# Calcium Supplementation



## Carper (Nov 5, 2010)

Hi Everyone,

I feed my multigrowth paphs and phrags with the MSU fert 13-3-15 and have had very good success. I have managed to work out over the last year or so what strength I can feed at which is about 80 ppm Nitrogen without any negative effects. This matches my conditions in the UK which are not as favourable as yours I'm afraid, ie less sun etc. I have been supplementing magnesium in the form of epsom salts which basically increases it by approx 50% from whats in the MSU. The plants certainly look healthier and greener. I am now considering an increase in calcium also by approx 50% to the MSU in the form of calcium nitrate. Any thoughts or recommendations, negatives or positives would be very helpful.

Thanks

Gary
UK


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## Ray (Nov 5, 2010)

I use CaNO3 as a medium presoak, but sell a great deal of it to growers who use it as a fertilizer supplement.

I have heard some concerns about it boosting the nitrogen too much, but as it is a 15.5-0-0-19Ca product, in order to increase the calcium by 50% over that of the MSU formula (2% to 3%), you'd only be adding about 3/4% additional N, so I doubt it would be an issue.


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## NYEric (Nov 5, 2010)

Increase your lighting.


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## Brabantia (Dec 1, 2010)

NYEric said:


> Increase your lighting.


Did you know the energy cost in Europa?


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## Brabantia (Dec 1, 2010)

Why do you want increase the calcium and magnesium content in your fertilyser solution? At 85 ppm N you have around 650 mgr/L of fertilyser in your solution. Having 8% Ca and 13% Mg in the powder fertilyser you have 52 mgr/L Ca and 13 mgr/L Mg. From the Wellenstein's paper (AnTec Laboratory) you are in the range they recommend for slipper orchids. I agree at the lower limit for Mg.


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## Rick (Dec 1, 2010)

Since you are presently seeing some positive effects, I'd hold off on any more increases and run what you are doing for a season and see what happens. You may want to back off on stuff rather than add more.

Unless you are starting with an RO water, your tap water already has more Ca than Mg in it, so I wouldn't spike any more Ca (which will fight with the boosted Mg anyway).


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## Brabantia (Dec 1, 2010)

Brabantia said:


> Why do you want increase the calcium and magnesium content in your fertilyser solution? At 85 ppm N you have around 650 mgr/L of fertilyser in your solution. Having 8% Ca and 13% Mg in the powder fertilyser you have 52 mgr/L Ca and 13 mgr/L Mg. From the Wellenstein's paper (AnTec Laboratory) you are in the range they recommend for slipper orchids. I agree at the lower limit for Mg.



*Correction*
Sorry, 2.6% of magnesium (Mg) in MSU not 13%. Your content in Mg is thus: 16.9 mgr/L. My previous conclusion remains valid.


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## Masdyman (Dec 5, 2010)

I am not sure about this, i don't know where a stand as in one hand i think, why supplement when you already have a good feeding regime so why bother with the extra cost/hassle. In the other hand i think maybe it would be beneficial to the plants. At the moment my plants are growing well so i won't be supplementing, i do add Calcium /Mg as a pre soak to CHC.


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## Rick (Dec 5, 2010)

An old horticulture standard for supplementation is bonemeal.

Lots of Ca and Phosphate (instead of nitrogen) in a time release top dress.:wink:


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## Eric Muehlbauer (Dec 5, 2010)

I had read somewhere that modern bonemeal is too highly processed...and that the old fashioned bone meal had far more nutrients.


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## Rick (Dec 5, 2010)

Eric Muehlbauer said:


> I had read somewhere that modern bonemeal is too highly processed...and that the old fashioned bone meal had far more nutrients.



There was some worry about mad cow disease, so they cooked the snot out of it. I've been using pig bonemeal instead, which hasn't been processed quite as much.


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## Eric Muehlbauer (Dec 5, 2010)

I had read about the overprocessing even before mad cow...but I do remember bone meal being a concern when mad cow was at its worst. Do they make fish bonemeal?


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## Brian Monk (Dec 5, 2010)

Cooking bone meal won't significantly alter its mineral content. Other organic compounds, maybe, but as I understand, bonemeal is provided mostly for phosphorous. Potash used to be made simply by burning bones.


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## likespaphs (Dec 5, 2010)

any suggestions for quantity of oyster shell to put in 2 inch or 4 inch pots?


