Oyster shell substitute for dolomite

Hey RIU,

Genghis here just found a place that sells oyster shells, mushrooms compost the works for cheap and by the lbs, so i bought 5 lbs of oyster shells for a dollar and pulverized and powdered them down myself using a mortar and thistle.

My question is would this be sufficient for my calcium carbonate to buffer ph, as well as just a nice soluble calcium source once broken down into my mix.

Thought about using a 1/2 cup to 1 c.f.

Any input and or ways to pulverize and break down the oyster shells would be appreciated

Happy growing
GK

Sledge, Mallet, hammer, chicken tenderizer, something along those lines and a heavy duty tarp to wrap around the shells. Maybe add dirt to reduce the impact on the tarp. Beat over concrete or a hardwood.

and its a mortar and pestle.

LOL, yeah, that mortar and thistle might take a bit of thyme.

Unless you get the oyster shells to the consistency of flour, like the dolomite, you are pretty much pissing in the wind, or will be waiting 3+ years for it to break down.

At less than $5 for a 40lb bag of Dolomite, it's really not worth all the effort and besides sounding cooler, the differences are negligible in real use.

Wet

LOL they make a mortar and thistle now eh?? sounds painful...

Wetdog said:

besides sounding cooler, the differences are negligible in real use.

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I'd debate that...dolomite has it's place for long term agricultural applications, but it is not the same as oyster shell powder. the differences are important...

here is a run down of a few common soil additives (from cootz):

Calcitic Lime - pure Calcium Carbonate (CaCO3)

Oyster Shell Powder - pure Calcium Carbonate

Limestone - Calcite Lime contains Calcium Carbonate and Magnesium Carbonate (MgCO3) at 5% or less

Dolomite Lime - Some Limestone deposits contain both Calcium and Magnesium Carbonates. The mineral Dolomite (CaCO3•MgCO3) contains equimolar amounts of Calcium Carbonate & Magnesium Carbonate. The chemical composition of Dolomite by weight is 54% Calcium Carbonate and 46% Magnesium Carbonate. Limestones with intermediate content of Magnesium Carbonate (5% - 35%) are clasified as Magnesium Limestones.

as you can see..calcitic lime and oyster shell are identical (pure CaCO3)...but dolomite has a huge amount of magnesium in it. some of this magnesium is good to have around...but nowhere near the amount that dolomite contains. too much magnesium = gnarly soil compaction issues, not to mention plant growth issues...

dolomite doesn't fit in very well w/ albrecht ratios...

IMO oyster shell flour is a much more appropriate choice..and can be just as cost effective ($9 for a 50lb bag at some feed stores...)

here is the soil mix I used last time and it is working like a charm...check out my journal and you can see how happy my ladies are hehe...no dolomite


25% EWC/compost
25% pumice/rice hulls
50% sphagnum (make sure to hydrate first!!!)

per cuft of base mix:

5 cups rock dust mix (4x glacial, 1x basalt, 1x bentonite, 1x oyster shell)
1/2 cup gypsum
1/2 cup neem/karanja meal
1/2 cup crab shell meal
1/2 cup kelp meal
1 cup biochar

so yeah...1/2 cup per cuft sounds about right...maybe even a bit more. i'd throw some gypsum in there for the sulfur but thats just me...


i'd look for a source of pre-ground oyster shell (called flour, or powder) because the mortar and pestle thing gets annoying after a while..trust me.....i tried to do what you are doing and then eventually gave in and bought the flour...its worth the $$ to save all the hours grinding away..

wet makes a great point about particle size and availability...it needs to be a fine powder to become available immediately. if you are planning on using this soil mix for a while then you can throw in some of the chunky shells for aeration/long term calcium. just a thought..

Mortar And Pestle* excuse me lol and I have garden lime I'm just a little skeptical to use it as I am running into problems in my current grow although that could be stemming from a number of hypotheses I have.

But yeah it was a bitch and took about 2 hours to get that half cup pulverized and powdered.

Still added to my soil anyways as it was i'd say about 2/3 powder 1/3 small chunks.

Quick question though when i added it into the mix i had not mixed the soil yet and it already had mycelium formations, so i inevitably mixed the soil as that was going to be my last ingredient and the only gypsum I could find I didn't really want to mess with but any other recommendations are appreciated I just kind of don't like the store bought products if I can make it myself or I guess buy online I'm down ya know.

So as it stands my soil mix is as follows:

2.5 gallons Wiggle worm EWC
2.5 gallons SPM
2.5 gallons Vermiculite/Perlite

1.5 cups of kelp meal
1.5 cup of Epsoma plant tone
1/2 cup of Powdered Oyster shells
4 cups of Azomite as it was the only GRD I could find at the time

Working on getting a worm farm but this time of year red wigglers are hard to find and being reproduced for the upcoming season and I am a little skeptical using Nightcrawlers but I might give it a whirl, because while being slow to reproduce they apparently eat their fill in food.

