Oyster shell as a calcium source?

Rasta Roy

Rasta Roy

Well-Known Member
I'm trying to leave the lime out of my next soil mix, I don't really need the pH raise. Since I won't have the lime I believe I'll need something for calcium and magnesium right? I hear oyster shell is a good source of calcium so I picked some up. Is Epsom salts my only source for magnesium? Follow up question, is the bag of Epsom salts that I have for my bathtub the same as the one I'd buy at the grow store? They both say magnesium sulfate. I've got bottles of fulvex and huvega (which I have a sneaking suspicion is the same thing as fulvex) that I can add in the water instead of the espom salts in the soil mix. But they both say derived from magnesium sulfate so it seems like it wouldn't be that different than the Epsom.

Soil mix is gonna be
50% perlite
40% sphagnum peat moss
10% compost

Amended with
Kelp Meal
Fish Bone Meal
Azomite
Oyster Shell
Gypsum

I've got Greensand I can throw in too but if I do it's a long term amendment so I don't plan on throwing in much.

Then I'm gonna top dress with worm castings and feed with guano teas when necessary (I've got a mad stock pile of subleaves guanos).

Anything I'm missing here or don't need? Is the gypsum necessary? Yay or nay to Epsom salts as a magnesium source? I've read something about it not being the best source.
 
Rasta Roy

Rasta Roy

Well-Known Member
ShLUbY said:
why are you going so light on your compost? in living soil HUMUS is pretty crucial...
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My mix I made for my current round that's in flower right now has
40% compost
20% vermiculite
40% perlite

I got good drainage. And my plants do look good, but even when they're dry they feel heavy.

I was hoping having the peat moss and less compost would give me some lighter pots so they'll be a bigger weight difference when they dry out. Also I'm hoping I'll get some faster veg growth and root development from the lighter mix.

I'm top dressing with worm castings and I'll be feeding compost teas every other week to add microbial life until the soil is alive and happy and I don't need to anymore.

Do you think I should adjust my ratio to better my soil health?
 
Rasta Roy

Rasta Roy

Well-Known Member
ShLUbY said:
I've used epsom salts plenty in soil mix, around 1/8-1/4 cup per cuft. they're a quicker release than say your crab shell will be. so once the epsom is gone the crab will help supply magnesium.

gypsum is great for extra calcium and sulfur.
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I'm not using crab meal, I got oyster shell for the calcium. Do you reapply your Epsom salts during your grow then or does it last you through your whole cycle?
 
Rasta Roy

Rasta Roy

Well-Known Member
elephantSea said:
That's what I use. I love it. and honestly, I don't even bother with any mag source other than ewc & guano teas. calcium is key.
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I'm hoping between the fish bone meal, oyster shell, gypsum, and guano I'll be covered in the calcium department! You don't bother with any magnesium sources though? Anytime I can save on ingredients I'm all about it.
 
Rasta Roy

Rasta Roy

Well-Known Member
Word! Hopefully with all the calcium sources I got going on I'll be covered and my soil will just be that much better for next time.
 
ShLUbY

ShLUbY

Well-Known Member
Rasta Roy said:
My mix I made for my current round that's in flower right now has
40% compost
20% vermiculite
40% perlite

I got good drainage. And my plants do look good, but even when they're dry they feel heavy.

I was hoping having the peat moss and less compost would give me some lighter pots so they'll be a bigger weight difference when they dry out. Also I'm hoping I'll get some faster veg growth and root development from the lighter mix.

I'm top dressing with worm castings and I'll be feeding compost teas every other week to add microbial life until the soil is alive and happy and I don't need to anymore.

Do you think I should adjust my ratio to better my soil health?
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i know what you mean about the containers feeling heavy still even when they are dry. just something you gotta get used too. it does require watering more often for sure. i may end up going 25% on my next mix with humus, we'll see. but i would say 10% is light.

Rasta Roy said:
I'm not using crab meal, I got oyster shell for the calcium. Do you reapply your Epsom salts during your grow then or does it last you through your whole cycle?
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i haven't reapplied them during, just because i feel like there'll be enough to last as i try not to let my pots get rootbound heavily. they don't need as much as they do the Ca. plus its mobile, so you'll see it in the lower big fans with green veins and yellowing if it becomes to be a problem.
 
Rasta Roy

Rasta Roy

Well-Known Member
Yeah dude, no peat at all. I read that a good quality compost would perform the same functions as peat so I figured I didn't need to waste my time. After feeling the weight difference though I've changed my mind lol. I was hoping the worm castings as a top dressing would make up for my smaller percentage of compost. But maybe I'll play around with upping the compost percentage a little closer to 20%. If I've got good compost do you think I can skip out on buying the liquid Humic acid for my compost teas?
 
ShLUbY

ShLUbY

Well-Known Member
Rasta Roy said:
Yeah dude, no peat at all. I read that a good quality compost would perform the same functions as peat so I figured I didn't need to waste my time. After feeling the weight difference though I've changed my mind lol. I was hoping the worm castings as a top dressing would make up for my smaller percentage of compost. But maybe I'll play around with upping the compost percentage a little closer to 20%. If I've got good compost do you think I can skip out on buying the liquid Humic acid for my compost teas?
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absolutely you can skip it. the people who really have it dialed in, just use water and AACT's every 4 weeks or so. that's it. i'm gonna be doing my own side by side in a couple months of 4 plants, 2 with all the tricks in the book, and 2 with just water and AACT, and record harvest, and send in for lab results just to see. why not!?!

20% should be good for compost
 
Rasta Roy

Rasta Roy

Well-Known Member
ShLUbY said:
absolutely you can skip it. the people who really have it dialed in, just use water and AACT's every 4 weeks or so. that's it. i'm gonna be doing my own side by side in a couple months of 4 plants, 2 with all the tricks in the book, and 2 with just water and AACT, and record harvest, and send in for lab results just to see. why not!?!

20% should be good for compost
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Absolutely! Experiments keep the process exciting! My current round I've got a guano amended soil mix vs traditional garden amendments mix. Then I've got one that's just compost and castings and one in just mushroom compost.

Are you gonna amend the soil of the one you're just giving water and tea too?
 
green_machine_two9er

green_machine_two9er

Well-Known Member
ShLUbY said:
absolutely you can skip it. the people who really have it dialed in, just use water and AACT's every 4 weeks or so. that's it. i'm gonna be doing my own side by side in a couple months of 4 plants, 2 with all the tricks in the book, and 2 with just water and AACT, and record harvest, and send in for lab results just to see. why not!?!

20% should be good for compost
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33% humus would be better! Like shluby says. Don't skimp on the ewc and compost. It is the most important ingredient.
 
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