Sandy Loam vs. Cactus Soil

Characteristics

• Loam soils are a nearly balanced blend of silt, clay and sand particles, making them the most desirable garden soil to have on a property. Loam soils combine decent mineral composition -- often a high fertility -- with good water drainage and air porosity. A sandy loam has more sand particles in the blend, making the soil a bit more grainy, but it is still fertile with good drainage and particle structure.
  Cactus soil, as created for use in containers, is a sand- or grit-based medium. Perlite, coir or peat may be added to provide organic material to hold moisture and supply nutrients.

Soil Insight

• Sandy loam occurs naturally. Gardeners strive to modify their landscape soils to become as close to loam as possible, because it's such an ideal garden soil. While various succulent and cacti plants grow best in well-drained soils, not all "cactus soils" in nature are similar. In some regions, the arid soils may be very high in sand and low in clay, or more of a loam with lots of grit. Succulent plants survive because the soil is not too wet or drains fast enough to prevent the plant roots from suffocating and rotting. Manufactured cactus potting mix is a sterile, ideal growing medium engineered specifically for growing a broad array of cacti and other succulent plants, particularly in containers.

Uses

• A wide array of plants will prosper in a fertile sandy loam topsoil. Many cacti and succulent plants will thrive as well, as long as the topsoil drains thoroughly and doesn't remain too moist. Outdoor topsoil may be amended with organic matter to improve fertility. Topsoil, such as sandy loam, is not good to use in containers, as it contains microbes and other organisms, including traces of fungi or other potential diseases. Topsoil also compacts when in a container because of the frequent cycles between watering and drying out. Cactus potting mixes are ideal for containers because they don't compact and always provide appropriate air porosity and water drainage.

Recommendations

• If your garden comprises sandy loam soil, you are fortunate. Cacti and succulents will grow well in sandy loam, especially if you amend sandy loam with coarse organic matter and grit to improve drainage, fertility and porosity. Alternatively, you may mound the soil to ensure excellent drainage before installing cacti and succulent plants. Special-blend or mixed cactus potting soil isn't practical -- or feasible -- to use in a landscape. Use cactus potting mixes for container plantings.