Hydrated lime soak – Fungi Ally and Manna Mushroom farm visit

It seems to be all the rage and fashion the “hydrated lime soak” for oyster mushroom and other fast-growing species production on straw.  This post is for background and  information on the use of hydrated lime to prepare straw to become oyster mushrooms! This is the method in use by Simply Manna Gourmet Mushroom Farms (http://simplymanna.com/), and is a summary of my trip taken to Manna Mushroom Farm in Sacramento.  The use of a hydrated lime soak is one the most cost-effective ways to produce ready-to-fruit oyster mushroom logs.  Always remember this method has been developed over time and each grower will likely need tweaks and modifications to the general concept.


Follow this link to Fungi Allly:



Also see the link on Aloha Medicinals webpage:



The basic rules to follow are:

  • use hydrated lime with a low magnesium content (minimum <2%, best less than 0.2%) this type of lime in South Africa is from Bredasdorp and is sold as “Water purification lime”.
  • soak for 16-18 hours.
  • use high quality spawn of strains known to work with the system like Elm A, HK, CA, PL  and AX strains.
  • do not make columns too wide or else they will get anaerobic in the middle (rot and smell really bad).
  • remember the goal in mushroom farming is “The Production of High Volume of Mushrooms at a Low Cost” 
  • always try and get the cellulose waste that no one knows what to do with!  ‘Waste” such as sawdust preferably not pine (working on being able to use pine sawdust), paper (newspapers, office paper etc.), residues of field crops and material from pack houses are all possibilities.


Manna Mushrooms fungi ally

Straw logs made using lime pasteurization

hydrated lime soak

Chopped straw after hydrate lime soak



Hydrated lime soak – Fungi Ally and Manna Mushroom farm visit — 14 Comments

  1. Thanks for a comprehensive article. Plz guide me in followings
    1. For pasteurization of wheat straw, how much hydrated lime for 200 liter container?

    2. Can I use fungal treated wheat straw (say at day 30-40 or with full mycellia growth) for inoculation of freshly soaked wheat straw, instead of grain spawn ? If so … What are your comments, plz.

    • Hi
      1. For 200 litres 200gram of hydrated lime should be sufficient.
      2. Yes, you are describing substrate spawn where you have sterilized the substrate and inoculated with clean tissue culture to create your spawn. Personally I prefer grain spawn as it has more inoculation points than substrate spawn will have.
      Kind regards

  2. can sterilise hardwood sawdust using calcium hydroxide. if yes, how long do i soak it and in what concentration.

  3. Pickling lime (Also known as hydrated lime / calcium hydroxide) has been associated with Botulism poisoning. Since you’re using it as a sterilization agent and not for pickling, I wonder if the risk is diminished?

    • Hi
      There is no risk of botulism in using hydrated lime as they grow in the absence of oxygen and this process is oxygenated.
      Kind regards

    • Hi
      Good question, if the right lime is used and the pH of the lime solution is above 12 then I have not seen much contamination using the lime pasteurization method.
      Kind regards

  4. I grow oyster mushrooms but i want the formula when using dehydrated lime.What quantity do i mix to a 200litre drum

  5. Im shopping for spawn, nice to find you, there seem to be more and more spawwn producers as of late or maybe they are just getting easier to find, either way i am pleased. Thanks for the info on hydrated lime.

    Just one thing…the facebook thing on the right that scrolls with the page gets in the way of me reading text on your website. It is quite anoying, please move or remove it.

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