Rock Phosphate

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1.00 LBS
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This is a granular Rock Phosphate that is one of the best natural sources of phosphorus (P) and calcium (Ca). 

Rock Phosphate contains 7% immediately available Phosphorus (P20), averages 30% Calcium (Ca) and possesses numerous trace minerals for up to 5 years after application, depending on the crop and soil conditions.    Phosphate is immediately available to plants and will act as a long-term source of phosphorus.  Rock Phosphate should be plowed under or turned into the soil.  Unlike chemically made phosphates, rock phosphate is insoluble in water, will not leach away, and therefore is long-lasting.

Annual plants absorb up to 60 percent of its total phosphate needs within the first few weeks of its life.  If it does not receive phosphate then it is always behind and never catches up. Rock phosphate used directly under the seed or transplant at planting time is the very best method of application, especially in low acid or high alkaline soils.  It is not as critical but still beneficial in slightly acidic to neutral soils.  It is almost impossible to overuse soft rock phosphate, you can grow beautiful plants directly in it without any harmful effects.

Rock phosphate should be applied and worked into the soil prior to planting along with other organic amendments.  In alkaline soils, apply the phosphate directly under the seed or transplants so the small roots don’t have to search for it.  This is especially important in the spring.

Application Methods:
  • Amending soil:  Apply up to 5 lbs. / 100 sq.ft. or 1 ton / acre on phosphate deficient soils, and less on fertile soils.  If planting in rows, mix with the seed or starter plant and apply up to 1 lb. per 50 ft of row.
  • Trees and perennials: Apply 1 - 10 lb. per planting hole, depending on plant size.
  • Transplants: 1 - 2 tablespoons per 4-6" planting hole.
  • Potted plants: Mix 1 teaspoon per 2" pot diameter with potting soil before planting.

Nitrogen (N)............ 0%

Phosphorus (P)........ 7%

Potassium (K)......... 0%

Calcium (Ca)........ 31%

Iron (Fe).................. 1%

Silica (SiO2)...........26% 

Total Phosphorus.. 20%



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  • 5
    Hard to find in local outlets

    Posted by Pat on 26th Oct 2018

    This product is not easy to find locally. This is a great company to do business with

  • 5
    Soft rock phosphate

    Posted by verified customer on 4th May 2018

    I use this to good effect growing peppers. Worm castings, soft rock phosphate, and Azomite are proportioned 4:2:1 and put into the bottom of the transplant hole. A layer of soil separates roots freshly dusted with mycorrhizae. You want that beneficial fungi to establish before reaching the phosphate source. This method has been working really well for me. I'm doing a lot soil-wise. This is one key ingredient. Just wished I could pick bulk items up to avoid shipping. This company has done quite well as a reliable supplier.