i do believe that 3 weeks is 21 days, since a full week is 7 days. me my-self i dont consider it being a plant @ all until it has sprouted from its seed casing. So is what i am saying is that i start my plants life the day that it was brought into this world. Lets say for instance that you have a child right, while the baby is in the mothers womb its not considered to be 1,2,3,4, etc days old, until being born then the counter begins. Your BIRTHDAY didn't start when you were a sperm cell or egg,or growing inside the surrogate, it started the day that you were born! I hope this helps you.
As for the molasses, sure i use it here and there; mostly just during the last 6 weeks of the flowering phase, pretty much to add carbs so that it make my plants calyxs swell up and put on weight. Remember this and remember this always; to much sugar can and usually will turn in to ALCOHOL. With thus being said, alcohol has antiseptic properties; which can/will KILL off microbial organisms, meaning that it can/will fuck up your roots Rhizosphere. So use Molasses respectively my good friend.
Happy Farming! :dance: