The 2018 Farm Bill legalized hemp nationwide, establishing federal oversight of hemp cultivation throughout the US. However, the bill did not address quality control testing throughout the growth cycle or final product testing. To fill this gap, several states created their own hemp programs with regulations for final product testing. Most states, however, still follow the Farm Bill and lack specific oversight for finished goods. This void leaves many brands uncertain about when and how to test their hemp to ensure optimal quality.
This article details a complete hemp testing timeline, covering when and how to test hemp at all stages of growth and production for compliance and quality.
Federal Hemp Testing Regulations
The USDA's hemp testing regulations, released as part of the 2021 Final Rule for the Domestic Production of Hemp, set clear standards for pre-harvest THC potency testing. The Final Rule requires that plant samples be tested within 30 days of harvest and must not exceed the threshold of 0.3% total Delta-9 THC on a dry weight basis. The testing methodology must account for both THC and THCA (which converts to THC through heat ), ensuring accurate measurement of the concentration.
By 2025, all testing must be conducted by DEA-registered laboratories, with some flexibility for states and tribes with their own federally approved hemp programs. Laboratories are not required to be ISO accredited but must follow specific protocols to ensure reliability and consistency in their testing methods. Labs are required to estimate and report measurement uncertainty with each test result.
If a grower's hemp samples fail the THC test, the crop is deemed non-compliant and must be destroyed.
State Hemp Testing Regulations
In addition to federal pre-harvest testing requirements, hemp brands must navigate a complicated web of state testing regulations that vary across the country and change constantly. Many states have rules about how and where to test, how to verify the results, and how to label and package the final product.
For instance:
- Indiana, Texas, Utah, Florida, New York, and Oregon have all made it mandatory to include a QR Code linked to a Certificate of Analysis (COA) for potency and ingredient information on hemp product labels.
- The Colorado Department of Agriculture introduced new rules for inspecting unfinished hemp flower and ramped up contaminant testing to include 102 harmful pesticides.
- Florida recently added contaminant requirements for smokable hemp products.
State testing rules also typically require third-party labs to invest in highly sensitive machinery to ensure the accuracy of their results. Their methodology must detect trace levels of all contaminants, including residual solvents, microbiology, mycotoxins, moisture and water sensitivity, and additives like vitamin E.
State hemp-derived cannabinoid rules
Many states have also enacted restrictive testing rules concerning hemp-derived cannabinoids, like Delta 8, Delta 10, and THCP. Such regulations mandate that laboratories add these alternative cannabinoids to the calculation when determining total THC concentration and whether products adhere to the 0.3% limit. Other states ban these hemp-derived compounds altogether.
Hemp brands must be aware of state-by-state rules and consider submitting samples to ACS Laboratory’s National Hemp Compliance panel to comply with most regulations.
Hemp Testing Timeline
So, when is the right time to start testing hemp, and how can growers and producers ensure that the product will be safe, compliant, and effective for consumer use?
ACS Laboratory, a leading provider of cannabis, hemp, and CBD testing services, recommends starting the process early to ensure plants and products are potent (within legal limits) and pure. Hemp producers that test early and continue testing throughout hemp’s growth cycle can correct potential errors along the way before wasting time and money on a contaminated batch.
First Testing Phase for Growers: Pre-Planting
Before planting hemp, testing the soil is crucial.
Hemp is known for absorbing toxic elements from the ground, which can lead to contaminated final products like flower, oils, or isolates. Heavy metals such as lead, cadmium, arsenic, and mercury are among the most dangerous. Exposure to these metals can result in severe health conditions, including kidney damage, vomiting, low blood pressure, and seizures.
A recent federal lawsuit highlighted that CBD products frequently fail heavy metal tests, presenting significant risks to consumers and businesses.
To avoid these issues, the grower can submit samples for pre-planting tests, including:
- Heavy metals (lead, cadmium, arsenic, mercury)
- Pesticides
- Other chemical agents
- Soil testing helps ensure a safer growing environment and reduces the chances of contaminated hemp products entering the market.
Second Testing Phase for Growers: Pre-Harvest
Pre-harvest testing is critical for ensuring compliance and quality.
Compliance
Research conducted at Cornell University revealed that as hemp flower grows, the plants can accumulate illicit THC levels before they reach maturity. To ensure their crop remains viable, growers must consider sending samples for pre-compliance potency testing within the first several weeks after flowering tops appear.
Growers must then follow state and federal guidelines for pre-harvest THC testing.
- Most regulations require growers to send samples 15 to 30 days before harvest for potency analysis.
- Growers must send the samples from every plot to ensure all are compliant
- Some states, like Florida, require that a laboratory representative go onsite and clip hemp samples for testing.
Quality
ACS Laboratory also offers various R&D testing options in the pre-harvest phase, including:
- Micronutrient testing, which pinpoints mineral deficiencies and ensures healthy growth and development
- Cannabinoid profiling, such as measuring THCA and CBDA, CBN and CBG.
Third Testing Phase for Growers & Processors: Post-Harvest
Post-harvest testing ensures plant safety and determines effects, flavor, and fragrance profile.
Post-harvest testing occurs after growers trim away hemp leaves, roots, and stems before they sell the plant as a smokable flower or make it into hemp extract-based products. At this point, brands must complete safety screenings and measure compounds that determine effects.
Safety
Post-harvest safety tests detect:
- Moisture levels, one of the critical factors that can indicate risk for contamination and make plant material unsuitable for extraction
- Pesticides, which can harm humans and can’t exceed the Department of Health’s accepted pesticide limitations per Statute 381.986
Chemical Profile
Post-harvest profiling tests include:
- Terpene profiling and potency measure the essential oils interacting with cannabinoids to impact a product’s therapeutic profile significantly.
- Flavonoid testing measures compounds important for preserving plant pigments, flower coloration, taste, smell, and the overall sensory experience.
Experts at ACS Laboratory can work with growers and brands to receive samples for their post-harvest testing needs..
Fourth Testing Phase for Processors: Post-Extraction
Post-extraction tests look for dangerous compounds that can compromise finished products. They also examine potency levels.
Innovations in extraction and filtration technology (like sub-zero methods versus heat) have allowed brands to optimize a more extensive range of extract-based products, such as:
- Cannabinoid topicals targeted toward location-specific relief
- Skincare products, like CBD lotions, serums, lip balms, and even bath bombs, are catching on among younger consumers through social media
- Softgels, liquid capsules, and gel caps often paired with vitamin C, ginkgo biloba, and other natural substances with nutritional or therapeutic value
Safety
However, the extraction process involves liquid gas solvents that can harm consumers if not removed entirely. Post-extraction testing examines hemp extract-based products for quality and safety, looking for:
ACS tests for 21 different solvents along with a complete microbiological analysis using state-of-the-art technology to provide swift and accurate results.
Potency
ACS laboratory offers extensive cannabinoid profiling tests for hemp and hemp-derived products.
- ACS Laboratory tests up to 32major, minor, and alternative cannabinoids.
- THC potency testing methods accurately distinguish Delta-8, Delta-9, and Delta-10 levels
Fifth Testing Phase: Post-Production
Post-production testing confirms that final products are safe, compliant, and potent.
At this stage, brands must work with qualified laboratories to tailor post-production testing to the final product type. For instance, edibles, beverages, and nanoemulsion products have unique needs compared to hemp topicals and extracts.
Post-production tests often include:
- Cannabinoid profiling identifies the exact concentrations of THC and CBD for federal and state compliance, along with other minor and alternative cannabinoids in broad- and full-spectrum products.
- Shelf life and stability tests establish expiration dates and optimize storage and packaging.
- Homogeneity testing for edibles like hemp gummies, chocolates, and candies confirms consistent potency throughout the product for accurate dosing.
- Cannabis beverage testing confirms safety and stability in water-based drinks, which are highly susceptible to bacteria growth and pH imbalances.
- Heavy metals analysis, including ACS Laboratory’s HHC Heavy Metals Testing Bundle, examines four additional analytes, platinum, cadmium, nickel, and zinc, that could be introduced during production.
These tests ensure final products have accurate labels for legal sales, with testing results verified in the official COA (certificate of analysis). These tests also give consumers the information they need to choose a product that’s right for their bodies and conditions.
Hemp Testing With ACS Laboratory
ACS Laboratory uses gold-standard testing protocols, including Ultra-High-Performance Liquid Chromatography, Inductively Coupled Plasma Mass Spectrometry for detecting heavy metals, and Gas Chromatography-Mass Spectrometry (GC-MS) equipment. These techniques guarantee the accuracy of results.
ACS Laboratory is ISO/IEC 17025:2017 Accredited by A2LA #6786.01 is compliant with multiple state hemp testing programs. It is also a DEA-registered laboratory.
ACS Laboratory crafted a National Hemp Testing Panel to support brands in an uncertain regulatory environment to align with the strictest standards for potency, pesticides, residual solvents, additives, and all dangerous contaminants. Hemp testing with ACS Laboratory is the most comprehensive in the industry, detecting numerous compounds, including:
- Up to 32 cannabinoids
- 105 pesticides
- 24 heavy metals
- 55 potential residual solvents
- 17 different microorganisms
- Every required mycotoxin
- Moisture content
- Water activity
- Terpenes (upon request)
The Bottom Line
Thorough hemp testing is the best way for businesses to meet stricter requirements for the expanding product market. To learn more about how and when to test hemp from pre-planting to post-production, contact ACS online or call (813) 634-4529.
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