Cultivation of Shiitake on Sawdust

Read the Indoor Cultivation section in the Commercial Cultivation page first.

On this page we will focus on indoor sawdust block production in bags, which is the method we use to grow Oyster myshrooms at Fun Guy Farm.


The type of equipment and setup you will require depends on your geographical location and on the production sophistication level you plan to achieve. For North America and Europe labour expenses can be a large portion of the total operating budget of an operation. Investment in sophisticated machinery from Japan, although increasing startup capitol requirements will prove to be well worth the investment later on. These machines will achieve a standardization of products i.e. blocks as well as eliminating the human errors. For Asia, Africa, and South America where labour costs are lower, the investment in the more sophisticated machinery may not prove advisable. A building or structure to prepare and grow out your blocks will be required. Again depending on geographical location and the local temperature and humidity, the sophistication of the building will vary.

We will concentrate mainly on conditions necessary for North American production. There are two ways you can go with this, you can either buy ready to fruit blocks from a block supplier  and  just grow out the mushrooms, or you can do the whole process of spawn and block production yourself. In the former case you will only need grow rooms, which can consist of converted barns, industrial buildings, or simply insulated greenhouses. The latter case has two options as well, you can buy the spawn for inoculating the blocks from a spawn manufacturer, which saves you all the headaches of culture work and mushroom strain upkeep, or you  will require a laboratory for culture work.  So depending on which option you choose, your building will require the following areas:

  • Laboratory
  • Substrate preparation and storage areas
  • Sterilization area
  • Cool down and bag inoculation area.
  • Block incubation or spawn run area
  • Fruiting rooms
  • Fresh mushrooms sorting and storage area


This room will have to be very clean, practically sterile to ensure the long term viability of your operation. Training of one or more persons in sterile culture work  and spawn production is essential to be able to maintain pure  cultures and ensure uncontaminated spawn . This is where it all begins, contamination here will spread to your blocks and seriously affect the production.  Ideally the room should be practically airtight and air should be blown into it through a HEPA filter The following equipment will be necessary for your laboratory work:
  • HEPA filter workbench for  a sterile airflow
  • several pressure sterilizers for your culture media and spawn
  • agar plates, jars, shelves etc.
Substrate preparation and storage areasSawdust can be purchased in bulk from either a sawmill, or from sawdust wholesalers, the latter usually can supply it packaged in paper bags either slightly compacted or loose, for a higher price. In both cases you will have to make sure that you are getting hardwood sawdust. If you get it in bulk an outside storage area will be acceptable but it must be covered. Bags can be stored indoor in the same area as the wheat, or rice bran that you  will need as a supplement. Other supplies will include limestone and gypsum. The substrate preparation area will be where the above materials are mixed and water added and finally bagged to be sterilized. Equipment for this area will include.
  • ribbon mixer sized to your daily bag production
  • a machine to load the mixer i.e. a tractor with a front bucket or conveyor
  • a bag filling machine ( a machine that presses the mix in the bags is recommended)
  • a small conveyor belt to unload the mixer into the bag filling machine

Sterilization Area

The bags of substrate (mushroom growing media) will have to be sterilized to get rid of  competitors such as molds and bacteria. This will provide you with a clean material for your mushrooms to grow on. This is done with steam, either at low pressure for up to 18 hours in a “steam box” such as a converted 20′ shipping container, or at high pressure in an autoclave for 4-6 hours. Equipment here will be:
  • autoclave or steam box (double door unit are recommended)
  • loading carts for the bags of sawdust
  • steam boiler

Cool Down and Bag Inoculation Area

Ideally this room is directly connected to your exit door of the double door autoclave or steam room, and it is well sealed with an incoming HEPA filtered air flow. The sterilized bags should be brought down to inoculation temperature as quickly as possible (ideally 8 hrs), so a cooling unit in this area is necessary. Once cooled down the bags should be inoculated as soon as possible and must be done on a workbench in front of a HEPA filter This area is very important as this is where the spawn is introduced into the sterile media in the bags, lax procedures  here will result in unacceptable levels of  contamination (more than 3-5 %). Equipment here will include:
  • HEPA filer equipped workbenches
  • optional automatic inoculators
  • bag sealers

Block Incubation or Spawn Run Area

The inoculated bags  will require a spawn run period ranging from 2-4 months depending on your shiitake strain. At Fun Guy Farm we use a 4 month, long incubation strain, this has proven to give the best quality mushroom an the least contamination of the blocks from molds. The bags will have to be kept between 20-23C (68-75F) and 70-80% humidity throughout the four months. They should be arranged on shelves so that they do not touch and the air in the room should be exchanged often to allow the dissipation of the carbon dioxide produced by the mycelium as it takes over the substrate. The size of this area will depend on the length of your spawn run, for a four month time period multiply your weekly bags production by 16, i.e: 1000 bags per week x 16 weeks= 16000 bags. As you can see this area will have to be quite large, to be able to exercise more control it is best to have several rooms, 4 rooms or one for each month of production is recommended. Equipment here will be:
  • Air conditioning and air exchanging units
  • humidifiers
  • fans to move the air around
  • temperature and humidity controls

Fruiting Rooms

This is where payoff happens, the now solid blocs of mycelium and sawdust are removed from the plastic bags and put on shelves to allow for the mushroom s to pop out. The blocks can produce for a period of up to six months, the first 3 flushes will be the most productive, tapering off for flushes 4-6. Some people do not even bother with the last 2 if they are short on space. The environmental requirements for the blocks change somewhat from the beginning to the end of the cycle, so to be able to control these changes it is advisable to have at least 4 grow rooms so that blocks at the some stage of development are not mixed with older blocks. This is not an absolute necessity as a one grow room operation can work. Equipment for the grow rooms will include:
  • Air conditioning and heating units
  • Air exchangers (fresh air needed 3-4 times per hour)
  • humidifiers
  • humidity and temperature controls

Fresh Mushrooms Sorting and Storage Area

The fresh mushrooms need to be stored at 3-4C (35F) and will keep a couple of weeks at this temperature. They should be delivered as soon as possible however as they will also sit with the wholesaler and then the retailer. They will be sorted into the various grades and weighed and boxed or packaged. A mushroom drier my be required if there are periodic or seasonal gluts in your area, or if you have a market for dried mushrooms. Equipment required here is:
  • weighing scales
  • packaging equipment
  • drier
We can assist you on all phases of indoor cultivation. The most important phase is the initial set up. With proper consultation expensive mistakes can be avoided and will lead to higher yields as well as progressive schedule rather than one that is marred with down time to modify environments.

Contact us for more information