Florida patients can carry up to 120 grams (4.2 ounces) unless the physician determines a patient needs more. Patients are allowed up to 36 grams (1.3 ounces) of THC (the active ingredient in marijuana) per month in extract forms. For the smokeable flower, patients may buy up to 2.5 oz per month. There is a 5 oz limit for the total amount of flowers you can have at any given time. Legal purchase amounts.