Longmont, CO Cannabis Regulations: Home Cultivation (2026)

Personal-use marijuana home grow in Longmont is regulated under LMC Chapter 9.60 (Medical and Retail Marijuana) — specifically § 9.60.060, which imposes the city's per-dwelling-unit ceiling of 30 plants. Within that ceiling, state law sets the per-person rule: Colorado Constitution Article XVIII, Section 16 (Amendment 64) and C.R.S. 18-18-406(3)(a) allow an adult 21 or older to grow up to six marijuana plants, with no more than three flowering at any time. C.R.S. 18-18-406.3 (HB 17-1220) caps a residential property's household total at 12 plants regardless of how many adults live there, unless the home is licensed as a medical caregiver residence under state rules. Plants must be grown in an enclosed and locked space and may not be visible from a public place. Cultivation is allowed in the primary residence, in an accessory structure (with the same enclosed-and-locked requirement), and — with both owner and resident permission — in common areas of multifamily or attached residential buildings. Outdoor home cultivation is permitted only inside an enclosed and locked space. Renters need landlord permission and remain subject to lease terms. Longmont separately prohibits commercial cultivation, production, and testing of both medical and recreational marijuana; the only commercial cannabis activity allowed inside city limits is licensed retail sale (capped at four stores) and, since January 28, 2025, licensed marijuana hospitality. Sale or distribution of home-grown marijuana is a state and local offense.