Wow. That's not what I thought I was seeing!Good question! The blue part is the original 2 gallon pot- I figured more room for roots would be a good thing, so I cut the bottom off of the original pot-, and sat it in a 5 gallon bucket full of dirt...plain old "yard dirt", so it weighed about a ton...but it worked pretty well...
Unfortunately, that plant was the weakest pot I've ever grown (Kerala Krush) it got me about as high as a CBD plant, but it was (allegedly) a THC plant.
Still, I'm glad I asked because that was very interesting what you did!