Making Mushroom Compost

Mushrooms are one of my little peccadilloes – so it was great to come across a good article over at Food from the Garden on creating mushroom compost and using it to grow your own mushrooms – a much more resilient solution than depending on bought Mushroom-growing kits. So that I have a copy in case the original page goes missing I have also reproduced parts of it below the fold, but go here to read the article while it is still there.

The critical factors in producing good quality mushroom compost are:

  1. Very good hygiene to prevent contamination by unwanted microbes
  2. The right proportions of manure and straw
  3. The use of wheat straw rather than any other kind
  4. The generation of sufficient heat to properly pasteurize the compost
  5. An adequate supply of Calcium
  6. An alkaline pH that reaches neutral (pH 7.0) when composting is complete)

The process begins by soaking the straw in water and then leaving it to drain so that it remains only just moist (only a few drops should come out when squeezing a handful).

Manure and Gypsum are then mixed into the straw and the heap formed up. Only poultry or horse manure should be used (other types will not produce enough heat) and the heap should then heat up quickly.

For every bale of wheat straw, use about eight (8) gallons (36 liters) of dry poultry manure (not litter, but actual manure) or Horse manure. As an alternative to mixing, the heap can be built up in layers of these proportions.

Gypsum is used at the rate of 14 lb (about 6.5 kg) per tonne of manure, so a light sprinkling on each layer should suffice. If the compost looks greasy or sticky when turning, simply add more Gypsum (not Lime).

Ideally, a heap should be six feet high in order to quickly develop enough heat, but a compost bin or tumbler could be used to contain and insulate smaller quantities. The compost should then be thoroughly turned on a weekly basis until it stops re-heating and the pH falls to neutral. At this point it should be used immediately so that only mushroom spawn has the chances to populate it.

The process of growing mushrooms is then simply laying the compost into boxes, inoculating it with spawn and keeping it away from sunlight (a shady area is sufficient) and draughts while the fungus grows. The ideal temperature range is 56-60 degrees F (13-15 degrees C). Lower temperatures will only slow growth, but higher temperatures should be avoided.

Air movement that can dry the compost is harmful, but good ventilation is essential since as little as 2% Carbon Dioxide in the air can harm the developing mushrooms.

Once the fungus has filled the compost and pinheads begin to appear, moistened peat ‘casing’ is laid over the top and the mushrooms will begin to grow. They are harvested by twisting them out and the holes are re-filled with casing material.


2 responses to this post.

  1. […] Vegetarian, Recipe, Parsley With two of my recent themes being Hazelnuts from edible hedges and growing our own mushrooms, imagine how delighted I was to find this recipe over at Fungi Perfecti: Shiitake Hazelnut […]


  2. […] to make your own Mushroom Compost over at, even simpler than my previous post on Mushroom Compost: The perfect ’substrate’ on which to grow mushrooms is well rotted horse manure. Either […]


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: