I currently grow in coco/perlite, so ph is more important than in soil, but honestly I don't correct my ph even in coco these days, simply because I use RO water and know that my nute mix comes out to an acceptable ph range. I do test my res every now and again, just to make sure I'm on target, but I'm certainly not religious about it. I don't even use ph up or down TBH. I simply balance my ph with complimentary levels of Si and acidic organic based nutes.
That said, I did grow in soil for a long time before coco, and I for a long time just used tap water. One year I moved to a new place, and was growing in organic soil with non-ph'd tap water, My grow suddenly suffered, and I didn't initially understand why. I talked to my grow buddy about it, who grew hydro at the time, and he asked me what my ph was, and of course I told him that I grew in soil, so my water ph didn't matter. We debated it for a while, and a week later I decided that I might as well get some ph strips and test my water. Well, I came to find out that the water was ph 8.5. Wondering if my buddy was right, I got some ph down, and corrected my water to 6.5 for the next week or two, and the growth difference was night and day. This is my real world experience, take it or leave it.
