Simple Mushroom Substrate Recipe – BucketTek

Looking for the easiest way to make mushroom substrate? You’ve come to the right place. The BucketTek is a simple method to make your own mushroom substrate at home with very little effort.

Fruiting your spawn to bulk substrate doesn’t have to be hard. Although there are many bulk substrate recipes online, this preparation method is simple, straightforward, widely available ingredients, and does not require pasteurization, an autoclave, or any expensive equipment.

This mushroom substrate recipe is based on the BucketTek method, which is not true pasteurization, yet is extremely effective because we are using non-nutrient-containing ingredients (Coir and Vermiculite). Keep in mind that this recipe may be modified by using additional ingredients such as worm castings or manure, but when using these additives, it is smart to perform full pasteurization before use.

Easy Mushroom Substrate Preparation Instructions:


  • 1 Brick of 100% Natural Coco Coir. (650grams)
  • 2 Quarts of Vermiculite
  • 1 cup of Gypsum – This ingredient is optional but provides calcium and sulfur, which is needed for healthy mycelium growth, and also acts as a pH buffer.
  • 5 Gallon Bucket with Lid – Find this at Home Improvement Stores
  • 4 Quarts (one gallon) of Boiling Water. Tap water is fine, filtered water is better.
  • Optionally: Substrate additives to reduce the likelihood of contamination. MGP Plus is our go-to.


Step 1: Place the coco coir into a five-gallon bucket. When using compressed coir bricks it is recommended to break up the coir prior to hydrating it.

Step 2: Add 2 quarts of vermiculite to the 5-gallon bucket.

Step 3: Place a large pot on the stove and add 4 quarts of water. Turn the burner to high heat and add gypsum to the water. Wait for the water to reach a boil, and allow the water to boil for 5 minutes.

Step 4: Remove the pot from the burner and use a large spoon to stir the gypsum/water mix. Pour the hot water over the dry ingredients in the five-gallon bucket.

Step 5: Place the lid on the bucket and allow it to sit for 10 minutes. Once 10 minutes is up, remove the lid and stir up all of the ingredients using a large spoon. Be careful, the substrate will be very hot and steam will be released once the lid is opened.

Step 6: Place the lid back on the bucket and allow the substrate to cool overnight (4-6 hrs).

Step 7: If using an additive to reduce the likelihood of contamination, you can add your substrate additive per the instructions.

Step 8: Use it!

Have you had success with this recipe? If so, we would love to hear from you. Leave a comment in the box below!

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