I mix my ferts one gallon at a time but only use a third of it per watering. I am now mixing my bloom ferts using 1/4 tsp. Bloom Booster MG per gallon of water......this is ph corrected water and I also add 1Tblsp. of molasses. A few days later I'm getting about an inch of foam on top of the water level in the jug......is this fermenting? Can this harm the plants? Do I need to add the molasses just before I water to make sure I'm not feeding the plants alcohol?
The molasses feeds(sugars) any microbes in your mix, thus the foam action . I wouldnt let it sit around too long without some aeration. Only mix what your gonna use up is my advice. It could spoil on you without water movement. jmo