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## goldenrose (Dec 6, 2010)

I don't know that there's a specific dose, I just sprinkle a spoonful over the top.


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## Rick (Dec 6, 2010)

goldenrose said:


> I don't know that there's a specific dose, I just sprinkle a spoonful over the top.




That's probably as good as any other measure, and I've done that too.

Oyster shell ends up working very much like bone meal after its sucked up excess P for a while, and then when the biomass and orchids latch into it it's like a slow P release.


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## Carper (Dec 9, 2010)

I do start with RO water which has a reading of about 40 m/s, therefore you know what feed your putting in is what the plant is getting. After 12 months of using the MSU 13-3-15 regularly, virtually all my plants look and feel healthier, from leaves to roots. I am looking forward to see how they will flower when the spring returns and there are good signs at present. There seems to be a good number of paphs that look as though they are preparing to throw up spikes. Some are already in the process. As my water feed has now frozen to the ghouse, I am having to use tap water anyway, which is reading at 700 m/s so I am making up only a very weak feed solution. The calcium will be already at a higher level, so obviously am not adding anything extra at the moment. 

Gary
UK


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## likespaphs (Dec 15, 2010)

any thoughts as to whether to use fine (like flour) or chunkier oyster shell?


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## Erythrone (Dec 15, 2010)

Because of its fine particle size and therefore its greater surface area, the calcium supplied by "oyster shell flour" should be readily available... It happens if we use fine lime instead of "granular" lime in the garden. It must be the same for other "flours".

But.... I would avoid "flour" since the finer stuff will go away with water. Orchid meadia with bark, leca, etc. do not retain very fine stuff well!


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## Ray (Dec 15, 2010)

OK. Science nerd warning:

Just how "readily available" is Ca from oyster shell? It's not the most soluble material known to mankind.


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## gonewild (Dec 15, 2010)

Ray said:


> OK. Science nerd warning:
> 
> Just how "readily available" is Ca from oyster shell? It's not the most soluble material known to mankind.



Once you put it in the pot it is 100% readily available! At that point it is up to the plant to use it or not. oke:

You are right Ray the calcium won't instantly dissolve even from the flour size particles and the flour particles will actually was through the media and out the drainage holes.

I am thinking that many plants like paphs and phrags get a great deal of benefit from having their roots actually in contact with calcium containing materials like limestone or oyster shell. I know P.kovachii does. I think the roots actually take calcium directly from the media more efficiently than absorbing dissolved calcium in the water. For that reason now I mix the oyster shell into the media. When the oyster shell has all dissolved away it is time to repot.


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## Erythrone (Dec 15, 2010)

I didn't mean that oyster shell was very soluble, Ray! Excuse me, I speak French. Traduction of my ideas is not always easy.

I agree that oyster shell does not instantly dissolve (nor « traditional » lime that is applied on top of fields in agriculture or on maple forest "floor" here when the soil is too acidic or when there is Calcium deficiency in the ecosystem). 

Oyster shell is mainly composed of calcium carbonate, no ? Calcium carbonate is not very soluble in water, but there are more Ca++ in solution when the solution is more acidic, isn't it ? If I remember what I learned at school, roots plants acidify soil (H+). I suppose that calcium carbonate in the mix can dissolve a little more at the root « level »... Of course, calcium leaching is a reality too...

But if calcium carbonate dissolve slowly, I supposed that adding oyster shells to our mixex can have a rather long effect.


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## Rick (Dec 15, 2010)

gonewild said:


> Once you put it in the pot it is 100% readily available! At that point it is up to the plant to use it or not. oke:
> 
> You are right Ray the calcium won't instantly dissolve even from the flour size particles and the flour particles will actually was through the media and out the drainage holes.
> 
> I am thinking that many plants like paphs and phrags get a great deal of benefit from having their roots actually in contact with calcium containing materials like limestone or oyster shell. I know P.kovachii does. I think the roots actually take calcium directly from the media more efficiently than absorbing dissolved calcium in the water. For that reason now I mix the oyster shell into the media. When the oyster shell has all dissolved away it is time to repot.



