In this video, Ask This Old House landscape contractor Roger Cook creates a water-efficient waffle garden.
1. Use a square-blade shovel to mark a series of square cells on the ground. Make each cell the width of two shovel blades. Space the individual cells about 12 inches apart.
2. Pile up clay-rich soil around each cell, creating a raised berm. Firmly compact the berms by pounding them flat with the shovel and then walking across them.
3. Use a pickax to break up and loosen the soil within each square cell.
4. Add coarse sand and compost to the loosened soil; mix well.
5. Plant a variety of vegetable seeds within each cell to a depth that's 1½ times the diameter of each seed.
6. Cover the seeds with the amended soil, then lightly water the entire waffle garden, making sure to soak each cell.