Southwestern Idaho classifies as a semi-arid steppe climate, receiving only 10 to 12 inches of annual precipitation. Because traditional turf-centric irrigation systems are designed for shallow, frequent watering, they often fail to meet the biological needs of deep-rooted trees in areas like Eagle and Caldwell. Trees rely on a balance of oxygen and water in the soil pore spaces. The heavy clay soils common along the Boise River corridor drain very slowly. Frequent, shallow watering keeps the upper layer of soil saturated—choking off oxygen and promoting shallow, weak root systems—while leaving the deeper root zones bone dry. Proper arboricultural watering requires infrequent but deep irrigation. Applying water slowly allows it to percolate 12 to 18 inches down into the soil profile. This encourages roots to grow downward, increasing the tree’s structural stability and its resilience against the intense heat of an Idaho summer. Always check the soil moisture at a depth of 6 inches before watering; if it is moist, wait.