Cannabis plant growing limits: the short answer

No federal law sets a plant count for home growing. Congress sets one number for hemp: 0.3% THC. Plant counts come from state law. Counts run from 4 plants per household in Oregon to 12 plants in Michigan. Some states ban home grow.

Federal rules

Hemp

Hemp is Cannabis sativa L. with a delta-9 THC concentration at or below 0.3% on a dry weight basis (7 U.S.C. 1639o). A grower needs a USDA license or a license under a state or tribal plan approved by USDA. Federal rules set no plant cap. Limits are land area, sampling, and testing.

  • Sampling within 30 days before harvest.
  • Testing at a DEA-registered lab.
  • A result above 0.3% and at or below 0.5% counts as a negligent violation.
  • A result above 0.5% is a violation. The crop goes to disposal.
  • Acreage must be reported to the USDA Farm Service Agency.

Marijuana

Cannabis above 0.3% THC is marijuana under federal law and sits in Schedule I (21 U.S.C. 812). Federal law sets no plant count for marijuana. It sets criminal penalties. A state license does not change federal status.

State plant counts, adult use

  • California: 6 plants per private residence. Six is the cap no matter how many adults live there (Business and Professions Code 11362.2).
  • Colorado: 6 plants per adult 21 and older. Household cap is 12.
  • Oregon: 4 plants per residence.
  • Michigan: 12 plants at a residence.
  • New York: 6 plants per adult, 12 per household.
  • Ohio: 6 plants per adult, 12 per household.
  • Washington: home grow is not allowed for adult use under state law.

Medical plant counts

  • Colorado: 12 plants per patient. A doctor can authorize a higher plant count.
  • Oregon: 6 mature and 12 immature plants per patient registered with the Oregon Medical Marijuana Program.
  • Michigan: 12 plants per patient. A caregiver can grow for up to 5 patients.
  • Illinois: 5 plants per patient in the medical program.

Mature plants vs immature plants

States count plants by stage. Oregon lists mature flowering plants and immature plants as two numbers. A clone or a seedling counts as immature in several states. A plant in flower counts as mature. Read the state statute, because the definitions differ.

Cultivation licenses

Commercial licenses use canopy area in place of plant count in several states. California issues cultivator licenses in canopy tiers measured in square feet. Licensed grows report plant and harvest data to a track-and-trace system.

What voids a plant limit

  • Growing without a state license or a medical registration.
  • Selling flower grown at home.
  • Plants visible from a public place.
  • Moving plants or product across state lines.
  • City or county bans that are stricter than state law.

Check your state in 3 steps

  1. Find the state cannabis regulator, such as the California Department of Cannabis Control, Colorado Marijuana Enforcement Division, or Oregon Liquor and Cannabis Commission.
  2. Read the statute section on home cultivation.
  3. Check city and county code for a lower cap or a ban.

Counts change. State legislatures amend plant limits between sessions. Verify the current text before you plant. A hemp grow carries a THC test risk that a plant count does not cover: one failed test can void the crop.