A ways back when this question first came up on this site, I took a spoonful of rinsed oyster shell, stuck it in a bottle of distilled water, shook it every now and then for a day or so, and then took it in the lab. I found that it raised the pH almost to 9.0 and got quite a noticeable amount of hardness out of it (i.e dissolved Ca and Mg). In a potting mix with bacteria, fungus, roots and various micro niches (the rhizosphere) that are primarily acidic, I bet the rate of oyster shell decomposition can be much faster. I think one of the bigger benefits of adding oyster shell, limestone, or bone meal is for pH control and keeping the mix "sweeter" over longer periods of time than you would achieve without it. Most of the nutrients that plants want are most available in that 5.5 to 6.5 s.u. range.


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## Rick (Dec 15, 2010)

I just tried looking at this from a "plants are plants' aspect for an alternate view.

I looked up the mineral composition of seawater:

Sodium = 10,800ppm
Potassium = 392ppm
Calcium = 411ppm 
Magnesium = 1290ppm (3X the amount of Ca on a weight basis, 5X the molar equivalents.)

Then I looked at the mineral composition of Kelp (a marine plant):
Sodium = 3,700mg
Potassium = 13,000mg
Calcium = 1,000mg (25 molar eq)
Magnesium = 610mg (25 molar eq) (i.e. 1:1 Ca to Mg ratio)

From the Antec site looking at the relative number of atoms of each metal for orchids:
Sodium = not listed
Potassium = 250,000
Calcium = 125,000
Magnesium = 80,000 (i.e. 1.56:1 Ca to Mg ratio)

At least for K, Ca, and Mg, there is quite a bit of similarity between Kelp growing in hydroponically overloaded magnesium rich mixture and orchids typically grown with more calcium available than magnesium. However one should note the growth rate of kelp is way higher than for orchids.

In chemical and many biological systems, Ca can be antagonistic to Mg, so at this time I'd avoid lopsiding the amount of Ca in the environment around my orchids much beyond a 2:1 by weight ratio. Most surface, well, and tap waters already have much more Ca than Mg. So I'm finding that the more I use oyster shell or bonemeal, the more Epsom salts I need to balance it out.


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## Rick (Dec 15, 2010)

Maybe we should consider dolomite rather than oyster shell.

It's about 50/50 CaO/MgO


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## gonewild (Dec 16, 2010)

Rick said:


> Maybe we should consider dolomite rather than oyster shell.
> 
> It's about 50/50 CaO/MgO



I would much prefer dolomite over oyster shell. 

I have tried to find crushed dolomite but can't find a source, at least not on the west coast. Plenty of powder and even pelletized but not crushed rock dolomite or even limestone. Powder or little pellets degrades too fast in the media.

I did once do a side by side test with oyster shell and crushed limestone. (had to crush it myself, never again!)
I mixed different ratios of both shell and limestone into the media from 10% up to 100% and grew Phrag seedlings for 1 year. I concluded that there was no visible difference in growth results between the shell or limestone. The percentage in the mix did not make a difference except ....

The addition of shell or limestone increased growth at all percentages except
100% oyster shell reduced growth whereas 100% limestone did not. But I think this was a result of the flat shape of the shells as compared to the chunky limestone causing a poor media environment.

Two points to consider about the above are that most of the seedlings were P.kovachii which likely need a higher pH and all the pots got daily irrigation with an MSU fertilizer solution with added Mg so there was flushing of the free water in the media.


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## Rick (Dec 16, 2010)

I found that there is a dolomite quarry in TN (but not near me or very accesable). Several local Coops have different grades of pelletized lime or dolomitic lime with varying amounts of Mg, but only Morton's Supply in McMinville, TN said they had "dolomite". $5 pe 50lb. probably cost $50 in slow boat shipping to the west coast.

Also check out some aquarium stores. I saw a company that was packaging crushed dolomite for African Cichlids, and we used to get it for salt water aquarium gravel when I was in Calif.

Did you use RO water for your experiment? SOCal tap water probably has lots of ca and mg in it to start with.


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## Paphman910 (Dec 16, 2010)

What about crushed Coral that they sell in fish aquarium shops?

Paphman910


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## gonewild (Dec 16, 2010)

Rick said:


> I found that there is a dolomite quarry in TN (but not near me or very accesable). Several local Coops have different grades of pelletized lime or dolomitic lime with varying amounts of Mg, but only Morton's Supply in McMinville, TN said they had "dolomite". $5 pe 50lb. probably cost $50 in slow boat shipping to the west coast.
> 
> Also check out some aquarium stores. I saw a company that was packaging crushed dolomite for African Cichlids, and we used to get it for salt water aquarium gravel when I was in Calif.
> 
> Did you use RO water for your experiment? SOCal tap water probably has lots of ca and mg in it to start with.



