Soil analysis

A thorough analysis of both the physical and chemical characteristics of the soil is important when developing a water-wise landscape. Since plants with deep roots continue to have access to moisture after surface soil begins to dry out, a primary goal of Xeriscape is to encourage plants to develop deep root systems. In urban areas where the soil may be compacted, it will often be necessary to physically improve your soil before you can grow deep-rooted plants. Physical improvement of soil involves tilling to break up compaction and provide aeration and adding organic matter to keep soil porous. In addition, it may be necessary to chemically improve the soil with nutrients or other materials. Landscape architects emphasize that both kinds of soil improvements are important to developing healthy, deep roots, and that heavy fertilizing will not compensate for insufficient physical soil preparation. Before landscaping, take a sample of your soil to your local county Extension office for testing. Your county Extension agent will provide you with a recommendation for lime and fertilizer based on the analysis. The soil test report will give you information on pH, nutrients, volume weight, and humic matter as well as recommendations for correcting any deficiency the analysis reveals. Your goal in soil analysis is to create an ideal soil environment for the expanding root system. An ideal soil has good aeration and drainage, yet holds adequate moisture and nutrients for optimum root growth. If your soil is deficient in phosphorus, potassium, calcium, or magnesium, recommendations will be made for improvement. However, the lab analysis is not useful for sulfur, nitrogen, and boron. You may want to add a commercial fertilizer such as sulfate of ammonia or composted manure to supply both nitrogen and sulfur (Wade et al., 2002; Welsh, 2000).