The Martha Stewart Show, Episode 5128
Begin by selecting two rocks that fit together nicely. (Gneiss, schist, limestone, or tufa are good options.) Apply less than a 1/4-inch of potter's clay to the inside of each rock.
Unpot plant and wash roots in water. Place roots over clay and sandwich between both rocks. Bring the two pieces together tightly, and place in trough filled halfway with scree. Add other plants as desired, washing roots in water.
Once the trough is planted, add scree mix around plants, taking special care to position the crown of the plants just above the scree. Fill trough to top. Water thoroughly and add a small amount of coarse sand. Close crevice with a little extra clay (even when the clay looks dry, it will hold moisture and nutrients for the plant). Use additional rocks and plants to finish planting trough.
Turface: a double-fired clay used on baseball diamonds, which provides excellent drainage and makes the soil mix lighter
Grit: a larger-sized sand, available in varieties from fine to medium to coarse
1/4-inch pea gravel: pebbles that are slightly larger in size than grit; can be found at local quarries
Greensand: mineral often used in organic gardening that acts as a slow-releasing source of nutrients
Potting soil (without perlite) or peat
Rock gardens are easy to build, and you can adapt them to small or large spaces using an innovative technique called crevice planting, which means placing a plant into a narrow space between two rocks. As an added bonus, since rock garden plants have evolved to survive in extreme conditions, they require very little care. Just water occasionally and you're all set.
Rock gardens can be planted in troughs using scree, a soil mix with high mineral content. Scree contains the following.