Yes, RO water. Most tap water in CA is toxic. RO water to mix the MSU and RO water when ever I want plain water. Even RO water through the auto mist system.

Is the 50# bag from Morton crushed like gravel or pulverized like sand? The aquarium stores around here only have crushed coral for gravel. They say it is from fossil sources but I don't know what the sodium content might be. 
So I just use the oyster shell from the feed store across the street and it works. But still if I had the option I would use dolomite gravel.


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## gonewild (Dec 16, 2010)

Paphman910 said:


> What about crushed Coral that they sell in fish aquarium shops?
> 
> Paphman910



Just mentioned that in my last post after you posted this. 
I am not sure about possible sodium content of the coral. If the coral is actually from fossil deposits the sodium may all be leached out but maybe not?


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## Eric Muehlbauer (Dec 16, 2010)

There was a thread about this a year or 2 ago. Apparently the crushed coral is very good, no salts. I tried a bag of it...there were no problems. Right now, I'm using Espoma pelletized dolomite. Again, no problems. I also used to put marble chunks on the bottom of my parvi and brachy pots, so that the roots would be touching the rock. Not sure it did anything better than would have been without the rock.


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## Erythrone (Dec 16, 2010)

Interesting.... I never thought about crushed coral!!! Here it is easy to buy many kind of lime.

For Marble: it is a metamorphic rock, derived from sedimentary calcarous rock. But it does not react like lime. They simply don't have the same properties.

I remember that marble doesn't react with acid (no bubbles!!! If we add acid on calcarous sedimentary rock, there is a strong reaction. But no reaction with marble. This is a method for identifying rocks) Can marble be useful in our mixes?


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## Eric Muehlbauer (Dec 16, 2010)

Metamorphism shouldn't change the chemical characteristics of a rock. In the earth science classes I've taught, I always used HCL as a test for marble as well as limestone, and it reacted. However, I believe that marble can be derived from dolomite also, and I haven't found dolomite to react as well to HCL. It may not react at all. That said, I have heard, maybe because of its density, that marble isn't as good as limestone. However, whenever I see people using marble mulch over azaleas and rhododendrons (an unfortunately common sight in my neighborhood) the shrubs are always chlorotic, so it must have some effect on soil pH.


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## Rick (Dec 16, 2010)

Erythrone said:


> Interesting.... I never thought about crushed coral!!! Here it is easy to buy many kind of lime.
> 
> For Marble: it is a metamorphic rock, derived from sedimentary calcarous rock. But it does not react like lime. They simply don't have the same properties.
> 
> I remember that marble doesn't react with acid (no bubbles!!! If we add acid on calcarous sedimentary rock, there is a strong reaction. But no reaction with marble. This is a method for identifying rocks) Can marble be useful in our mixes?



Marble has virtually no buffering capacity. As you noticed it doesn't react to acid and it's very hard. That's why it makes great counter tops.

I don't know what the magnesium composition is of crushed coral. And the magnesium composition of dolomitic limestone can be from 5-20%. Pure dolomite is 50/50 CaO/MgO. So getting lime or dolomitic lime from the COOPS maybe a real crap shoot as to how much magnesium is in the bag.

I couldn't get a straight answer from Morton's as to whether they were selling straight dolomite or dolomitic limestone, but it is "pelletized" so I'm assuming the grain size to be at least a couple millimeters.


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## Ray (Dec 17, 2010)

Pelletized lime and dolomite are often just powder that is bound by water-soluble polymeric materials. It is intended to provide for easy broadcast on lawns, then in rapidly breaks down into powder so it can go to work.

I'd be wary of using it, for fear of a sudden release.


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## Erythrone (Dec 17, 2010)

Rick said:


> Marble has virtually no buffering capacity. As you noticed it doesn't react to acid and it's very hard. That's why it makes great counter tops.



So I am not crazy?


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## gonewild (Dec 17, 2010)

This is not the best place to ask if you are crazy. :rollhappy:

Good to know that the crushed coral does not have sodium content.

I think marble would be something like using a ceramic. It is composed of minerals but a heat process has altered the availability of the minerals to plants and the environment. 

Marble does not dissolve or easily break down in a moist environment so it would not provide what we are looking for in limestone.

Dolomite pellets break down too fast so they don't offer a long term source of minerals in the root zone. 

