as hydroton, my grows are easier now with the quality and yield being better.

OG Doge said:

True, but baseless opinions vs opinions based on experience have different values. I've ran coco for years, it works, yields are good, but it is a pain in the ass dealing with the K, C, N fluctuations due to the wet dry cycle, as well as all the fungus gnats that come in every bag. Some people like to make things harder on themselves and coco is for them. I like a simple reusable inert medium such as hydroton, my grows are easier now with the quality and yield being better.

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Sounds like grower error

Gemtree said:

Sounds like grower error

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Not at all, I grew with coco successfully for years, just don't need the extra problems it brings along. I'm yielding 0.5 lbs more per 4x4 with hydroton, I also learned better ways of growing so maybe hydroton doesnt explain improvement, but it is easier and reusable, just my experience.