I wound up with the plastic on the inside as you do.
The plastic does not look any better.
I placed a small deep saucer inside the plastic, and filled it with vermiculite.
Filled to top with potting soil, and then planted with the old "vining" petunias.
Then I lift them into position before watering them.
I did two others with petunia integrifolia, but they were too heavy to hang so
they are on a table for now.
