Calcium performs many required functions in the growth of plants and the production of fruit, seeds, pollen and more. It’s a key nutrient for soil quality, plant health and resistance to disease and pests. Plants will not grow without adequate calcium. It is also vital to the delivery of other nutrients, helping to make them available and get into the plant. Calcium helps nitrogen already present in the soil to become more available to the plant. This is one reason crops green-up when gypsum or limestone is applied.

There are many deposits of limestone throughout the world. In agriculture, the most commonly used form to quickly deliver calcium to soil and plants is calcium carbonate (CaCO3). Dolomite limestone (CaMgCO3) can also be used, but must be finely ground, and not applied where magnesium is high. Calcium carbonate qualifies as “high calcium limestone” when there is less than 6% magnesium present.

In the 1700’s, farmers saw the benefit of adding calcium to their soils. They made their own amendment by burning limestone rock in kilns to release some of the carbon- thus creating “quick lime”. It may not have taken long to discover that adding water to this quick lime helped to stabilize it and reduce its tendency to burn skin and plants. Thus, “hydrated lime” was then applied to crops, trees and berries. Fast-forward to modern ag, and we are once again using the stable and abundant limestone rock “calcium carbonate”, finely crushed to facilitate application and readily available to be used by plants.

Limestone may be best known for its ability to raise low pH (potential hydrogen). For plants, a healthy balanced pH is generally around 6.4 or 6.5. Some acid is always needed for the breakdown of soil nutrients, but at pH levels above that it becomes more difficult. Generally speaking, gypsum will not raise or lower pH, since the proportion of carbonate (present in limestone but not in gypsum) is what removes the excess hydrogen from the soil. The action of adding calcium carbonate to soils high in hydrogen produces water and carbon dioxide. (CaCO3 + 2H= H2O + CO2)

OSA High Calcium Limestone is raw, crushed, screened, and certified organic. It is locally sourced and an assay is available. Limestone is priced by the ton and delivered to your location. Delivery charges apply.

Long employed by home gardeners, humus, in the form of compost and manure, has shown its worth building soil health and benefiting plants. Retaining water, reducing evaporation, reducing runoff, providing pathways for water and minerals to move through the soil, feeding biologics and microbes, sequestering carbon and nitrogen- these are a few of the ways it performs. The percent of organic matter in your soil has a huge impact on its moisture-holding capacity and its soil structure.

Compost and manures share similar functions in the soil, but they also have individual benefits. Compared to manure, compost is a slower-release material. The chief components are carbon, calcium and nitrogen. Minerals in compost will vary by source. Manure, with its primary nutrient being nitrogen, releases its components more quickly than compost. However, conditions apply when expecting manures to provide nitrogen.

In combination with gypsum or soft rock phosphate (both strong calcium providers) humus provides many nutrients in forms readily available for plants to take up. The positive ions in calcium hook to negatively charged nutrients to hold them in the soil instead of being easily leached out which can occur in dense soil with poor structure. In chatting with farmers who had livestock in the past, it’s common for them to notice for years afterward the improvements manures and composts have provided.

OSA Manures and Compost products are local and regionally sourced. Organic and non-organic sources for compost, compost fertilizers, and manures may be seasonal. Prices and availability varies. Delivery charges may apply.

Humates are large complex molecules made up mostly of stable carbon. The source of humate is basically the same as peat and coal-layers of dense humus compressed over long periods of time. The resulting molecules carry many weak electrical bonds that can hold nutrients and minerals. Like the weak bonds holding calcium and sulfur in gypsum, nutrients loosely held by humate molecules are easily taken up by plants. Humate is an excellent addition to any fertilizer or amendment and very little is needed per application.

OSA Humate is very finely ground and screened. It is sourced from the inter-mountain west. Assay available. Priced by the pound or ton. Delivery charges may apply.

Known as “The Calcium Helper”, boron is absolutely essential for plants to metabolize calcium. It is required by magnesium and phosphorus as well. Too much however, is toxic. The balance between too little (it’s easily leached out of soil) and too much (over 5 ppm is too high) should be monitored by soil testing and scrutiny of your crop. Boron is a structural element of the cell walls of plants, and is a big player in the delivery system of sugars. The higher your pH, the less boron is available to your plants.

OSA offers boron in a stable granulated form coated with borate that resists crushing and dust, but 100% soluble in water.

OSA Boron is a dry, granulated and coated product sourced from the west coast. It is OMRI registered (certified for use in organic agriculture) and contains 15% elemental boron per pound of product. An assay is available. Boron is priced by the pound and available blended in our gypsum product, or picked up in 50 lb bags at our scale at our scale yard location in Arden, WA.

Phosphorus (P) supplies the energy for plants. It’s critical in the photosynthesis process where light is converted to chemical energy inside the plant. When too little P is available, or when the soil has adequate phosphorus but it’s tied up with other elements, the whole structure of the plant suffers, especially root growth, and the quality of the intended harvest is diminished. High-yield crops require a lot of phosphorus overall, and throughout the entire growing cycle of the plant.

Called “The Reluctant Nutrient”, as an element, phosphorus has a triple negative charge. It is highly motivated to attach itself to other more positive elements like calcium, iron and aluminum. Soil may contain thousands of pounds of phosphorus per acre, but only 30 to 50 pounds may actually be available to the plants (Zimmer, 2017). Sandy soils can be much worse.

Commonly used dry and liquid commercial fertilizers such as DAP,  phosphoric acid or super-phosphate provide a very soluble and immediately available source of phosphorus. However, research has shown that all the P may be tied up in just days and then it becomes unavailable. Or worse, it may be lost through topsoil erosion and become phosphate pollution.

The solution to the phosphorus dilemma is to provide a slower release source that plants can use consistently over time, one that soil microbes and biologics can release with their digestive acids. Soft Rock Phosphate is this source.

Also known as colloidal phosphate, soft rock phosphate is a mined product- a mix of phosphate rock, minerals and clay. The calcium content is about the same as the phosphate content, in this type of rock, generally 18 to 19%.

Compared to commercial phosphate fertilizers, soft rock phosphate really shines in acid soils.  It brings along its own calcium (which is low in acid soil) and many other micro nutrients. The P remains available over the long term, and it doesn’t leach. For crops that need immediate phosphorus treatment, a soluble P application followed by soft rock phosphate is the way to go. Even better, once your soil is built up with the proper amount of soft rock phosphate, it will continue to be available- feeding the plants and soil.

OSA Soft Rock Phosphate is a raw, dry and screened product sourced from the midwest. An assay is available. Priced by the pound or the ton, delivery charges may apply.

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