Gypsum Tutorial & CVG Calculator

Welcome to our Magical Gypsum Tutorial page! First, we'll take a minute to explain to you what you bought: 

Magical Gypsum is Lab Grade Gypsum mixed with Biochar, Humic Acid, Sucrose and MGP Microbes. This means not only do your mushrooms benefit from a great source of calcium and sulfur/a superior PH buffer - they also get carefully curated ratios of naturally occuring carbon and other immediately accessible nutrition from plant matter in advanced states of decay, ready to be absorbed into your mycelial network. 

If you purchased Magical Gypsum on Amazon and love it, leave us a 5* review by clicking here and send a screenshot to to receive a free MGP Plus, MGP Pure, or Magical Gypsum.

Below you will find instructions, explanations & a useful CVG ratio calculator, which shows you exactly how much of everything you need for the perfect CVG substrate. TO USE THE CVG CALCULATOR enter your desired hydrated substrate weight, and click on the "calculate" text. 


Desired Hydrated CVG Substrate Weight

Desired Hydrated CVG Substrate Weight

Material Amount
Coco Coir
Magical Gypsum

How to Use in Substrates:


Add Magical Gypsum to your CVG, Manure or other substrate at a ratio of between 5-10% dry weight - we recommend 10%. For instance, in a 70/20/10 CVG substrate, you would have 700 grams of coco-coir, 200 grams of vermiculite, and 100 grams of Magical Gypsum per kilogram of dry substrate material.


When used in a coco-coir substrate, it is best to weigh out the coco-coir first, add water to the coco-coir to hydrate/break it up into loosely packed fibers, and then add the vermiculite and Magical Gypsum and mix together - this ensures a more even mix of all ingredients.


Do We Recommend Pasteurizing or Sterilizing Substrate?


Pasteurization vs Sterilization of substrate material is a debate as old as hobbyist mycology. At DrMyc, we strongly believe science points towards STERILIZING substrate, even horse manure, and re-introducing a curated population of microbes, such as our MGP mix. Pasteurization has very few benefits, and is more likely to add contamination into your process. Sterilization produces a blank canvass of nutrition for your Mycelium + Synergistic Microbes to colonize and dominate.


To Sterilize - add your hydrated substrate into a grow-bag or ziploc bag - add to a pressure cooker, autoclave or deep kitchen pot. In a pressure cooker or autoclave, PC at 14 psi for 2 hours. In a deep kitchen pot, bring water to a boil - simmer for two hours. If you want to get really technical, use a thermometer to ensure the core temperature has exceeded 270 *F for at least 1.5 hours. Wait until the substrate is cool to the touch before spawning to bulk, otherwise you will kill your Mycelium.


Once you have sterilized your substrate, the MGP microbes will have been killed off, and you will need to reintroduce them following this guide here.


Using Magical Gypsum with Grain Spawn


One of the best transitions a hobbyist mycologist can make when aspiring towards reliable, consistent production is to create their own grain spawn - and one of the best adjustments to this process of creation is using Magical Gypsum as part of a 24 hour grain soak.


Why is a 24 hour soak necessary/recommended? 


Bacteria and fungi often form resilient reproductive units, called spores or endospores. These spores are hyper-tough, and can survive extreme temperatures and pressures while dormant. The 24 hour grain soak germinates these spores/endospores, allowing for them to be killed off with a higher % of certainty, meaning your mushrooms have a lesser likelihood of fungal/bacterial contamination.



Add 20 grams (0.7 oz) of Magical Gypsum per kilogram of dry grain (2.2 lbs) into a food grade bucket. Add water until the grains are covered, then add more water to the bucket until the water submerges the grains by 4". Stir contents of bucket enthusiastically to homogenize and aerate. Loosely cover the bucket for 24 hours. Ideally use non-chlorinated water for this process.


What are the Benefits of Doing This?


Beyond the aforementioned germination of spores/endospores, this grain soak will hydrate grains perfectly, while coating them in beneficial secretions and nutrients which Hyphae will love. During the grain soak, MGP microbes will enter their exponential growth phase, secreting their useful metabolites which will survive sterilization (unlike the microbes). All said and done, your jars/bags/experiments will colonize at a faster rate, and have less chance of contamination when using Magical Gypsum + a 24 hour soak.


Thanks for Reading & Being the Best Part of DrMyc

We love you guys, so thanks very much for being the best part of our company! If you love us and our products, please leave us a 5* review on - it helps us reach more people, facilitate more innovation, and makes our lives easier. 

❤️ the DrMyc Team.