Best ratio of gypsum/epson salts?

nygaff1

Well-Known Member
I grow in an organic soil media in earthboxes. My water is softened, so I use RO to remove the sodium chloride. Up until this last round I have always used OptiVeg for calcium and 1/4tsp/g of epson maybe once in 7-10days. I was running into calcium deficiencies in early-mid flower so I figured I needed another source of calcium. I started adding a bit of oyster shell flour to my top dress as well as the occasional drench and res fill with ag gypsum.

The problem is, I feel like I am approaching this a bit too much like cooking in the analogy of cooking being an art vs baking a science. I've read totally different rations of mag:cal, from 5:1 to 7:1? What should I be aiming for here?

Also, when referring to these different ratios, are they referring to mass or to volume? If it is mass, gypsum is not pure calcium. How would I calculate that?
 
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