How to Figure the Number of Stones for a Garden Border

Measure the length of the garden bed border you wish to line with stone. A retractable or bending tape measure works best, especially if the border is curved or wavy. Alternatively, lay out garden hose to precisely line the curvilinear border edge, mark the border's end on the hose and then straighten the hose and measure it with a tape measure.

Decide what size of stone you want to line the border. Fewer larger rocks laid end to end are required to cover the same distance as smaller rocks. Use sample rocks or other variously sized items to place in your garden to help you determine what size you find most attractive.

Measure the size you want to make the garden border. Just a rough diameter is needed. Use the tape measure to approximate the diameter of the rock. For example, stones between 10 and 15 inches in diameter is easier to acquire than rocks that must be precisely 12 inches.

Divide the desired stone diameter into the full border length. This yields an approximate number of rocks needed to create the rock border. For example, you want rocks that are 10 inches in diameter and the border length is 20 feet. Twenty feet equals 240 inches. That means you'll need a minimum of 24 stones, each about 10 inches wide to create the rock border.

Take your calculations into the field to pick up rocks on your property to cover the appropriate length or to the landscape supply company selling rock. Look for stones that, on average, are the rough diameter size you desire. Add 10 percent more in quantity since it's always better to have more than not enough to complete the project.