Soil is vital to the success of any garden. So it’s worthwhile to understand the key factors that can impact its productivity:
Texture. Texture is the relative proportions of sand, silt and clay particles in any soil. It determines a soil’s fitness for growing plants, or its tilth, as well as its nutrient and water-holding capacities. Soils with coarse-grained sand are considered light, while soils with fine particles of clay are heavy. The ideal soil, loam, is a combination of all three.
Structure. Soil particles form into groups called aggregates. Soil structure refers to the way these aggregates are arranged into various sized crumbs and clods. A soil with good structure will have adequate water infiltration, drainage, aeration and overall tilth.
pH.The pH of garden soil is its relative acidity or alkalinity. A soil’s pH influences numerous chemical reactions, including the availability of nutrients considered essential for plant growth. Most crops do best when the soil is slightly acidic to neutral (pH 5.5 to 7.5). Your soil pH can be measured with a soil test kit, readily available at nurseries and garden centers.
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Salinity. Soluble mineral salts dissolve easily in water and can accumulate in soil. They’re usually washed away by winter rainstorms, but they build up in semi-arid Mediterranean climates where rainfall is scant. To make matters worse, drought, fertilizers and irrigation all contribute to excessive salt in the soil. Many plants, such as ornamentals, fruits and vegetables, are damaged by too much salt. The solution is to flush away the salt, which may prove impractical in areas with severe water restrictions.
Fertilizers and amendments. Fertilizers add nutrients to the soil, while amendments improve the soil’s physical or chemical properties. Animal manure can be a source of readily available nutrients while supplying organic matter.
To learn more about soil, attend UCCE Master Gardeners’ Advice To Grow By workshop, 10 a.m. to noon Saturday at the UCCE Auditorium, 2156 Sierra Way in San Luis Obispo.