Hey guys and gals, after reading about the benefits of crushed oyster shells for organic gardening I've decided to start implementing them into my compost and grow mixes. I have an untold amount of them buried in the edge of the woods on my property where we used to chuck them after an oyster party.(Down here that's just an old beer drinking and oyster shucking session). Anyhoo, my SS Chronics are ready to be put into their final pots for flowering, but before I do I want to add a bit of crushed shells. I've already crushed up some and the older ones powder up pretty nicely. How much do I need per gallon of soil? Also, will the larger fragments be beneficial to the tilth of the soil?