Paul,
I think we have a terminology disagreement. I don't think it's physiologically possible for laterals to have grapes. I think grape clusters are already formed in the bud before the bud even breaks. The vine doesn't just create them on the fly. I thinkl you may be talking about secondary and tertiary buds that would break from the area close to where the primary bud is. Those are not laterals. Laterals are formed from green tissue.IOW, the growing shoot. As far as environment is concerned, if you saw how dry a sandy soil can be no matter how much rain falls you would be amazed. Well drained soil doesn't hold any water therefore there is no moisture to create humidity from water held in a soil like clay.
Bob
.> > Mike,
Paul,