Edward,
I have to find a good "balance" in the Guide to not make it too complicated - yet be effective. The "simple" approach is as I have in the Guide to cut the fabric just large enough to cover the base area. This will inhibit most of the roots from going down in to the reservoir. If you *really* want to minimize them, run the fabric up the side walls a bit.
But then this necessitates cutting a slit in the fabric pieces for the filler tube (another complication and step). So you see my dilemma in trying to keep the Guide simple, yet have it effective for 95% of the Builders.
Raybo
