It's on the rim of my CD too.
I think I've cottoned on to something I don't think anyone else in this thread has mentioned - it seems obvious to me now, though.
Because of:
The blatant apocalyptic themes.
The references to nature - to seeds - to AG(riculture).
I think that:
It's not "I overflow, man", it's "I overflow man" - as in, "I overflow with man".
It's a message, yes, but it's not from a stoner, or from a disgruntled graphic artist, or from someone with incontinence.
It's from the Earth.
The rapid population growth of the human race is becoming more and more dire every day - hence, the Earth, overflowing with man.
And moreover, what better solution is there to these sick times than our collapse?