The molasses can be used in hydro just not aero grows. When I use it and have used it over the years the mixture is 2 tablespoons of black strap moilasses per gallon of water. Do this once each res change or once a week basically as you should be changing your res at least once a week. I disolve it in a gallon of warm water and stir til it is disolved and the water is an even brown then add it to the res and mix again. Use blackstrap molasses such as Grandmas shown in the thread as it has no sulpher. Do not add plain sugar or brown sugar to your res it is not good. In soil I would give molasses no more then possibly twice a week as it will make an nvite to insects and can cause mold growth on your soil medium since your not chnaging the soil during the grow. The burst of carbohydrates helps the plants use thier nutrients better and promotes faster cell division and resin producrion ie thicker plants, heavier buds and more crystals. You can by refined products that are made from molasses for hydro such as Sweet, Sugar daddy, Sweet Leaf and carbo load all do about the same. To add wiegfht and heavy crystals and harden flowers good additives are like Humboldt County's gravity and fox farm bestie Bloomz and Cha-Ching
i was considering Gravity but it is sooo easy to screw up with it.
it can cause big issues if you over use it. they even warn you on the bottle less is better and it is expensive as all hell
molasses has just about no down side. i break a bottle in half and shake it with water and then add it to my watering.
i also have my feeder tubes just below soil surface so my soil always looks dry on top.
if you dig in 1/2 inch after water you hit moisture.
keeps the buggies down
also molasses makes the buds sticky and sweet.