pH levels in desert soils are very different than other parts of the country. pH is measured on a scale from 0 to 14, with 7 being a neutral measurement. Acidic soils are on the lower end of the scale, while alkaline soils - which we have in the desert Southwest - are on the higher end of the scale. Acidic soils are generally found in parts of the country with high humidity and abundant rainfall.
A high pH is one with a reading over 7.8. Many soils with a reading this high have high contents of salt in them and require different watering practices to allow the roots of plants, trees and turf to take water from the soil. Deep and infrequent watering help to flush salts past the root zones of the plant species and will react favorably.
Look for burning on the tips of plants as an indication of salt burn. Increase watering to the plant to alleviate salt burn. Micro-nutrients, such as iron, manganese and zinc, are generally unavailable in alkaline soils and will result in various stages of chlorosis or yellowing of the leaves in many plants. Queen palms are an example of a sensitive plant requiring more care than normal.
You can lower your pH by applying sulfur and watering more deeply.
Understanding pH and soils will help you manage your landscapes.