Also if you see anything I'm missing let me know because I'm open to criticisms and opinionated and unbiased thought,

--I also have 200x powdered aloe(cloning dip, foliar)
--ZHO fungal spores although I don't like that the trichoderma spore count is so much higher than the endomychorrizal count but it was only 5 bucks for an ounce so can't beat that.
--Homebrewed Fish hydrolysates not quite sure if its done yet although it is testing out at a 4 on the ph scale, can't get an accurate reading because for is as low as the ph reading goes on the bottle, but it is two weeks in I only used the fish head, and it is still bubbling but i did just siphon out the bones today to just have the liquid sit.
--Dandelion slurry although I am a little skeptical to use this because I'm not really sure how it will affect the plant. So any opinions on that would be gladly appreciated.
-LAB culture.
Happy growing
GK

@Cann

Again, I agree and was being lazy. I use both Dolo and Calcitic, depending and should have explained my reasoning better.

Dolomite, local, ~$4+/40lb bag
Calcitic, local, ~$15/40lb bag

oyster shell flour, wherelocal, ~$15+-/40lb bag, but shipping to my AO brings that up to $45+ for that 40lb bag. Seems it's just local very close to the left coast and I'm 2,500 miles from there.

Calcitic pretty much = oyster shell flour for all practical purposes, IMO.

I mainly use the calcitic in my worm bin bedding and when I re-lime my soil garden. Dolomite is used for the initial liming but later, more Mg isn't really needed in a heavy clay soil.

In my soil mixes, I've never really noticed a buildup from the Mg in the dolo. It just seems that there is no build up due to the drainage/leaching of a peat based mix. This is in container plants, naturally.

OTOH, I never noticed much of a big deal with Mg def using calcitic. For well over 20 years I just used *screenings* of Oolitic limestone (Ancient coral seabed), in my mix. Worked great, and you just added some Epsom Salts every 2-3 months. You don't need a lot, and you don't need it often.

It's all good, whatever's cheapest and easiest available.

@GenghisKanGrow

2hrs for 1/2cup!?

Use the garden lime you have (as long as it's NOT hydrated) it's just ground up rock and farmers have been using it since they could mine/grind it. Like, before the Romans. Your problems might be from a LACK of lime, but not from using it.

The gypsum is a good add IF you have it. If not, waiting won't hurt. Took me 3 years to locate it locally.

Do a mix and get it going, you'll see what's working and what isn't.

Wet

Thanks you guys and the garden lime I bought was hydrated and fast acting so that is why i was looking for alternative sources, wanted to buy online but shipping costs for some of these weights are outrageous, so i figured if i could find a natural source might as well ya know.

Because I had a current mix that i had a lot of hope for but it was lacking in certain areas, plus i was already using bagged soil so i didn't really take into account the amendments already amended and just kind of threw my ratios in all willy nilly.

But as it is I think or am at least hoping that all will go well I have mycelia formations and am going to be infecting root systems with endo/ecto myco infection also might look into companion planting if you guys have opinions on good companion plants I was thinking about growing any type of grass.

Last question do any of you guys/gals use hygrometers when you cure? I have recently been reading up on that and it truly does seem like a pretty systematic way of curing plus you will know exactly when not to have to burp the jars anymore I might give it a go later on.

Thanks again
Happy growing

Oyster shell flour is about 95% calcium carbonate (as calcite), with traces of other minerals present. Egg shells have a very similar composition. Calcite/calcitic lime would be pure CaCO3, or more precisely one mineral form (the other being aragonite). Pure dolomite rock (dolostone) would have the stoichiometric ratio of roughly half and half Calcium to Magnesium carbonates, however, dolomitic limestone contains quite a bit less magnesium (not all of which is even available at all times to plants). The precise definition of what constitutes a "dolomitic" limestone product actually varies and is legislated (state laws differ). The term "magnesian limestone" is not widely used any more.

The exact product I use is this, labeled "Calcitic/Dolomitic". As you can see by the analysis it doesn't contain anywhere near 46% or even 30% MgCO3; it has (minimum) 12% MgCO3 corresponding to 3% actual magnesium.

So, when somebody on here is referring to dolomite they don't technically mean pure dolostone rock. They are usually just referring to dolomitic limestone or calcitic/dolomitic agricultural lime.

Found a source of crab shell meal, so i have fresh oyster shell 1/2 cup, to 1/2 cup crab meal, i also bought some gypsum, and starter mix that I might end up mixing it at a half cup ratio.

Do you guys think total of 4 cups of amendments amended is too much.
--1/3 SPM

--1/3 Wiggle worm EWC

--1:1 Perlite/Vermiculite

-1.5 cups of kelp
-1 cup of epsoma plant tone
-1/2 cup oyster shell pulverized
-1/2 cup crab meal
-1/2 cup epsoma plant tone starter with mycos
-4 cups of Azomite

IDK, you'll see after you mix it.

