The Farm Bill, or Agriculture Improvement Act of 2018, legalized hemp. Here’s the relevant passage:
SEC. 297A. DEFINITIONS.
(1) HEMP.—The term ‘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 delta9 tetrahydrocannabinol concentration of not more than 0.3 percent on a dry weight basis.
SEC. 12619. CONFORMING CHANGES TO CONTROLLED SUBSTANCES ACT.
(a) IN GENERAL.—Section 102(16) of the Controlled Substances Act (21 U.S.C. 802(16)) is amended—
(1) by striking ‘‘(16) The’’ and inserting ‘‘(16)(A) Subject to subparagraph (B), the’’; and
(2) by striking ‘‘Such term does not include the’’ and inserting the following:
‘‘(B) The term ‘marihuana does not include—
‘‘(i) hemp, as defined in section 297A of the Agricultural Marketing Act of 1946; or
‘‘(ii) the’’. (b) TETRAHYDROCANNABINOL.—Schedule I, as set forth in section 202(c) of the Controlled Substances Act (21 U.S.C. 812(c)), is amended in subsection
(c)(17) by inserting after ‘‘Tetrahydrocannabinols’’ the following: ‘‘, except for tetrahydrocannabinols in hemp (as defined under section 297A of the Agricultural Marketing Act of 1946)’’.