I want to use lab-grade calcium nitrate in my hydroponic system (as a fertilizer) to grow lettuce, is it safe?


1 Answer 1


Usually you can buy chemicals in different purity grades. If you buy something that has the grade purum >95% will be your desired ingredient. However there is not usually any information about what the other <5% will consist of.

Personally I would never ingest (or use in food production) anything that is not food grade. Food grade does not necessarily mean very pure, it just means that there is nothing in the other x% that is potentially harmful. Look out for an FCC number, that is the Food Chemical Codex, when you order it and you should be fine.

  • $\begingroup$ Hi and welcome to chemistry.stackexchange.com. Feel free to take a tour of the site. Visit the help center for unanswered questions on how it works. $\endgroup$
    – Jan
    Jun 16, 2016 at 19:56
  • $\begingroup$ The problem is by now I do not have access to Calcium-Nitrate from stores as a fertilizer but I have access to lab-grade ones, if it has some bad thing as impurity (like heavy metals) in it does the plants absorb that or they ignore that? $\endgroup$
    – Iman
    Jun 17, 2016 at 13:40
  • $\begingroup$ You can't relay on the plant to filter out potentially harmful substances. You have no way of knowing what else is in the calcium nitrate. You could always call the supplier and ask them for more information. $\endgroup$
    – Avelina
    Jun 20, 2016 at 17:34

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