The 2018 Farm Bill made a significant change to the definition of “marijuana” by introducing a THC threshold. Specifically, it now requires a concentration of at least 0.3% Delta-9 THC on a dry weight basis for something to be considered marijuana. In simpler terms, if a plant—or any product derived from it—contains 0.3% Delta-9 THC or less, it’s not classified as marijuana and therefore, not illegal to possess.

What Does “Dry Weight Basis” Mean?

“Dry weight basis” might sound a little technical, but it’s pretty straightforward. It refers to measuring the concentration of a substance (in this case, Delta-9 THC) after all the moisture has been removed. Why does this matter? Because water content can vary, and by removing it, you’re left with a consistent measure of the actual material, allowing for accurate comparisons between samples.

Cool, But How About a Real-World Example?

Let’s say you’re looking to create a THC-infused drink with 5mg of Delta-9 THC in it. What would the dissolved solids need to weigh to stay within the 0.3% threshold?

Here’s the math:

TOTAL DRY WEIGHT = (5mg THC ÷ 0.003) = 1,666.67 mg, or about 1.67 grams of dissolved solids.

So, for that 5mg of THC to be compliant, the total dry weight of the drink must be at least 1.67 grams.

Does the 0.3% Rule Apply to Just the Plant, or Everything Made From It?

Now, here’s where people often get tripped up. Does the 0.3% Delta-9 THC threshold only apply to the hemp plant in the field, or does it apply to anything made from the plant? There are two schools of thought on this—and only one of them is correct.

The Wishful Thinking Approach:

Some people like to believe (or wish) that if the plant itself was under the 0.3% threshold, anything derived from that plant is automatically compliant. In this line of thinking, you could theoretically extract from 100 compliant plants and concentrate the THC far beyond 0.3%—all while still claiming the product is legal. This, however, doesn’t fly under the 2018 Farm Bill, Wisconsin statutes, or even common sense.

Why would lawmakers apply the 0.3% rule to plants, but not the products derived from them? It wouldn’t make sense. The intent is clearly to limit THC concentration, not to allow super-concentrated extracts just because the raw plant was compliant.

The Correct Interpretation:

Both the plant and anything derived from the plant must adhere to the 0.3% Delta-9 THC threshold. If your extract or drink exceeds this limit, it’s not compliant, even if the original plant was.

What Does This Mean for You?

  • Consumers: Be aware that many products currently on the market are not compliant. Some producers operate under the incorrect assumption that the original plant’s compliance means they can concentrate THC beyond the legal threshold.
  • Producers: Ensure that all your products meet the 0.3% threshold, not just the plants you grow. Make sure the lab you’re using tests based on dry weight rather than just “weight” alone. This is a common mistake that can easily lead to non-compliance.

Thanks for reading.