You should prepare your soil in advance so you don't have to deal with ph issues. It's not hydroponics, where the plants respond immediately to changes in the water. Plants grown in soil can take a few days to a week to respond to changes in your routine.
The easiest and most common method of stabilizing the ph of your soil is to mix in dolomite lime ($3.50, home depot) 1 cup per cubic ft or 2 TBSP per gallon of soil. I've got a plant 5-6 months old, checked the ph for the first time in a month, still 6.5