Growing in tubes seemed like the best way to pot a lot of plants, cheaply & cleanly. My first one of these was 10 feet of wheat grass. ( On the right )
But only last fall, when I planted a salad mix in 4 different smaller test tubes, did the following occur to me .........
A very simple machine, that grows salad greens, and herbs for 2 - 4 people. Less than 6 feet long, fits on a small apt. balcony .
The only moving part is a ball valve.