Congress Redefined Hemp in 2025: What USDA Farm and Poison-Center Data Show

In November 2025, Congress rewrote the federal definition of hemp. The new definition counts total THC, not only delta-9 THC, and excludes final hemp-derived cannabinoid products that contain more than 0.4 milligrams of total THC and similar cannabinoids per container. Over the five growing seasons the U.S. Department of Agriculture has measured, the value of hemp grown in the open went from $712.2 million in 2021 to $212.3 million in 2022, then to $645.8 million in 2025. The 2025 crop was planted before the law was enacted. Poison centers recorded 4,925 delta-8 THC exposures in 2021 and 2022, and the national exposure rate rose from 0.53 to 0.95 per 100,000 people between those two years.

The new definition does not take effect all at once. Its general effective date is 365 days after enactment, but a September 2026 law limits it to certain products until December 11, 2026. This article sets out what the two laws say, what the farm data and poison-center data show, and what those numbers cannot tell you. It reflects the law as of October 26, 2026.

What the 2018 Farm Bill said

The Agriculture Improvement Act of 2018 (Public Law 115-334), signed December 20, 2018, set the federal definition of hemp in Section 10113. The test turned on one compound, delta-9 THC.

"'hemp' means the plant Cannabis sativa L. and any part of that plant, including the seeds thereof and all derivatives, extracts, cannabinoids, isomers, acids, salts, and salts of isomers, whether growing or not, with a delta-9 tetrahydrocannabinol concentration of not more than 0.3 percent on a dry weight basis."

The definition included "derivatives, extracts, cannabinoids, isomers" and set a cap on delta-9 THC only. It did not name other THC compounds, such as delta-8 THC. Some states wrote their own rules. A 2024 study in the Journal of Medical Toxicology reported that 15 states had banned delta-8 THC and 9 more had restricted it.

What Congress changed in November 2025

Public Law 119-37 (H.R. 5371), a continuing appropriations act, was signed November 12, 2025. Section 781 of Division B amends the hemp definition in Section 297A of the Agricultural Marketing Act of 1946 (7 U.S.C. 1639o).

The amended definition caps total THC rather than delta-9 alone. It covers plants and products "with a total tetrahydrocannabinols concentration (including tetrahydrocannabinolic acid) of not more than 0.3 percent on a dry weight basis."

It also lists products that are not hemp. Paragraph (iv) excludes any final hemp-derived cannabinoid product containing:

"(I) cannabinoids that are not capable of being naturally produced by a Cannabis sativa L. plant; (II) cannabinoids that-- (aa) are capable of being naturally produced ... and (bb) were synthesized or manufactured outside the plant; or (III) greater than 0.4 milligrams combined total per container of-- (aa) total tetrahydrocannabinols (including tetrahydrocannabinolic acid); and (bb) any other cannabinoids that have similar effects (or are marketed to have similar effects) on humans or animals as a tetrahydrocannabinol (as determined by the Secretary of Health and Human Services)."

A "container" is "the innermost wrapping, packaging, or vessel in direct contact with a final hemp-derived cannabinoid product in which the final hemp-derived cannabinoid product is enclosed for retail sale to consumers, such as a jar, bottle, bag, box, packet, can, carton, or cartridge." The section also excludes intermediate products "which are marketed or sold as a final product or directly to an end consumer for personal or household use."

Section 781 directed the Food and Drug Administration to publish, within 90 days of enactment, a list of cannabinoids known to FDA to be capable of being naturally produced by the plant, among other items. This article did not check whether or when FDA published them.

The effective dates, in the laws' own words

Section 781 opens: "Effective 365 days after the enactment of this Act." Counting from November 12, 2025, that date is November 12, 2026.

On September 2, 2026, the Continuing Appropriations and Extensions Act, 2027 (Public Law 119-103, H.R. 6500) was signed. Its Section 2019 reads in full:

"Until December 11, 2026, the amendments made by section 781 of division B of Public Law 119-37 (7 U.S.C. 1639o note) shall only apply with respect to products described in paragraphs (1)(C)(ii)(I) and (1)(C)(iv)(I) of section 297A of the Agricultural Marketing Act of 1946 (7 U.S.C. 1639o) (as amended by such section 781)."

