Marathon II is not labeled for marijuana use. We recommend reaching out to your local Dept of AG for a list of approved products.
Marathon II Insecticide is mixed at 0.45 to 0.6 fl. oz. per 1000 sq ft which is usually to a gallon of water. Please refer to the product label for complete instructions.
Per the product label, Marathon II can be used in greenhouses but does not specifically list basil.