Foliar feeding can be very benefical to your plants during both the veg and flower stage. As far as all these products on the market which are miracle products to increase resin production or make your buds grow to the huge monsters the breeders and product manufacturers show you, mostly snake oil. Good overall health of your plant from beginning to end, the proper temps for your strain, with the correct amount and correct application times of nutes will do more than anything.
Molasses can help both as a foliar feed and added to the soil. If you are growing in soil molasses can help if your soil is amiss of the proper microbes. As a foliar feed molasses give you plant an extra boost of carbohydrates needed for rapid growth, too much can lead to, too much vegative growth with can lead to a weaker plant.
I hope this gives you some things to consider, here is a link on the use of molasses, whether it works or not only you can decide. When trying new things always try on one or two plants at a time so that you can see side by side with another plant if there is truly any difference.
Happy Growing