Can I use 1 in pvc
 

Whats up Ron?

Hey buddy, in the 9 plant garden it says to use 1/2 in PVC. Can I use 1 in pvc instead like the 11 plant garden. Also im spacing the bottles 10" apart from each other. How tall will my tomatoe plants get in the 2 liter bottle 16oz solo cups? Will the roots be ok?

The 9 plant plans are old plans. When I built my first 2-liter garden I used 3/4 inch PVC. Then I used 1/2 inch for a few years. Now I use 1 inch PVC because the bottles are removable and I don't have to grind, drill or glue the hell out of the bottles to stop the leaks.
IT DOESN'T MATTER if you build a 2 plant garden, a 11 plant garden, or a 500 plant garden they all work the same. The only difference is how you arrange the bottles.
Yes a 16 oz solo cup can grow a 3 or 4 ft. plant.