Most growers know the N-P-K numbers on fertilizer, but that doesn't tell you what else might be in the material, either as a contaminant or something purposely added to the material.  CA Department of Food and Agriculture has a website that according to manufacturer and material there is a full listing of what is in the product.  The website is: http://apps4.cdfa.ca.gov/fertilizerproducts/

What's startling is the shear number of producers on the market

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