Can you find its ingredients on the Internet or on a label? (Ordinarily, I'd do this for you, but cannot do it today. Sorry....)
I haven't used it, but many of us can often read the ingredients and give you an idea about the safety of a product. There's also a Materials Safety Data Sheet (MSDS) you can look up. The key words are often (for example) "Espoma MSDS."
Sunset Zone 17, USDA Zone 9