I have failed on several occasions to grow spinach in my 2 ft by 4 ft hydroponic shelf gardens. The big problem was getting the seeds to germinate. Then I came across a KZread video showing a simple way to do that. Now I have the first test crop growing. There are still some things to do that should improve production. This video also shows how these two simple shelf gardens provide lettuce the year around by having one crop coming on as another is near its end cycle.