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St. Louis County, MO Cannabis Regulations: Personal Cultivation Limits (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Governing law
Mo. Const. art. XIV, §2.4(24)
Minimum age
21 years old
Per-person plant limit
6 flowering, 6 nonflowering, 6 clones
Per-residence cap
12 flowering plants max
Registration fee
$100 per year, renewable annually
Storage rule
Locked, not visible from public place
Violation penalty
Up to $250 civil fine plus forfeiture

Summary

Missouri's Constitution lets any adult twenty-one or older register with the Department of Health and Senior Services to grow marijuana at home, including in unincorporated St. Louis County. A registration card permits up to six flowering plants, six nonflowering plants over fourteen inches, and six clones, but no more than twelve flowering plants total at one residence, and every plant must stay locked up and hidden from public view.

These county ordinances apply to unincorporated areas of St. Louis County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

(24) Except for good cause, a person at least twenty-one years of age may obtain a registration card from the department to cultivate up to six flowering marijuana plants, six nonflowering marijuana plants (over fourteen inches tall), and six clones (plants under fourteen inches tall) for non-commercial use, provided: (a) The plants and any marijuana produced by the plants in excess of three ounces are kept at one private residence, are in a locked space, and are not visible by normal, unaided vision from a public place; and (b) Not more than twelve flowering marijuana plants are kept in or on the grounds of a private residence at one time. The card shall be valid for twelve months from its date of issuance and shall be renewable. The department shall charge an annual fee for the card of one hundred dollars, with such rate to be increased or decreased each year by the percentage of increase or decrease from the end of the previous calendar year of the Consumer Price Index, or successor index as published by the U.S. Department of Labor, or its successor agency.

View official code

Official source re-checked September 7, 2026: the cited page had not changed since it was quoted.

Full Breakdown

Missouri Constitution Article XIV, Section 2, adopted by voters as Amendment 3 in November 2022 and effective December 8, 2022, sets the only home-grow limits that reach unincorporated St. Louis County; the county's own zoning and health code does not layer on a separate cultivation cap. " The card authorizes up to six flowering plants, six nonflowering plants (over fourteen inches tall), and six clones (under fourteen inches) for non-commercial use. The hard residence cap is separate from the per-person allowance: no more than twelve flowering plants total may sit in or on the grounds of one private residence at a time, no matter how many registered adults live there.

Every plant, and any harvested marijuana above three ounces, must stay inside the residence in a locked space and out of normal, unaided view from a public place. Registration cards run twelve months and renew annually for a department fee of one hundred dollars, adjusted yearly for the Consumer Price Index. Separately, subsection 10(1)(b) decriminalizes possessing, planting, cultivating, harvesting, drying, processing or manufacturing marijuana plants within these same limits for a registered adult, so a compliant home grow cannot be the basis of a state or local criminal charge, civil fine, search, or asset seizure.

Local Control under subsection 5 lets a municipality or county ban commercial dispensary and microbusiness facilities by ballot vote, but that local-control power does not extend to banning or shrinking the personal cultivation allowance itself, which is fixed by the constitutional text statewide.

Violations & Fines

Growing plants visible to the naked eye from a public place carries a civil penalty up to two hundred fifty dollars plus forfeiture of the marijuana, and keeping plants outside a locked space draws the same civil penalty and forfeiture. Cultivating more than twice the registered limit escalates from a civil infraction (up to two hundred fifty dollars, then five hundred dollars) to a misdemeanor with a fine up to one thousand dollars on a third violation, with community service allowed in lieu of payment.

Frequently Asked Questions

Do I need a state registration card to grow marijuana at home in St. Louis County?
Yes. Article XIV, Section 2.4(24) requires an adult twenty-one or older to hold a personal cultivation registration card from the Missouri Department of Health and Senior Services before growing at a private residence in unincorporated St. Louis County; the card costs one hundred dollars a year and is renewable.
How many marijuana plants can one household have?
Up to six flowering plants, six nonflowering plants over fourteen inches, and six clones under fourteen inches per registered adult, but never more than twelve flowering plants total on the grounds of one private residence at a time, regardless of how many registered adults live there.
Can St. Louis County ban home marijuana cultivation?
No. The Local Control provision in subsection 5 only lets a local government put a ban on commercial dispensary or microbusiness facilities to a ballot vote; it does not authorize banning or reducing the personal cultivation allowance the constitution sets statewide.
What happens if my plants are visible from the street?
Subsection 10(2) makes that a civil penalty of up to two hundred fifty dollars plus forfeiture of the marijuana, the same penalty that applies if the plants are not kept in a locked space under subsection 10(3). Both penalties can stack if a grower violates both rules on the same property.

Sources & Official References

Other rules in St. Louis County

All St. Louis County rules

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