that is neat you can see the bottom node on the upside down plant has undergone more growth than the bottom node on the other one. It looks like they have about the same amount of leaves, but the topsy turvy plant is growing larger and faster.
Excellent deduction, Watson. Maybe I can shed a bit of light on this one...
Judging from the pictures, all his plants are fresh from seed. And when plants are from seed, they have a tendency to grow more uniform and less bushy. Because of this, the natural canopy of the leaves blocks the lower nodes from getting sufficient light, thereby reducing their growth rate. However, the topsy turvy plant is getting light from a slightly different angle, allowing for the rays to penetrate the lower nodes.
It's like a batch of seedlings I had not to long ago.... Out of 8 seeds, I topped two of them and a very young age. The non-topped 6 went on to grow around 12 inches tall, with the lower nodes growing maybe an inch or two. The lower node growth of the two topped ones, however, was almost equivalent to the height of the plant. This happened because when I topped them, the canopy grew differently, allowing for the light to penetrate further down.
All and all, I'm diggin' this topsy turvy experiment.
-AR