molasses is tricky and really should be used by ppl who have good experience. its good when U use it late into flowering (6 weeks or later) to add some flavor to the bud.
its not a super ingredient or anything, it just fills the buds with juices to help them swell, and slightly changes the flavor and aroma after curing.
but understand that it works best when ur plants are already on a very light feeding schedule, and u dont have much nutes to flush out.
Im at 6.5 weeks flowering now and the buds are done stretching. Ive been feeding 1/4 strength nutes once per week, and plain water in between feedings. but now im only feeding them 1 tablespoon of molasses per gallon and 2 pinches of a ripening formula, till harvest.
no need to flush it out bcuz its all organic. and its always better to use TOO LITTLE than to use TOO MUCH..