A quickie run down of my mix. I use a wheelbarrow and mix 2cf (15 gallons+), at a pop. Basic measurements are in 5 gallon buckets.

1 1/2 buckets (7 1/2 gallons), spag peat moss
1 bucket Perlite. I never use vermiculite, the peat moss is more than enough water retentive. You'll see for yourself if you use it.
1/2 bucket EWC. I use my own fresh castings. Much more than this and the mix turns to mud, no matter how much perlite you add I add more later as a top dressing.

For 1cf, 4 cups of Azomite is a bit much, 1-2 would be better. You aren't going to OD anything, but it will make the mix a bit heavy. Everything else looks ok.

Find some actual honest to God lime from limestone. Calcitic or dolomitic, doesn't matter, even if you don't use it in this mix have some on hand. HD or Lowes will have what you need.

I equate making a organic mix to making chili. After the basic recipe, it all depends on your taste and situation and you won't know what you need to add or leave out till you taste it.

So, get cooking!

Wet

Thanks brotha been cooking for a while and yeah I figured I would still get the rest of the amenities for the soil when its needed but for now I'm going to keep experimenting, once I use this soil I will try a completely water only grow, with one or two possible teas, and or if i can find some neem oil, I might use that and home made fish hydrolysates a little every week, or two weeks.

Thanks for the help
Happy growing
GK

Cann pretty much knocked it out of the park. Solid advice there. oyster shell and gypsum buffers my soil. no dolomite here

GenghisKanGrow said:

if i can find some neem oil

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www.neemresource.com the shipping is worth it.


also, i'd watch out with wiggle worm castings...in my experience the bags are about 50% sand...and the castings are from worms that ate cardboard and newspaper - not very nutrient dense. i'd highly recommend you look into a quality source of compost or EWC. chances are this will not come in a bag from the dro store...or a bag at all for that matter. good luck!

Cann said:

www.neemresource.com the shipping is worth it.


also, i'd watch out with wiggle worm castings...in my experience the bags are about 50% sand...and the castings are from worms that ate cardboard and newspaper - not very nutrient dense. i'd highly recommend you look into a quality source of compost or EWC. chances are this will not come in a bag from the dro store...or a bag at all for that matter. good luck!

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Yeah, $15 to ship a $10 item. I was all set to order some until I got to checkout and saw the shipping charge.

WTF!?!?

keep in mind that the $10 item is also 5lbs...most shipping is done by weight. but yeah...pretty nuts. wait till you see the shipping for their 50lb sacks hehe

st0wandgrow said:

Yeah, $15 to ship a $10 item. I was all set to order some until I got to checkout and saw the shipping charge.

WTF!?!?

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That's exactly why I make do with what's available locally. *Whatever* might be good, but seldom so good as to justify paying 2-3x as much with shipping.

The only thing I paid to have shipped this year has been kelp meal. For some reason the local feed didn't stock it. But not bad, it was $13.44/5lbs shipped and the local feed store price was $11/5lbs last year.

Wet

Cann said:

www.neemresource.com the shipping is worth it.


also, i'd watch out with wiggle worm castings...in my experience the bags are about 50% sand...and the castings are from worms that ate cardboard and newspaper - not very nutrient dense. i'd highly recommend you look into a quality source of compost or EWC. chances are this will not come in a bag from the dro store...or a bag at all for that matter. good luck!

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im down to my last 10 bags of wiggle worm (thank god) how could you tell their was so much sand? i havent seen any in the 5 pallets ive had on hand for a year. not saying u r incorrect. just wasnt looking for it

Edit maybe the sand keeps it from clumping besides the filler aspect of course. the more im thinking of the texture, the more im inclined to think its full of sand. what a waste of $$

yeah its the texture...doesn't clump like true EWC does when slightly moist...and when its bone dry and you pour it out you can see the specks of sand in there...

trash

Thanks for the replies you guys, and just found a source of crab meal as well so:

-1/2 cup oyster shell
--1/2 cup crab shell meal
---1/2 cup gypsum
----1/4 cup epsoma starter feed with mycos

Most recent things I have added to my soil besides Azomite 2-3 cups for rock dust just gotta find another aeration element thought about trying to pulverize some lava rocks but I just feel like that is going to more trouble then it is worth, found a fresh source of compost just a little skeptical of the substrates, and possible chemical lacing, etc etc

But why do you say that cutting the gypsum with oyster shell acts as a ph buffer I get the oyster shell or crab meal that you said because of Ca, but the gypsum I thought was more of a soil (sand) conditioner if you will. Correct me if I'm wrong but I was just curious can't learn unless you ask ya know.

But thanks again
And happy growing
GK

Cann said:

wait till you see the shipping for their 50lb sacks hehe

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dislike.

im gonna call directly to get a multiple bag quote. better be a steep discount!! i ordered the karanja oil neem oil and 50 lbs of the cake think i paid almost $180