[quote='George[_10_];866622']On Tue, 6 Oct 2009 17:21:20 -0600, "Suzanne D."
wrote:

,,.

I am wondering if there would be any value to starting 1/2 or even 1/3 of my
seeds in the spring, and starting more a month or two later, so that I could
plant some young plants very early, plant some a bit later, and then plant
some in mid-summer. ...

(Central NYS, zone 5+) I've done this with other things, not tomatoes.
(Tomatoes are just a race against time here.) I can't say I understand
our results completely, but it seems like there's a 'sweet spot', sort
of late June to mid-July. Things planted later, even at the end of
July, even well within their time-to-harvest, just don't seem to thrive.
I suspect it has to do with the amount and angle of the sun. It may be
a local thing - August and September can be kind of cloudy here.

G[/QUOT

you didnot mention what kinds of tomatoes you are planting . l would not worry about the flowering some types of tomatoes do that.