yellowing leaves during veg, what to do?

here are some pictures of my plant, its about 2 1/2 months old and the leaves are starting to turn yellow and i havent even started flowering yet. i know that the leaves with only three point will fall off soon which i think is normal. but im more concerned with the five pointed one which is only starting to yellow at the tip. when i noticed all this, i switched to a larger pot and watered (which i intended to do today anyway). when i switched i noticed the whole chunk of soil and root was pretty dry, could this problem stem from underwatering. just let me know what you think is the cause. any advise is much appreciated.