How do I prevent Excel from plotting a cell w/ a formula as a "ze.
 

I am setting up a trend chart for 2005 and want to setup the chart now so
that it updates each week as data is added. The problem I am having is that
the chart is plotting all future "result" cells as "zeros" because of the
formula in each cell. I am blanking out all future "result" column cells w/
(IF) logic statements w/ the (ISBLANK) function so nothing appears in the
cell until the right date, but its still being plotted as a zero. Is there a
way to prevent Excel from plotting these "formula only" cells as "zeros"?