Gutter Garden
We tried an experiment this year and put up a piece of plastic guttering to use as a small vegetable garden. It’s not worked out too badly. The lettuce is growing the best with the spring onions and radishes not doing as well. It’s still very handy to have veggies to pick just outside the kitchen.

More of a close up.

I don’t remember where I first saw this mentioned but this is the most likely.