how many plants

[dj'slawnservice]

how many plants needed

I've got a total of 659 sq. ft. to plant, the flowers are to be spaced 9" to 12" apart......if I do it on the 12" spacing will I need 659 plants? Cause I'm thinking ....don't plant at the edge of the beds, to allow room for plant spread?
How to figure this? Is there a formula?
Thanks.

[diginahole]

there is a formula, I just posted it the other day. Click here (http://www.lawnsite.com/showthread.php?threadid=27731) to see the thread.