In my previous position as Assistant Food Service Director for Hingham Public Schools, I had the wonderful opportunity to lead the Hingham High School Farm to School team. One of my responsibilities in that role was to grow lettuce for the high school cafeteria lunches!
At the high school, we grew lettuce with the EvanLEE Organics' Grow Towers, which are indoor growing racks. We had grow towers in the cafeteria kitchen, classrooms, and even the high school greenhouse.
The grow towers use a terraponic system. In this system, plant trays are planted with soil and seeds as usual, but instead of watering the soil directly, water is added to the water pan that the trays rest in. Holes in the bottom of the planted trays allow the soil and plants to take up water as needed.