Soil Preparation

Soil preparation is an important part of any successful xeriscape and desert garden. Water is only part of what makes a good xeriscape green and inviting. The nutrient content and structure of the soil have a major influence on how well your plants will grow.

The Qualities of Desert Soil

Unfortunately, desert soils tend to be rather poor, with a high content of silt, sand, and rock particles but little organic material. Rich, loamy soils are caused by chemical weathering, but in the desert, there isn't enough water to promote much of this type of weathering. Instead, desert soil is created by erosion, which breaks rock down into sand or gravel that doesn't contain much organic material.

Another problem with desert soil is evaporation bringing salts to the surface. This high concentration of sodium and calcium on the surface of the soil can create saltpans, where almost nothing can grow. Strong winds and lack of moisture also mean that silt and sand particles are easily blown away, allowing the remain soil to become compacted into desert pavement.

All this means that to ensure you give your xeriscape the best possible chance of overcoming these harsh conditions, you'll want to start by making sure your soil is in good condition.

Know where you stand: test the soil

There are several types of soil common to arid climates By testing before you plant your landscape, you'll be better able to determine which plants are best suited for your site and what you may need to do to improve your soil.

Do-it-yourself soil test kits are available at many home and garden centers. These kits let you analyse your soil's pH, but may not tell you everything you need to know. Many local agricultural extension offices also offer, for a small fee, soil tests for both pH and nutrient levels. They may not test for every important nutrient, though, so if there's something specific you want to know, such as your soil's sulfur level, ask for it specifically.

For established landscapes, soil testing can be done in spring or autumn. For new sites, a soil test can be done anytime when the soil is workable. Just make sure your soil is dry when you take a sample, as wet soil can give incorrect results. Overall, autumn is the best time for a soil test because testing centers are less busy and starting in autumn gives you time to prepare the soil for spring.

Once you know the "personality" of your soil, find out what you can do to improve your desert soil.