newb question

the summer solstice is what throws outdoor plants into flower, right?

I don't believe so... although I don't grow outdoor I know that plants flower during the winter (this is emulated indoors with a 12on/12off light schedule). Typically if a plant is getting 16+ hours of sunlight it will be in a vegetative state. http://en.wikipedia.org/wiki/Summer_solstice that is a link to what the Summer Soltice actually is, no idea what that would have to do with throwing a plant into flower.

the angle of the sun, in the sky, also.

the summer solstice is June 21 which is the first official day of summer which has nothing to do with the flowering cycle. outdoors, plants go into flower when the days start getting shorter, it realizes winter is coming so it starts trying to reproduce. the winter solistice is december 21

Yepp.. Now time to blaze up!

It's the equinox (autumnal) - when night and day is roughly the same in length. That's when you get the 12'ish hours of darkness that induce flowering.