With some plants on there to see of it works, and it does.

Looking really good there. I like it. I would just be worried without a middle stringer in each row in fear of a pail falling if not set properly on the two that are there.

It wont fall over. I put the bars closer together so that the buckets fit right in. No bouncing or moving. Now if there is an earthquake, buckets falling over would be the last thing to I would worry about (Im in CA).

If you wanted security for the top row, you could add 2 columns at the sides and Tye some rope around the top row of buckets to hold them in place. You could even do it for the second row. They wont move after that. You probably could also use those columns as holders for a tarp/cover if it gets cold.

I didn't think about that but it would be easy to do.