Hi. I'm new here and to gardening, so any advice is appreciated, but I have one question most specifically.
I live on a West-facing hill in SW PA. I just converted an old woodpile/trash heap into a garden bed (great dark soil underneath!!) and the way I did it was by terracing with concrete test cylinders and sections of terra cotta sewage pipe (both free on craigslist!!). I've got all sorts of ideas of things I'd like to plant in the beds proper (although thoughts appreciated) but what I'm stuck on is the terra cotta pipes. They're filled with good soil and so I'd like to plant something in them, but I'm not sure what would thrive in the small diameters. The purple pipes are about 8" inside, and the red ones are about 4.5". The pipes are 10-12" deep, and connect underneath to soil, so I think water should be able to drain out ok.
Other information:
-The site as near as I can tell gets dappled sunlight 10-2, full sun from then on.
-There are 15 big purple pipes, and around 30 skinny red ones. The beds are terraced and approximately 16'x4.5' (lower) and 16'x3' (upper)
I am most interested in producing produce, although flower suggestions are welcome too.

Picture of the garden: