What are you ‘allowed’ to use in CERTIFIED ORGANIC farming?

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Question by barefootwanderin: What are you ‘allowed’ to use in CERTIFIED ORGANIC farming?
What would the people who buy organic goods be surprised that farmers/producers can use on compost, the land, the crop?

If you have good reason there are other non organic substances you can use in certified organic farming. What are these? Have you used them?

Is organic, really organic?

Can you help? Leave your own answer in the comments!