President José Mujica and his cabinet signed long-awaited rules for Uruguay’s legal marijuana marketplace on Tuesday. Uruguayan citizens and legal residents 18 or older may now register for licenses to cultivate up to six marijuana plants per household and harvest 480 grams a year, or join a marijuana growing club with 15 to 45 members and no more than 99 plants. Pharmacies are expected to stock government-approved marijuana cigarettes for sale by year’s end. Licensed buyers will be able to purchase up to 10 grams a week or 40 grams a month, at a cost starting at about 90 cents a gram, to be adjusted to compete with illegal marijuana.