watering root line in soil

hi all, first post and question here, i hope i can get a good answer from the experts... i have always grown in a soil medium.. ive been told that my plants like to have dry feet and i should always water the root line of the plant.. the area where the rain would naturally run off the leaves.. this has always worked great for me in the past... the roots seem to find the water i put down for them... my question is im doing some lst-ing now and my foliage is all over the place.. will the roots follow the canopy or is the plant genetically predisposed to a certain root zone or root line? im sure i'll get the right answer here.. i dont post much but im here often looking for ongoing questions that arise in my crops...

roots look for moisture and nutes, just water normally, then allow the soil to get a bit dry before you water again. they don't like to be wet all the time, and the plant will tell you by drooping if you are letting it get too dry for too long....

By letting it dry between waterings, you will make the roots grow and 'search' for water and nutes, therefore building up the rootball.