Crushed oyster shells

[MadScientist]

Has anyone used these for mineral supplements in the garden? I see 50# bags available for chicken feed--would this be beneficial for general tomato nutrients or against BER?

[Nematode]

Maybe for the next guy. I dont think the calcium is available for a very long time.
Tiny bit of N available .36-0-0
http://www.lundproduce.com/N-P-K-Val...verything.html

[RayR]

Oyster shell is almost entirely made of Calcium Carbonate which is just like Calcite Lime.
It would be a long term source of calcium in the soil but if your soil is already very alkaline then you already have more than enough calcium carbonate in your soil so wouldn't need it or want it because it may increase soil PH even further.
For very acidic soils it would be a benefit.

[Gardeneer]

Originally Posted by RayR

Oyster shell is almost entirely made of Calcium Carbonate which is just like Calcite Lime.
It would be a long term source of calcium in the soil but if your soil is already very alkaline then you already have more than enough calcium carbonate in your soil so wouldn't need it or want it because it may increase soil PH even further.
For very acidic soils it would be a benefit.

Same as eggshell ?.
For immediate release of Calcium ( Ca++) add vinegar to it.
What you will get is "Calcium Acetate" in which Calcium is in ionic form ( Ca++) and available for plants .
I don't know what other elements are there in oyster shell.
The reason for selling is as chicken feed is to provide calcium for the birds for it eggshell. I am sure some of the Calcium Carbonate in oyster shell is released in the gizzard of the birds by some kind of acid. Some of it might end up in chicken poo too.

[bower]

I toss a lot of shells in my garden, with the idea that eventually it will make a source of calcium for plants because we have no calcium in our soil here and very acid conditions. That being said, there's no sign that shells break down readily. I toss mussel shells in the paths and tromp them down to keep the weeds at bay. I have a few oyster shells (whole) that I used to make a broth one time my son was sick when he was little so maybe... 20 years ago? No, 25 or more years ago (where does the time go? why are my math skills worsening? ) Anyway, the oyster shells that were boiled in the first place were afterwards tossed in the garden.. several of them are still about and intact for all intents and purposes. I did pick one up in recent years and it was foundered enough I could snap it. But there is little to be had there from a rapid nutrient perspective, IMO. Maybe for tree planting, if they're long lived.
If I had access to oyster shells crushed as you said in a 50 lb bag, I would probably use it as a landscaping material in my paths, make a nice weed suppressing surface.

[RayR]

Same here bower, I remember when I first dug up part of my lawn for the garden, I found practically intact clam shells and oyster shells that some previous owner of the property put there. God knows how long ago that was.
With anything made of insoluble carbonates like oyster shells, egg shells, or limestone, the finer it's ground into a powder the greater the surface area that will be exposed to chemical weathering (acids in the soil) and microbial mineralization.