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We are now offering the BuildASoil Calcium Phosphate.


Calphos™ is a natural, untreated soft phosphate with colloidal clay containing valuable minor minerals in addition to phosphorus. It is not acid forming, will not cake or harden and spreads easily through any type of lime, phosphate or fertilizer spreader.

Calphos™ is not a complete fertilizer and should never be used as such. It is an excellent source of phosphate that is being used profitably for farmers who are interested in getting a dollar’s value for a dollar spent. When applied to the soil Calphos™ adheres to and becomes a part of the soil. It will not leach and it will not revert and once applied remains in the soil until used by the plants. Calphos™ contains no harmful acids and encourages growth of soil bacteria and earthworms.

Warning: Calphos can cause a abundance of toxic metals such as cadmium. Continual top dressing in a no till garden may not be advisable. We like this product but we only recommend using it minimally.

Select your item in the drop down menu above:
4.5 lbs (10 - 15 Cups) - Small Bag = $15.00 + FREE Shipping
15 lbs (45 - 50 Cups) - Large Bag = $30.00 + FREE Shipping
30 lb (90 - 100 Cups) Food Grade Bucket = $50.00 + FREE Shipping
50 lbs (140- 150 Cups) (50 lb Bag) = $50.00 + Paid Shipping

Heavy Metal Report from Washington

MSDS from Manufacturer

Top Dress with CalPhos and gypsum along with worm castings to ensure the proper nutrients are available as you go into flowering.

 Excerpt from Dr. Carey Reams:

Soft rock phosphate is found in central Florida, in the Dunnellon area, in what is known as the "hard rock" section. Many thousands of years ago, nature left these phosphate residues from the teaming of marine life which once populated the region. Rock and clay rich in phosphorus was the result. When mining of the rock started almost a century ago, the clay on and between the big boulders was washed into pits and drying beds. These pits and beds, are, today, the deposits of soft rock phosphate. The phosphate and other nutrients in soft rock phosphate are in colloidal compounds. Compound colloids are not water soluble, but they stand in suspension in water and create the impression that they are. They will stay in suspension, just like the dust particles that one sees in the air when the sun shines into a room. Compound colloids are so small that one cubic inch of them, equally dispersed, will cover 7-1/2 acres. They are so fine that they will fit into the holes in water, between the molecules of water. They are 100% available to plants, and they will not leach out of the soil. A compound colloid is like a small bearing in the soil; it fits any plant frequency, and allows nutrients to go into a plant without resistance. "A plant food in colloidal state appears most active and efficient and seems to have remarkable powers," says Milton Whitney, Chief of Bureau of Soils, U.S. Department of Agriculture. Elements in a compound colloid are non-poisonous and non-toxic and will not harm the bacteria in the soil.


Top Dress with CalPhos and gypsum along with worm castings to ensure the proper nutrients are available as you go into flowering.

Use at 1/4 Cup per cubic foot of soil mix or topdress. 


4.5 lb - Small Bag:

Dimensions: 8 x 5 x 3.5

Weight: 4.5 lbs

15 lb - Large Bag:

Dimensions: 11 x 6 x 5.3

Weight: 15.0 lbs

30 lb Food Grade Bucket:

Dimensions: 12.5 x 12.5 x 15

Weight: 30.0 lbs

50 lb Bag:

Dimensions: 21 x 12.5 x 5.3

Weight: 50.0 lbs

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