By Gary Thomas
At the Lowell School in Washington, DC, a gravel garden was used to teach school children how to grow food without using any fertilizer or soil. It taught the students about sustainability and nutrition.

The Lowell School gravel garden in Washington, DC growing various types of lettuce, along with corn, cucumbers and marigolds. (PRNewsFoto/To Soil Less)
The gravel garden was donated by To Soil Less, a company that shares methods for gravel gardening with persons and communities having interest in sustainable gardening. The donation was part of the To Soil Less Gravel School program. The program endeavors to address problems regarding obesity and K-12 nutrition by taking gravel gardening to educational institutions. It also helps students to experiment and study about gravel gardening.
In mid-March, lettuce was planted in the Lowell School gravel garden. Within four months, the pre-primary students in the school harvested the lettuce five times. The school playground and the garden are situated adjacent to each other, which allow the students to watch the growth of the plants. Apart from lettuce, other plans including cucumbers, corn and marigolds were grown. The students were able to study interactively about nutrition and sustainable gardening when they were playing.
Lowell school teachers have converted gravel gardening into gravel science in the classroom. Students were shown how plants could sustainably grow without soil. Stefania Rubino, the Pre-Primary School director, stated that children took care of the garden, drew pictures, measured the growth of the plants, predicted further growth and made observations. They also harvested and ate the lettuce, she said.
Source : http://www.tosoilless.com