North American Fruit Explorers mailing list at ibiblio

["Lon J. Rombough" <lonrom@hevanet.com>]

That depends on the variety and the climate in which it grows.  Concord will usually produce a small tertiary crop, for example.  There isn't a huge amount of data on which grapes will produce tertiaries, unless the vines were tested by mechanically removing the primary and secondary shoots.  
Grapes in places where there is high light intensity usually have more fruitful buds than ones in shady areas.  Likewise, training systems that expose the developing buds to more light will increase the size and number of flower clusters that are produced.
-Lon Rombough
Grapes, writing, consulting, my book, The Grape Grower, at http://www.bunchgrapes.com  Winner of the Garden Writers Association "Best Talent in Writing" award for 2003. 
For even more grape lessons, go to  http://www.grapeschool.com
For all other things grape,   http://www.vitisearch.com

On Apr 17, 2008, at 8:32 PM, Donna &/or Kieran wrote:

Rob,   Depending on where you are, you may or may not actually get a crop. 
Someone who used to live up in NY explained to me that the reason 
Tennesseans get few grapes is the late frosts getting the primary and 
secondary buds, leaving only the tertiary buds to grow, which contain leaves 
but not flowers.    Donna