Nice poetic imagery.
I'm missing a chorus or an obvious recurring cadence, but neither is necessary, really...
Also, I am missing the point of the song, I think. Why isn't he returning to his farm/garden? Is he getting old, evidenced by the "hidden movement" and eyesight needing "improvement"? You could also be eluding to this with the "frayed" lettuce manes and thin "corn stalk legs" and celery "veins"...
Is he going crazy? He is seeing submarines (on a brown hill) and rockets, not to mention living vegetables and veggie animals... perhaps he's off to an institution?
My only suggestion would be to unify where the song is going, and that's really only my opinion. I would give the same suggestion to Led Zeppelin, but I think they did pretty well without my help.
