Patty,
For the plant stands, since open top barrels are what is needed, I just go to Trinsic barrier island and nab gypsy/brigand barrels there (always several camps spawning at any given time and your intrepid crafter can get the brigands guardwhacked

) but you need close to GM lockpicking to do that from what I recall.
Also, by way of possible safety tip, there used to be a weird bug that sometimes made the barrels despawn with the camp even though they were in your pack, so I generally gate to a different subserver and drop off the barrels after I get them. Not sure if the bug is still around, I just do that out of habit to make sure.
-Skylark