Understanding Hemp Compliance: Meeting USDA Testing Standards

The latest USDA hemp testing standards indicate growers must submit samples for THC potency analysis. Meeting federal hemp testing requirements also means hemp growers must work with qualified laboratories.

This article details the 2024 USDA hemp testing rules and examines potential changes in the upcoming Farm Bill legislation that could impact hemp legality and testing.

‍

USDA Testing Standards for Hemp

The official USDA testing rules were released as part of the 2021 Final Rule for the Domestic Production of Hemp, which set standards for THC potency testing in hemp crops, sample collection, and the testing timeline.

‍

What are the USDA requirements for THC levels?

USDA testing rules require that hemp producers test pre-harvest samples to measure the total content of delta-9 tetrahydrocannabinol (THC), the primary intoxicating component of cannabis. Hemp contains high quantities of THC’s precursor, THCA, so USDA testing must also account for this compound, which converts to THC through heat exposure.

The rules state that hemp’s Total Delta-9 THC, calculated by the equation Total THC = Δ9-THC + (THCA × 0.877), cannot exceed 0.3% by dry weight (USDA, 2021, p. 5614).

Hemp testing labs must also estimate and report the THC measurement uncertainty (i.e., the margin of error) for each test result to ensure the potency remains within a reasonable limit. 

‍

Sampling process and timeline

Under the USDA Final Rule, hemp producers must collect samples for compliance testing up to 30 days before the anticipated harvest. “Samples” refer to collecting cuttings from the flower material of hemp plants.

‍

• Sample method: Hemp producers should take samples approximately 5 to 8 inches from the “main stem” (includes the leaves and flowers), “terminal bud” (occurs at the end of a stem), or “central cola” (cut stem that could develop into a bud) of the flowering top of the plant. 
• Representation: Samples should represent a homogeneous composition of the lot they come from.
• Sample size: There should be enough samples collected to ensure at a confidence level of 95% that no more than 1% of the plants in the lot would exceed the acceptable hemp THC level.

‍

Why growers should test early

According to research conducted at Cornell University, many strains can accumulate total THC content above the 0.3% limit before they reach maturity, and THC concentration in hemp generally increases the longer the plant is in the ground. Testing samples early and often ensures compliance with federal hemp rules. Producers can also correct potential errors before wasting time and money on a contaminated batch. 

‍

Lab Requirements for USDA Testing Rules

Hemp growers and brands must work with hemp testing laboratories that meet specific requirements to qualify under USDA testing rules. 

‍

• Any laboratory testing hemp for THC concentration under the U.S. Domestic Hemp Production Program must be registered with the Drug Enforcement Administration (DEA) to handle controlled substances by December 31, 2025. 

• The USDA strongly encourages hemp testing laboratories to have International Organization for Standardization (ISO) accreditation; however, this is not required. 

• Labs must follow specific protocols, with or without ISO accreditation, to ensure reliability and consistency in their testing methods. 

‍

ACS Laboratory exceeds every USDA testing laboratory requirement and recommendation. It is a DEA-registered facility that follows ISO/IEC 17025:2017 accreditation standards. 

‍

Acceptable methods for measuring THC content

According to the USDA, hemp laboratories must calculate the total THC using post-decarboxylation or a similarly reliable method. Gas chromatography (GC) and high-performance liquid chromatography (HPLC) are the gold-standard methods.

‍

• Gas chromatography applies heat to the sample, which decarboxylates THCA, producing delta-9 THC. Thus, the final delta-9 THC result is the total THC. 

• High-performance liquid chromatography does not involve significant heat, meaning the THCA in a sample does not generally decarboxylate. With this method, labs determine THCA and delta-9 THC separately and report the values together post-testing.

Risks Associated with Non-Compliant Hemp

Hemp producers face financial consequences for producing crops whose THC concentration range exceeds 0.3% THC. The USDA Final Rule states that producing non-compliant plants falls under a “negligent” violation.

‍

Growers will not face criminal charges for this offense. However, cannabis exceeding the legal 0.3% total THC level constitutes marijuana, a Schedule I controlled substance. Thus, hemp producers must mitigate the issue in one of the following ways:

‍

• Dispose of the material following the Controlled Substance Act and DEA regulations.
• Perform “remediation” activities, if possible, to reduce the total THC percentage. 
• Salvage the remainder of the plant by blending it into biomass plant material.

‍

Remediation attempts can help minimize financial loss. However, producers whose hemp fails USDA compliance testing will likely lose most of the economic value of their investment. In addition, hemp producers who commit three negligent violations in five years risk losing their license for at least five years.

‍

Potential Changes to the Farm Bill

Congress must approve a new federal farm bill every five years, and the upcoming 2024 Farm Bill draft includes changes that could affect hemp farmers, testing rules, and the types of hemp cannabinoid products considered lawful under USDA’s hemp program. 

‍

• Industrial hemp: A new statutory definition of industrial hemp (such as grown for fiber) would relax some regulatory requirements for this hemp type only, possibly reducing or even eliminating testing for THC.

• Intoxicating cannabinoid ban: Another amendment would specify that hemp only includes “naturally occurring, naturally derived, and non-intoxicating cannabinoids.” This definition would prohibit hemp cannabinoid products with “quantifiable amounts” of total THC beyond just THCA to any other cannabinoids that have (or are marketed to have) “similar effects on humans or animals” as THC (such as popular alternative cannabinoids like Delta-8, Delta-10, and HHC). Such a ban would drastically reduce demand for industrial hemp flower. 

‍

These changes will also likely entail stricter federal hemp testing requirements, possibly requiring labs to quantify other compounds to meet a more refined definition of hemp. 

‍

Hemp Testing with ACS Laboratory Ensures USDA Compliance

‍ACS Laboratory is a USDA-approved lab that uses sophisticated testing protocols to guarantee hemp producers meet regulatory standards. 

‍

• ACS is an ISO/IEC 17025:2017 Accredited by A2LA #6786.01 laboratory that is federally approved for its hemp testing methods. 
• The lab is a DEA-registered laboratory aligned with USDA  hemp guidelines.
• During compliance testing, ACS employs gold-standard Ultra-High-Performance Liquid Chromatography (UHPLC) and Gas Chromatography-Mass Spectrometry (GC-MS) techniques. 
• ACS Laboratory is a registered hemp testing laboratory in Florida, FL, Louisiana, Utah, Colorado, Arkansas, Texas, Tennessee, and Georgia.

‍

ACS also guides Florida hemp growers through the sample collection process, picking up samples from local Farms. 

‍

Pre-compliance testing with ACS

In addition to testing THC potency for compliance, ACS Laboratory assists hemp growers with research and development (R&D) tests during pre-planting and pre-harvest phases, including:

‍

• Soil tests for heavy metals (lead, cadmium, arsenic, mercury), pesticides, and other chemical agents

• Micronutrient testing, which pinpoints mineral deficiencies and ensures healthy growth and development
• Cannabinoid profiling measures THCA and CBDA, the acidic forms of these cannabinoids that contribute significantly to total THC and CBD levels.

‍

The Bottom Line

Hemp growers must follow USDA and state testing rules for compliance testing to avoid costly crop losses and potential license restrictions. The best way to monitor total THC levels is to partner with a qualified lab to test hemp plants early and often throughout the growth cycle. 

‍

Contact ACS Laboratory for guidance on collecting and submitting samples for compliance testing that exceeds federal hemp testing requirements.