How to Buy Cannabis Flower Online: A Buying Guide

Start with state law

More than 20 states and the District of Columbia allow adult-use cannabis sales as of 2025. Other states allow medical use with a patient card. Federal law lists cannabis as a Schedule I controlled substance. No postal carrier or freight line may ship THC flower across state lines under federal law. A site that promises delivery to all 50 states is not a licensed dispensary.

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Age rules: 21 for adult use. Medical patients qualify at 18 or 21, set by state. Licensed sellers scan a government ID at checkout.

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Verify the license

Every legal dispensary holds a state license number. State cannabis regulators publish license lookup tools. Match the store name, address, and license number on the site against the state record. If the number is missing or does not match, stop.

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Read the label before you pay

• Total THC and total CBD, in percent or milligrams per gram.
• Terpene content, in percent or milligrams per gram.
• Harvest date and package date. Cannabinoids and terpenes break down over 6 to 12 months.
• Weight: 3.5 g (an eighth), 7 g, 14 g, or 28 g (an ounce).
• Batch or lot number.

NIDA reports that average THC in seized flower rose from about 4% in 1995 to about 15% in 2021. Labels on high-THC strains can read 25% to 35%. The NIDA figure covers confiscated samples, not retail shelf stock, so treat it as a trend line.

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Check the lab report

Most legal states require testing for potency, pesticides, mold, heavy metals, and residual solvents. Ask for the certificate of analysis (COA). The COA should name the cultivator, the batch, the lab, and the test date. A COA with no batch number proves nothing.

The FDA has not approved cannabis flower for any medical use. No cannabis product is FDA-approved for sale as a dietary supplement.

Payment and taxes

Card networks block marijuana transactions. Most dispensaries take cash or debit through a cashless ATM. Expect excise tax plus state and local sales tax. Combined rates run from about 10% to 37%, set by state.

Pitfalls

1. Credit card checkout and nationwide shipping claims.
2. No license number, or a number that fails the state lookup.
3. No COA, or a COA with no batch identifier.
4. Prices far below the state median. Low price often means old flower, mold, or seeded buds.
5. Gift offers and free flower attached to another purchase.
6. THCa hemp flower sold under the 2018 Farm Bill. Hemp must test at or below 0.3% delta-9 THC on a dry weight basis. THCa converts to THC when heated. State rules on THCa flower differ, and several states have banned it.
7. No return policy. Flower is not returnable in most states after it leaves the counter.