Rock Phosphate

(3 customer reviews)


Long-term, slow-release calcium and organic phosphate. builds up native and depleted soils.

Not Avail in California


Product form:

Dry powder

NPK analysis:


Primary function/use:

Slow-release phosphate fertilizer.

Other product highlights:

A good alternative to bat guano. Product is 20% total phosphate and 3% available phosphate.

Product designation:


Best suited for:

Well suited for amending and enhancing the soil.

When and where to use:

Start with early season soil preparation and supplement as needed during grow cycle.

How to apply:

Sprinkle evenly around base of plant or till into soil before planting.

How to mix:

Vegetable Gardens: 4-6 lbs. per 100 sq. ft.

Trees & Shrubs: 1 lb. per one inch diameter of tree.

Perennials & Roses: 1/2 cup per each new plant


Ensure bag is properly sealed and stored in cool, dry, dark place.

Additional information

Weight N/A

3 reviews for Rock Phosphate

  1. Chad

    Phosphorous isn’t very mobile in soils, but this is an affordable way to premix and supply ample phosphorus for big blooms. Not recommended as a top dress, mix in before planting.

  2. JJayW

    A great product if you have a plant that is root heavy. My hops and Flying Dragon (Citrus trifoliate) are really happy with it.

  3. Carol Nelson

    When added to my garden fertilizer mix, my plants bloom and produce at an amazing rate (side dressing along rows). It’s nice to have an affordable source for soft rock phosphate and all the other ingredients in my fertilizer. The delivery time is excellent. My rural postal delivery guy even knows if it’s a big heavy box from Kelp4Less just put it on the table in the garden shed!

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