The product

Calphos colloidal soft rock phosphate.

A soft phosphate clay from ancient marine deposits, mined and milled in Florida. It carries phosphorus, calcium, and the trace minerals that come with the material, and it releases slowly instead of all at once.

At a glance

MaterialColloidal soft rock phosphate

Common labeling0-3-0

CertificationOMRIListed

GradesPowder & granular

Understanding the mineral

What colloidal soft rock phosphate actually does.

Slow, steady release

About three percent of the phosphorus is available immediately for quick plant response. The rest is released gradually, providing sustained nutrition through the season and into the years ahead.

Phosphorus and calcium

Independent testing puts Calphos at about 22 percent total P₂O₅ and 21 percent calcium, plus the trace minerals that come with the clay. Phosphorus for roots and seed, calcium for soil structure, in one material.

It stays where you put it

Unlike highly soluble synthetic phosphates that can wash away, this natural material resists leaching. It builds a reserve of long term fertility instead of a short term spike.

From deposit to pellet

How Calphos is made.

Every step happens under one roof in Ocala, which is how we hold purity and consistency from the ground to your gate.

The result: vigorous crops

Mined from the original deposit

We source our colloidal phosphate from the original tailing ponds created during hard rock phosphate mining in the 1940s, among the cleanest phosphatic clays in the region.

Dried and finely pulverized

The material is dried and milled into a fine powder. This is our standard formulation, ground to pass a 200 mesh screen.

Formed into durable granules

That same powder is bound into pellets through a proprietary process. The granules resist breaking into dust in transit, then disintegrate gradually in the soil.

Packaged and shipped

Finished product moves out in bulk, one-ton totes, and 50 pound bags, ready for truck or rail to anywhere in the country.

Two grades

Pick the form that fits your operation.

Grade 01 · Standard powder

Finely milled, fast to react

Our standard formulation is a fine powder, ground to a 200 mesh fineness. It reacts readily at the soil surface and blends cleanly into custom fertility programs. A grower's choice for banding, blending, and building base fertility.

Ideal for blending with other inputs
Maximum surface area for reaction

Grade 02 · Granular

Durable pellets, slow release

The same pure powder, formed into granular pellets with our proprietary binder. Built for ease of handling, blending, and spreading through conventional equipment, with a slow release as the granules break down.

Low dust, easy to spread
Works with standard fertilizer equipment

Guaranteed analysis & specs

The numbers behind the name.

Calphos is derived from untreated, soft phosphatic clay. The phosphate and calcium figures below come from independent laboratory analysis by Thornton Laboratories of Tampa, Florida. Because it is a natural mineral, trace elements come with the guaranteed nutrients, so we test for those too and share the results (see below). A current certificate of analysis ships with every order.

200

Mesh fineness

90% wash or 30% dry through a 200 mesh screen.

Lbs per cubic ft

Typical bulk density of the granular grade.

Guaranteed analysis

Total Phosphate (P₂O₅)22.21%

Available Phosphate (P₂O₅)3%

Calcium (Ca)21.05%

Trace mineralsNaturally present

Phosphate and calcium results from independent laboratory analysis, Thornton Laboratories, 2025 (Lot B). Labeled 0-3-0 for guaranteed available P₂O₅. Derived from untreated soft phosphatic clay. A certificate of analysis ships with every order.

Third-party tested

We publish what is in the material.

Trace elements occur naturally in every phosphate rock. Rather than ask you to take our word for it, we have the material screened by an independent lab and share the results. The most recent analysis, from Thornton Laboratories in Tampa, is below.

Trace element analysis mg / kg · Lot B, 2025
Element	Result	Element	Result
Arsenic (As)	3.7	Molybdenum (Mo)	1.7
Cadmium (Cd)	3.0	Nickel (Ni)	26
Chromium (Cr)	74	Zinc (Zn)	48
Cobalt (Co)	5.6	Selenium (Se)	< 0.3
Copper (Cu)	9.8	Mercury (Hg)	0.12
Lead (Pb)	9.8

Analyzed by Thornton Laboratories Testing & Inspection Services, Inc. (Tampa, FL) using EPA methods 6010, 7473, and 3050B. Full certificates of analysis, including nutrient and trace-element reports, are available on request for any grade or shipment.

The purity advantage

Calphos is notably purer than comparable products on the market, containing significantly less silica. That purity comes from our sourcing: the original tailing ponds of 1940s hard rock mining, one of the cleanest and most consistent phosphatic clays in the region.

Ready to spec your order?

Request current pricing and a certificate of analysis for the grade and volume you need.

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