USDA THC Testing Guidelines


For states that grew hemp in 2018, identify their rate of failure for hemp samples testing above the 0.3% THC concentrate limit.

Early Findings

North Carolina

  • In 2017, 135 hemp samples were tested within the state and 14 tested above 0.3% THC
  • In 2018, about 400 samples were tested and 38 came back positive.
  • Thus, around 10% of samples are testing as "hot hemp," the term used to describe hemp over the 0.3% limit.


  • The average rate of failure by testing over 0.3% THC for hemp samples in Colorado is 30%.


  • Washington State was using a different process to test hemp up until October 31, 2019. The state tested the entire plant, instead of just a top clipping like other states do. With testing the entire plant, state officials said virtually everyone passed. One sample did fail, but was retested at a different lab and passed.
  • Farmers in Washington are concerned that more people will fail with the new rules, which also decrease the testing time frame from 30 days prior to harvest to 15 days.

Proposed next steps:

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As the initial research was only able to cover three states, we recommend further research into the additional 21 states ( that grew hemp in 2018 their current rate of failure for hemp samples testing above the 0.3% limit. This may be presented as a percentage, or by the actual total number of samples and number of failures in the most recent year available. Additionally, for each state, we will summarize their testing requirements, including when the crop needs to be tested, who pays the testing fee and how much it is, and finally, what happens to samples that test over the limit.
Additionally, our research indicated that the FDA has just released new rules regarding THC testing for hemp. We propose a review, including 7-10 insights, on these new rules and the responses (2-3 positive and 2-3 negative) to them.