The small size of dolomite pellets does not give much surface area for a root to be in contact with.


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## Rick (Dec 19, 2010)

Ray said:


> Pelletized lime and dolomite are often just powder that is bound by water-soluble polymeric materials. It is intended to provide for easy broadcast on lawns, then in rapidly breaks down into powder so it can go to work.
> 
> I'd be wary of using it, for fear of a sudden release.



I just picked up a $4 bag of the EPSOMA Garden Lime

It's made from dolomitic limestone and has a 
guaranteed analysis of 21% Ca and 10% Mg

As carbonate minerals it looks pretty close to straight dolomite of 52% calcium carbonate, and 35% Mag carbonate (still a bit shy on Mag).

It is pelletized, and from my test on the kitchen counter it looks like it will break down into a fine sand/silt after a short time in water (as Ray said).

But it looks like it will go a long ways with an application of around 5 lbs per 100 sqft to maintain a pH of about 6.5

On the directions is says 2-4 tbspoons per plant, but I don't know if this comes out at the same dose as the above.

I just did some converting and came up with about 2.5gr per 4" pot.


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## Rick (Dec 22, 2010)

2.5 gr came out to 1/4 to 1/2 tspn.

I also put 2.5 gr into 50ml water and measured pH (came out to 10.3).

So if you use it then I would only use it for acidic mixes and sparingly.

I'm also still trying to get some real dolomite, but so far I've only come across some expensive ($16/L without shipping) from a specialty aquarium supply.


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## Ray (Dec 23, 2010)

Rick, check local Petco and Petsmart stores. I have purchased dolomite aquarium substrate from them. It's great for African cichlids.

I purchased a bag of dolomitic limestone yesterday - again in the roughly 3:2 Ca:Mg ratio, but why is that bad? My understanding is that while plants need both, they don't need them equally, making me think that 3:2 is still probably overkill on the Mg.


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## Rick (Dec 23, 2010)

Ray said:


> Rick, check local Petco and Petsmart stores. I have purchased dolomite aquarium substrate from them. It's great for African cichlids.
> 
> I purchased a bag of dolomitic limestone yesterday - again in the roughly 3:2 Ca:Mg ratio, but why is that bad? My understanding is that while plants need both, they don't need them equally, making me think that 3:2 is still probably overkill on the Mg.



Thanks Ray, There is a Petsmart nearby I'll try.

Most of what I've seen in the literature is that on a weight basis, plants are using 2-3X the calcium than magnesium, but since the molecular weight of Ca is about 2X that of Mg, they are using Mg at just about the same rate (per molecule) basis. 

So I wouldn't mind using some dolomitic limestone with the 3:2 ratio that you've gotten hold of, but I think the higher ratio (Ca) materials are at a minimum a Ca waste or potentially somewhat inhibitive. Especially in combination of common surface/tap waters that may already have a 5:1 Ca/Mg ratio.


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## Rick (Dec 24, 2010)

I was looking up an article from Averyanov on the "dependency" of P emersonia and P hangianum on different types of limestone.

P.emersonia growing on hard crystaline limestone (probably high aragonite, Ca), and P. hangianum growing on soft crumbly stratified limestone (probably yellow dolomite, high Mg).

This article was referenced in an article of Helger Perner who grows P. hangianum successfully in a mix of sphagnum and tree fern (no lime amendments). Which makes another case for my use of baskets of sphag as a good option for growing paphs I guess.

No telling how much Ca or Mg is in Pelger's fertilizer or irrigation water, since I didn't recall seeing any mention of it in the article, but once again it points to the final notion that we probably overdo are emphasis on mineral nutrition (or some are real lucky with their local water supply).


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## Ray (Dec 24, 2010)

The stuff I got is intended for acidic-water neutralization, and is a crushed material that looks like coarse sand. I originally bought it to "mineralize" the RO water feeding my refrigerator - the coffee made with it tastes SO much better than it did with straight RO.

I'll be offering it in 2# bags soon.


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## Rick (Dec 25, 2010)

Looked up this cool article on mineral content of sphagnum

http://www.springerlink.com/content/ktq651w0788v4k74/fulltext.pdf

Two things that pop out is:


The ratio of Ca to Mg is variable based on source ranging from 5:1 to 1.5:1, and

The amount of Ca and Mg (in fact probably most metals) is high enough to not need any external additions from fertilizers provided you get some decomposition of the cell walls.


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