920 Samoa Blvd, Ste 217, Arcata, CA 95521
(707) 633-8885

Organic versus Mineral Soil

Organic vs. Mineral Soil

There is a BIG difference

Organic Soil: Organic soils are made of Organic materials like peat, coco, and compost. Naturally occurring organic soils can be found in peat bogs and marsh soils. Green house media/potting soil are another type of organic soil

Native/Mineral Soil: These are soils created from the weathering of rock and/or deposition of mineral material by wind or water. Over time soils form into unique mixtures of weathered and layered geologic material. Landscape shapes as well as climate, impact the local soil formation, hence the variability of soil across the landscape. Soil mapping is a technique used by soil scientists to map the variability of soils over a given area. These maps are very useful for any land-based planning or management.

Soil Texture: Soil texture is defined by the particle size make-up of the mineral soil fraction. There are three main soil particle sizes: sand, silt, and clay. Sand is the largest, most coarse particle and clay is the finest, smallest particle. The particle make-up of your soil drastically affects its nutrient holding capacity, moisture holding capacity, and drainage. In turn, this impacts the chemical and biological environment in your soil.

Soil Texture Types

The Soil Type Triangle

Sand, loamy sand, sandy loam –   (See bottom left corner of the Soil Triangle) These are well drained, aerated, and workable for most of the year. They are very light to handle and quick to warm up in the spring. These rapidly draining soils have a tendency to dry out too quickly, so extra watering and addition of organic matter (OM) is often necessary to improve moisture retention. Excessive watering leaches essential plant nutrients from the soil. These soils tend to be acidic and do not have a large nutrient holding capacity and are often referred to as “hungry soils” because they need lots of extra feeding. With careful management, however, they can be among the most productive soil types.

Loam, sandy clay loam, silt loam –  (right hand side of Soil Triangle) A loam has relatively equal parts sand, silt, and clay. These soils have excellent water and nutrient holding capacity, while also having good drainage, the best of both worlds! These soils achieve a good balance between the ability to be very productive with minimal attention.

Clay, sandy clay, sandy clay loam, silty clay, silt –  (top to right side of Soil Triangle) Although these soils are difficult to work with, they are usually nutrient rich with little plant access to nutrients that are locked up in the dense matrix. The main drawbacks are slow drainage, difficult for plant root to penetrate soil and access nutrients, and the effort required to work them. You will need to catch just the right weather conditions to avoid hard work and damage to the soil structure. Using heavy machinery or grazing animals should be avoided, especially when soil is wet.

Learn More

Where is YOUR Soil At?