Quote Originally Posted by khronik
The one nice thing about using huge pots is that it can mitigate stress on the plant, especially heat stress. If your grow area is already stress-free, and you water your plants enough, you probably won't notice the benefits as much.
Exactly.
Bigger yield is not the only reason to use bigger pots.
More soil allows more chelation of minerals, which creates a natural buffer for the fertilizers, so you are less likely to get nutrient burn. And you get more room for root growth, which means more steady and even nutrient absorbtion.
A plant in a 15 gallon pot will uptake the same amount of nutrients as one in a 7 gallon pot, but it takes it more evenly and naturally in the #15. The #15 should have less fluctuation in nutrient levels, meaning less stress on the plant.
Plus the extra room for root growth adds stability.