Yes, veggies--especially dark green ones--can turn stools colors. Also, poops that are not put together very well get kind of weird. When I'm normal, my poop looks normal. When my guts are acting up, my poop is more likely to turn colors based on what I eat, and I start seeing bits and pieces of undigested food in it as well. I think you have all of this stuff in normal poop, but you just don't see it because it's all compacted like it's supposed to be. When it starts getting loose, all of those food pieces and colors become visible.
Poop can have a range of brown colors. Gosh, mine cna be anywhere from yellow to rather dark brown. It's black that you have to watch out for. Black can indicate blood (unless you took some Pepto Bismol--the bi****h in it turns your stools black).