Oyster Shell as a Nutrient

Anyone ever use oyster shell and epsom salt as a substitute for cal/mag?

Oyster shell is rich in calcium and epsom has plenty of magnesium as well as sulfur.

Pros? Cons?

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Hilarious I was just talking to you about the Epsom salts in a different thread, the suggestion I have for calcium also it’s always just shells. I was told 1 tablespoon per gallon medium. I’m gonna try it out shortly but I also look forward to hearing others’ feedback.


I use epsom in flowering already, but I wondered if anyone was using oyster shell as well and considered it a cal/mag replacement. I’ve got nothing against cal/mag. It was just a thought I had.

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I used some DTE Oyster Shells as a top dress and mixed a little into the soil on a few plants. Epsom Salts are a cheap natural way to get some nutrients just make sure not to use too much and disolve some into water when watering.