very critical... you started with way too big of a pot. You should never start them in 2 gal simply because the plant can not dry 2 gal of soil in a sufficient time before the roots start choking from lack of oxygen from being too wet. if you do start in 2 gallon pots, only water the actual root zone of the plant, and not the whole pot. That way the water is where the plant NEEDS IT. knowing your root zone is crucial. when i transplant i dont water in the entire container, just the area where the plants roots are and the entire top of the soil, because the rest is pointless to saturate when there are NO ROOTS in that ZONE. 1 gallon of container = 1 month of healthy growth. so when i transplant my plants to go into flower, i dont give them more room than they're going to use, or your wasting soil, water, nuts, and resources. for what its worth, my pots are never bigger than 5 gallons unless i veg a plant for longer than 3 months (< 3 month veg + 2 month flower = 5 gal container or less) I place clones into never bigger than 3/4 gal containers... then after 3 weeks when root ball has formed I transplant to typically 4 gallon containers, and flip within 3 weeks this allows the roots ROOM to grow in flower. waiting to flip after transplanting allows the plant time to acclimate to the new container and stabilize and the container is plenty of room to continue growing when they get to stretching in first 2 weeks of flower. If you do not transplant before flower and you have a rootbound container, it will be harder for the plant to grow to its genetic potential. The benefit to appropriately sized containers is that your root zone is the whole container when roots fill it in (usually by week 4 or 5 of flower), so you know where the roots need the water... also they suck the pots dry faster, which means more watering which DEFINITELY means more CEC (cation exchange capacity). CEC is CRITICAL to growth and development. when water molecules bond to soil particles stronger than the plant can pull them away for usage (hygroscopic soil), CEC comes to a dead halt, which means that your plants are no longer taking in any nutrients or water! you want your soil to approach being hygroscopic, but not to the point where CEC stops.
Just because they say you don't need to monitor Ph because of the soils "recipe" doesn't mean that you should ignore it all together. also, when you water you should get ~25% runoff (i.e. you put in 2 gals of water you want to see .5 gal drip out of the pot). you should be checking the ppm of that runoff and the ph. then you know if youre burning (too high of PPM coming out of the pot), or if your soil ph is off (which massively fucks available nutrients). Hope this helps you out a bit... Good Luck!