SKU: 29948814507
calcium phosphate fertilizer for plants

calcium phosphate fertilizer for plants Calphos

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Description

calcium phosphate fertilizer for plants CalphosCalphos Soft Rock Phosphate is a natural phosphate fertilizer made from finely ground soft rock. It is OMRI listed for organic use and is especially effective in acid soil and slightly acidic environments. This product is a reliable source of calcium phosphate and trace minerals that gradually release into the soil. The slow release of nutrients supports healthy plant growth, improves soil fertility, and provides benefits that last for the long term.

Calphos Soft Rock Phosphate is a natural phosphate fertilizer made from finely ground soft rock. It is OMRI-listed for organic use and is especially effective in acid soil and slightly acidic environments. This product is a reliable source of calcium phosphate and trace minerals that gradually release into the soil. The slow release of nutrients supports healthy plant growth, improves soil fertility, and provides benefits that last for the long term.

Why Use Calphos Soft Rock Phosphate?

Unlike many synthetic phosphate fertilizers, Calphos is a natural phosphate source that feeds plants steadily over time. Because it gradually releases phosphorus, it does not wash away easily with rain. Instead, it stays in the root zone, helping plants build strong root systems and maintain healthy soil structure. This makes it an excellent choice for growers focused on enhancing soil naturally while reducing the need for frequent reapplication.

Calphos contains about 20% P₂O₅, with 3% immediately releasing phosphorus for quick results and the rest breaking down slowly for long term benefits. It also provides around 18% calcium, which helps maintain proper soil pH and supports optimal growth.

Key Benefits of Calphos Soft Rock Phosphate

  • Balanced Nutrition: Supplies phosphorus and calcium phosphate in a form that plants can use steadily.
  • Slow Release Performance: A true slow release fertilizer that feeds plants for up to 5 years.
  • Supports Healthy Soil Ecology: Works well when mixed with organic matter, encouraging microbial activity and improving soil structure.
  • Minimizes Nutrient Loss: Reduces leaching and keeps nutrients available in the root zone.
  • Versatile Applications: Useful for row crops, orchards, trees, and general soil-building programs.

Application Guidelines

For best results, always start with a soil test to understand the nutrient needs and recommended application rates for your soil type and crops.

  • Field Use: Spread about 1 ton per acre on phosphorus-deficient or acid soil.
  • Tree & Orchard Use: Apply 1–10 lbs of Calphos in each planting hole, mixing it well with the surrounding soil.
  • Pre-Planting or Blending: Incorporate into the soil before planting or blend with compost and organic matter for a balanced amendment.

Because Calphos gradually releases nutrients, it provides both immediate and lasting results, reducing the need for repeated fertilizer use.

A Sustainable Choice for Plant Growth

Calphos Soft Rock Phosphate is derived from ancient marine deposits, giving it a natural balance of phosphorus, calcium, and trace minerals. By combining these nutrients, it helps create fertile soils that support healthy root systems, vigorous crops, and healthy plant growth.

Its natural composition makes it one of the most reliable phosphate fertilizers for gardeners and farmers who want to focus on enhancing soil rather than relying on quick fixes.

Why Gardeners and Farmers Choose Calphos

  • OMRI-listed for organic production.
  • Reliable, natural source of phosphorus and calcium phosphate.
  • Excellent for slightly acidic soils and acid soil.
  • Improves fertility while supporting healthy microbial life.
  • Provides both quick and long term nutrient availability.
  • Ideal for row crops, fruit trees, and soil-enrichment programs.

Available Sizes

This 50 lb bag is perfect for larger gardens, farms, and orchards. For smaller applications, Calphos Soft Rock Phosphate is also available in a convenient 5 lb bag.

For smaller applications, Calphos Soft Rock Phosphate is also available in a 5 lb bag.

Explore more options in our High Phosphorus Fertilizer Collection or shop the full range in Fertilizer & Growing Supplies.