Paragraph (1)(C)(iv)(I) is the final-product item quoted above, covering cannabinoids "not capable of being naturally produced by a Cannabis sativa L. plant." Paragraph (1)(C)(ii)(I) is the parallel item for intermediate hemp-derived cannabinoid products containing cannabinoids "not capable of being naturally produced by a Cannabis sativa L. plant." Section 2019 does not describe the products in plain terms beyond those cross-references, and its limit runs "until December 11, 2026."

How these provisions apply to a particular product, and on which date, is a question for the agencies and the courts. If you sell or buy hemp-derived THC products, check current USDA and FDA guidance, and your state's rules, before relying on any date. Congress can change these dates again, and this article will be updated if it does.

How the September 2026 law passed

The votes were on the whole appropriations bill except the 61-32 vote, which was on the motion to table the Budd amendment. Budd's amendment would have removed Section 2019.

What happened to U.S. hemp farming

USDA's National Agricultural Statistics Service (NASS) began its National Hemp Report with the 2021 crop. Its figures cover all hemp, whether grown for flower, fiber, grain or seed, and they measure value at the farm, not retail sales.

Value of U.S. industrial hemp utilized production grown in the open, as first published each year. Source: USDA NASS National Hemp Report (2023 later revised to $285.9 million, 2024 to $420.9 million).

The 2023 value was first published as $258.2 million in April 2024. The April 2025 report revised it to $285.9 million, and NASS measured the 2024 increase against that revised figure. The April 2026 report revised the 2024 value from $416.7 million to $420.9 million and measured the 2025 increase against that revised figure. This article shows each year as first published and gives the revised figures alongside.

Hemp grown under protection, such as in greenhouses, is reported separately. NASS put its value at $111.9 million in 2021, $32.9 million in 2023, $28.7 million in 2024 and $93.3 million in 2025.

U.S. hemp acres planted and harvested in the open, as first published each year. Source: USDA NASS National Hemp Report.

Planted acres fell 47.7% from 2021 to 2022, rose 63.6% from 2023 to 2024 and rose 9% in 2025. The 2021 through 2024 crops predate the 2025 law. The 2025 crop was planted before the law was enacted on November 12, 2025, and Section 781 had not taken effect during that season, so the 2025 figures cannot be read as a response to the law. The NASS reports do not split hemp by end product, so they cannot show how much of the crop went into delta-8 or other intoxicating products.

What poison centers recorded

Poison centers began coding delta-8 THC exposures separately in 2021. In a September 14, 2021 health advisory, the Centers for Disease Control and Prevention reported 660 delta-8 exposures under the new code from January 1 to July 31, 2021. Of 661 cases it counted, 18% (119) required hospitalization and 39% (258) involved patients under 18.

A study by Smith and colleagues, published in the Journal of Medical Toxicology in 2024, counted 4,925 exposures with delta-8 THC as the primary substance in 2021 and 2022. It found 69.8% of them were reported in the South. The national rate rose 79.2%, from 0.53 per 100,000 people in 2021 to 0.95 in 2022.

The study also grouped states by their delta-8 policy before January 1, 2023, and averaged each group's state rates.

Delta-8 THC poison-center exposures per 100,000 population, mean of state rates, by state delta-8 policy as of Jan. 1, 2023. Source: Smith et al., Journal of Medical Toxicology, 2024 (National Poison Data System). An association; states differ in other ways.

States that had banned delta-8 had lower average rates in both years. The same study found a similar gap by cannabis policy: in 2022, states where cannabis was illegal averaged 1.64 delta-8 exposures per 100,000 people, and states where it was legal averaged 0.52. Because state policies on delta-8 and on cannabis overlap, and because states differ in population, reporting habits and regional markets, the comparison does not show that a ban caused a lower rate.

In the study's data, 40.5% of exposures involved people aged 20 to 59, 30.4% involved children under 6 and 24.4% involved people aged 6 to 19. Ingestion accounted for 94.3%.

America's Poison Centers states on its tracking page that poison centers managed 10,434 delta-8 THC related exposure cases from 2021 to 2025. That count covers delta-8-related cases and is not on the same basis as the study's primary-substance count. Year-by-year counts after 2022 were not available in a form we could verify.

How we measured

Law. Statute text comes from the enrolled public laws on congress.gov (Public Law 119-37 and Public Law 119-103) and govinfo.gov (Public Law 115-334). Vote counts and dates come from the Congress.gov pages for H.R. 6500 and Senate Amendment 6747 and the House Clerk's record of Roll Call 286. We quote the operative text rather than summarize which products fall under which date, because that application is not settled by the text alone.

Farm data. Hemp acreage and value come from the USDA NASS National Hemp Reports for crop years 2021 through 2025, published February 2022, April 2023, April 2024, April 2025 and April 2026. We use each year's figure as first published, and note the revisions to the 2023 value (April 2025) and the 2024 value (April 2026). The survey design changed between years: the 2021 report drew on a sample of 20,501 surveyed in October to December 2021, and the 2024 report on a sample of 8,153 surveyed in February and March 2025. Values are farm-gate value of utilized production for all hemp uses. They are not retail sales and do not separate delta-8 or other intoxicating products. NASS data before the 2021 crop were not used.

Poison-center data. Exposure figures come from the CDC's 2021 health advisory, from Smith et al. (2024), which analyzed National Poison Data System records for 2021 and 2022, and from the America's Poison Centers tracking page. Poison-center counts are calls about exposures, not a measure of how many people use delta-8. The delta-8 product code began in 2021, so there is no earlier baseline. The policy-group rates are unweighted averages of state rates, and the policy groups reflect state law before January 1, 2023.

What the data cannot show. No audited estimate of the retail delta-8 or intoxicating-hemp market was found, so none is given here. We did not retrieve a current state-by-state count of delta-8 bans and restrictions, or poison-center comparisons by state policy for 2023 or later. The farm data end with the 2025 crop, which was planted before the law was enacted on November 12, 2025. The study data end with 2022.

Frequently Asked Questions

When does the federal hemp redefinition take effect?

Section 781 of Public Law 119-37 says it is effective 365 days after enactment; the law was signed November 12, 2025. Section 2019 of Public Law 119-103, signed September 2, 2026, says that until December 11, 2026, the amendments shall only apply with respect to products described in paragraphs (1)(C)(ii)(I) and (1)(C)(iv)(I) of the amended definition. Check current USDA and FDA guidance for how this applies to a specific product.

What is the 0.4 milligram limit?

The amended definition excludes from hemp any final hemp-derived cannabinoid product containing more than 0.4 milligrams combined total per container of total THC (including THCA) and other cannabinoids with similar effects, as determined by the Secretary of Health and Human Services. A container is the innermost packaging in direct contact with the product, such as a jar, bottle, bag, packet or cartridge.

How did the 2018 Farm Bill define hemp?

Public Law 115-334, signed December 20, 2018, defined hemp as Cannabis sativa L. and its derivatives, extracts, cannabinoids and isomers with a delta-9 THC concentration of not more than 0.3 percent on a dry weight basis. The 2025 law changes the measure to total THC, including THCA.

How big is the delta-8 market?

We did not find an audited figure for retail sales of delta-8 or other intoxicating hemp products, so this article does not give one. USDA reports farm-gate value for all hemp grown: $645.8 million for hemp grown in the open in 2025, as first published. That figure covers every hemp use, not only delta-8.

Do state delta-8 bans reduce poison-center calls?

A 2024 study in the Journal of Medical Toxicology found that, in 2022, states that had banned delta-8 averaged 0.17 exposures per 100,000 people and states with no delta-8 rules averaged 1.36. That is an association. States differ in many ways, including cannabis laws and population, and the study design does not show that the bans caused the lower rates.

Could Congress change the dates again?

Yes. The December 11, 2026 date was set by a September 2026 appropriations law, and Congress can amend it. This article reflects the law as of October 26, 2026 and will be updated if the dates change.