The fabric bags are nice, but difficult to transplant from. So not uncommon for growers to go into big fabric (as opposed to going from a couple smaller pots). But this makes watering much harder to regulate. With your size plants, they’d normally be in a 1 gallon (nursery, which is really .7 gallon) and wouldn't come close to using 1.5 gallons of water. You'll need to run a fine line between giving a good soaking and watering too often. I'd only water out a little past your drip line at this point and not soak the entire pot (which in your case might take a week or so to dry out).
edit:most certainly take Aqua Man's advice on not doing a lot of small waterings, however.