When I went to the National Ag conference a few weeks ago, I went to a session that was container gardening. I found that this may the best option for me. Since I work with students that have disabilities, I can use container gardening to differentiate instruction.
To the left is a picture of a gutter. The students would glue on the sides and then add dirt and seeds. They did mention that the best plants for this container would be leafy veggies such as lettuces or greens. Also, they said that with this that you could cut off the top and the plant could keep producing more. I will be using this in my garden this year.