The short answer
There is no single US cannabis growing law. Cultivation is legal in some form in most states, but the details, plant counts, whether you need a medical card, whether home grow exists at all, come from your state legislature, not from Washington. Federally, cannabis is still a Schedule I controlled substance under the Controlled Substances Act. Hemp, defined as cannabis testing at 0.3% THC or less on a dry weight basis, was separated from that schedule by the 2018 Farm Bill and is regulated as an agricultural crop. So the plant on your windowsill has two possible legal identities, and which one applies depends on its THC content and where you live.
Two layers of law, and they do not agree
Federal law does not recognize state legalization for marijuana. That gap shows up in practical ways: banks are cautious, federally backed mortgages can be a problem, Section 8 housing rules still apply, and growing on federal land, including national parks and forests, is illegal even if you drove there from a legal state. State law is what protects you from state prosecution, and it is the only thing that does.
US State Cannabis Growing Laws: What You Can Legally Grow
Hemp and marijuana are the same species
Cannabis sativa covers both. The line is chemical, not botanical. Cross 0.3% THC and the crop is marijuana under federal law. Stay under it and you are in hemp territory, which is why CBD sold online is usually made from licensed hemp, not from someone's backyard medical plants. Hemp is a licensed agricultural crop in practice. State hemp programs require a license, reporting, sampling, and lab testing. No state hands out permits so a resident can grow a few hemp plants for homemade CBD oil.
cannabis growing laws by state
How state home grow rules usually work
The same handful of variables shows up in nearly every state statute:
state laws for cannabis home growing
- Plant counts. Some states count per adult, others cap the whole household. Oregon allows four plants per household. Colorado allows six per adult with a household max of twelve. Michigan caps at twelve per household.
- Mature vs. immature. Vermont permits two mature flowering plants and four immature ones. Maine allows three flowering plants and a much larger number of seedlings and immature plants.
- Location. Outdoor plants usually must be out of public view and behind a lock. Indoor grows are easier to keep compliant.
- Age and residency. Recreational grow is 21 and up. Medical grows may start at 18 in some states, and a few states require in-state residency.
- Sourcing. Seeds and clones generally cannot cross state lines legally, even between two legal states.
The four rough categories of states
- Recreational legal with home grow. Examples include Alaska, California, Colorado, Maine, Massachusetts, Michigan, Minnesota, Nevada, Ohio, Oregon, and Vermont. Minnesota allows up to eight plants per household, no more than four flowering.
- Recreational legal without home grow. Washington does not allow recreational home cultivation. Illinois and New Jersey legalized retail sales but kept home grow off the table for non-patients.
- Medical only, sometimes with a patient grow. Illinois allows registered patients a small number of plants. Florida allows medical cannabis but no home cultivation at all.
- No legal cultivation for any purpose. Idaho and Kansas sit here, along with a handful of other states where even medical programs are narrow or absent.
Categories shift almost every legislative session, so treat any list, including this one, as a starting point.
Where CBD fits into all of this
If your interest is CBD rather than high-THC flower, the rules you are looking for are hemp rules, and they are administered by state agriculture departments under USDA-approved plans. Licensed hemp farms are inspected, sampled, and tested. Finished CBD products from those farms are widely sold, though the FDA has not issued a general rule allowing CBD as a dietary supplement. Buying lab-tested CBD online is legal in all 50 states. Growing the hemp yourself is not, unless you hold a license.
A quick checklist before you plant anything
- Confirm your state's current plant limit and whether it is per person or per household.
- Check whether your state allows recreational grow, medical grow, or neither.
- Read your city and county rules too. Local bans and zoning limits are common.
- Check your lease, HOA, and any federal housing assistance.
- Keep plants locked, out of view, and away from anyone under 21.
- Do not carry plants, clones, or seeds across state lines.
Do plant counts include seedlings?
Sometimes. Several states count only flowering or mature plants, which is why clones and seedlings get their own line in the statute. Others count every rooted plant. This is the single most common way home growers accidentally break the law.
Can I grow CBD hemp at home?
Not legally in any state I have seen. Personal hemp cultivation falls outside licensed program rules.
Your state cannabis agency or department of agriculture publishes the current rules. That is the document to read, because it changes more often than anything written about it.