|What are the percentages of nitrogen, phosphorous, potassium in ordinary backyard dirt?
Those percentages vary greatly from one soil to another. A soil's parent material (what it came from) and fertilizing history will affect its current nutrient content. Your County Extension Office can assist you with having your soil tested and interpreting the results. That is the only way to know for sure what nutrient levels your soil contains. Their number is 864-232-4431.
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