Natural Gypsum coarse grade mushroom supplement grain and substrate

$25.00$28.00 inc. GST

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Gypsum Calcium Sulphate  (CaSO4) mushroom supplement grain and substrate


Our gypsum is a coarse grade and the highest quality available on the market. They come straight from a quarry and are broken up in our facility to at least half their size(1-2mm).


Our gypsum gives you better results than food grade and Bunnings ones, comes without any added ingredients, and is 100% natural, additive and processing-free.


Gypsum may be added at any stage of mushroom cultivation. It is a versatile compound that provides essential minerals for healthier mycelium growth, that is due to its high content of calcium and sulphur, which leads to bigger yields and higher chances of success.  The key features of Calcium sulphate are:


  •  Prevention of sticking and clumping when added to grain spawn, leading to more prominent mycelial points of contact, reducing chances of contamination
  • Increased moisture distribution when added to the substrate
  • Enhanced yields and fruit body formation


Depending on the method, soak, boil and dry your grains and then add gypsum. Mix well and then sterilise.


  • Add 3% of Gypsum of the total dry weight when adding to grains
  • Add 5% of Gypsum of the total dry weight when adding to the substrate

Looking to Make Grain Spawn or more Pre-Mixes? Check what you need in our store

Shipping Cost – The product is shipped via Australia Post using Express Post service for $5.80. If multiple items are in the cart with varying shipping costs, only the highest shipping cost for a product in the cart will be charged.

Handling time- This product has 0 days handling time and is shipped the same day if ordered before 12 pm. However, it’s important to note that if other items are in your cart, the handling time may vary based on the handling time associated with those additional items. Handling time is not guaranteed during the busy holiday period.

Shipping time- Australia Post guarantees express post is delivered the next day in metro regions of Capital cities, but give it anywhere from 1-3 days for this package to reach you. Shipping times are not guaranteed during the busy holiday period.


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