molasses is not for the plant, but the bacterial complex living on the roots of your plant.
bacteria provide minerals not easily dissolved in water in an accessible form for your plants, in exchange your plants give the bacteria some sugar they need for energy.
this is a very fine line to walk, too little and their will be no noticeable effect, too much and the bacteria will stop looking to your plants for sugar and instead exclusively look for the ''free sugar' you provided in the molasses. effectively cutting off the supply of certain nutrients to your plant.
if you are new to growing plants, generally speaking, i would leave the molasses alone.