Alandscaper wants to plant shrubs that require a soil ph of 7.0 near some evergreen trees. which ph would indicate that the soil has ten times the h+ concentration he desires, so he should add an alkaline material to the soil?

The correct answer is pH 6.0.  

In the given case, as the landscaper wants to plant shrubs that need a soil pH of 7.0, thus, if the pH of the soil is 6.0, then he would need to add some alkaline components to the soil.  

The pH measures the accessible concentration of hydrogen ions in a solution and illustrates the comparative level of alkalinity or acidity measured on the scale of 1 to 14. The pH is logarithmic, with 14 gradations. Each elevation of 1.0 pH signifies a difference of ten times either more acidic or basic. For example, pH 6 is 10 times more acidic in comparison to pH 7.0.