Rock Phosphate

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

First Option A for Rock Phosphate contains 7% immediately available Phosphorus (P20), Total Phosphorus is 20% averages 30% Calcium (Ca)

Second Option B for Rock Phosphate contains 3% immediately available Phosphate (P20), Total Phosphorus is 20% averages 20% Calcium (Ca)

Both options offer 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.



4 Reviews Hide Reviews Show Reviews

  • 5
    Happy I found it

    Posted by Teri Henry on 31st May 2021

    I plan to make my own soil for a large planter made out of an upright 55 gallon drum. I’ve not found this anywhere else. Happy I found it.

  • 4
    Rock phosphate

    Posted by James Stagner on 7th Jan 2021

    Great company fast delivery

  • 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