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
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Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
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SKU: 29948814507

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Tee & Cee
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★★★★★ 5
Top quality
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This Siless Hybrid 3-in-1 sound deadening mat is easy to work with and feels high-quality. The butyl material is thick and pliable, making it simple to cut and fit into doors, floors, or panels. After installation, road noise and vibrations are noticeably reduced, and it also seems to improve the overall cabin feel. No bad smell. At 25 sq ft per roll, it’s a good value for anyone looking to dampen noise and improve car acoustics. Overall, a solid, effective option for automotive soundproofing. Used on a Fiesta ST.
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Reviewed in the United States on February 15, 2026
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Andy
Bozeman, US
★★★★★ 5
Made a big improvement in cabin noise—highly recommend
Model: SLH20025
Siless Hybrid made a huge difference in reducing noise in the floor of my truck cabin. In some areas, there was basically just bare sheet metal between the inside and outside, so adding this really helped the truck feel more solid and noticeably quieter on the road. I used Kilmat on the doors, and honestly I wish I had used Siless Hybrid there too, but it was too late by the time I realized the difference. This material is very sticky, easy to cut, and simple to apply, which made the install pretty smooth. Just a heads-up: the tacky side gets messy and will bond to clothing really easily, so be careful during installation. Overall, I’d definitely buy it again—great product with real results.
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Reviewed in the United States on December 2, 2025
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AmazinFrank
Fort Morgan, US
★★★★★ 5
Very good product at a fair price
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Very good sound deadener and heat shield, it is a bit sticky to work with, but easy to shape and cut
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Reviewed in the United States on April 19, 2026
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Eric Caldeira
Whiting, US
★★★★★ 5
I wish I had Siless 20 years ago!!!
Model: SLH20025, Model: SLH20025
I have installed all kinds of insulation in vehicles over many years. I only needed to purchase 2 boxes to complete the entire interior siding of my 2025 chevy express, what a great value! I wanted to insulate my locksmith van for sound and heat. The sound reduction virtually eliminated the road noise. These panels also look amazing. It got up to 110F in the sun with the doors closed. After adding Siless insulation the temperature maxed out at 97F. That is a massive difference. Plus, I didn't even finish with the roof before testing. Siless Hybrid 3in1 was extremely easy to cut and adhere onto metal panels. I'm impressed with the quality of the individual panels and the adhesive is not toxic smelling compared to some others. My favorite thing about these panels is you can actually take them off and readjust them before they finally stick and they do not leave any black residue behind when you pull them up to adjust them. All I needed was a heat gun, knife and a roller to complete this job. The size of each panel is perfect, you can handle them with ease. I probably won't need your product again for a while, but when I do I will definitely be back.
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Reviewed in the United States on September 21, 2025
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Mark Kadrich
Grantham, US
★★★★★ 5
Works well and is easy to install.
Model: SLH20025, Model: SLH20025
I was sound and heat insulating a generator bay in my class A RV so I did three tests before and during material application: I did a sound level test to see how effective the material was for my application, a "stickiness" test, and a flammability test. This was indoors on a dry 78°F day. From beginning to end, the entire process, including testing, took 5 hours to install 25 sqft or material in a very complex area. One hour for cleaning, 3 hours for installation, and 1 hour for test setup and testing. Using a sound meter, I took before and after readings and determined that I reduced the sound level by 2.2 db (40% energy decrease) with a noticeable decrease in sound and frequency. The generator bay is located under the master bedroom in the aft portion of the coach. The sound went from a rattling, vibrating generator noise to a more tolerable low level rumble. The material was easy to apply. I did some testing prior to application and determined that surface preparation is key. I cleaned my painted metal surface and then degreased with acetone and the material stuck well. Be careful and purposeful when you apply the material because once it was stuck to the metal, it was quite difficult to remove or reposition. Since it was going to be installed into a gasoline powered generator bay located under our sleeping quarters, I did some flame testing to determine the level of risk. Although not highly flammable after installation, my testing revealed that the PE used will catch on fire under certain circumstances. In order to reduce the risk, I used aluminized duct tape to ensure that all the edges were sealed and the PE was not exposed to direct flame in the event of a fire. I also decided to install an automatic fire extinguisher as an added precaution. In all fairness there should be one installed in the generator bay anyway. All in all, I am very satisfied with the product and the results. I have recommended this product to my other RV owner friends.
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Reviewed in the United States on April 13, 2025

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