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This is an awesome product you can make from ingredients found in your kitchen. It is a nutrient solution for plants just entering the flowering cycle. There is an overlapping activity of Phosporous and Potassium during flowering. In natural farming, we apply calphos before the flower initiation to support the eventual fruit. In simplistic terms, we use Phosphorous to address the root system, which will enable the plant to access better water and nutrients from the soil to support the critical changeover as manifested by flower initiation.


We use Calcium to strengthen the plant in preparation for heavy flowers/fruits. Thus, natural farming emphasizes Phosphorus and Calcium during the changeover period from growing to flowering/fruiting, and this provides for that need.

***For an illustrated example of this recipe, check out the farm log here. The flog has all kinds of good stuff, sign up to get the updates via email!***


How to Make

  1. Collect a bunch of eggshells and wash to remove inside filaments. Remember, you can also use bones and other good sources of calcium like seashells, clams and oysters, etc. Likewise, if you only want calcium, even limestone can be used, or simple lime.

  2. Pan fry the eggshells. Fry until some are brown/black, some white. The burnt shells are your Calcium source while the white are the Phosphorus source.

  3. After roasting the eggshells, grind them up. You can do it manually, with a mortar and pestle, throw them in a blender or electric coffee grinder, etc.

  4. Add them to a jar and add 5 parts vinegar by volume. For example, if you have 1 cup ground shells, add 5 cups vinegar.

    • The acid in the vinegar helps digest them. You will notice bubbling as this process converts the ingredients to liquid calcium phosphate.

  5. Wait until tiny bubbles disappear

  6. Seal the jar and ferment for 20 days.

  7. Filter into another jar

  8. Now you’ve made your own Calcium Phosphate


How to Use

Mix 1tbsp per gallon


  • spray on leaves during transition phase to flower, and when fruits are large and mature

    • Transition Phase: Induces flowering, eases nutrient demands of transition phase, strengthens flowers

    • Mature Fruit: Strengthens plant stems, leaves, fruits, helps fruit mature properly for optimum sweet flavor!



  • Feed to animals during breeding time and during pregnancy. Helps breeding efficacy and litter success rates. Woohoo!

Cal Phos

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