i take that approach that if i am watering then it is the same stuff- rain water, one cap of my plant probiotic (basically quantum total and the one before that in a fermenter that i add molassass and water to yearly) one cap of kelpmax, one scoop of rays fert pellets.
in a 2 gallon sprayer. i spray about 1/4 of my plants each time i fill it and so each plant gets it once or twice a month