Growing gourmet and medical mushrooms

Paul Stamets. Growing gourmet and medical mushrooms. - Ten Speed Press, 2000


1. Mushrooms, Civilization and History

2. The Role of Mushrooms in Nature

3.Selecting a Candidate for Cultivation

4. Natural Culture: Creating Mycological Landscapes

5. The Stametsian Model: Permaculture with a Mycological Twist

6. Materials fo rFormulating a Fruiting Substrate

7. Biological Efficiency: An Expression of Yield

8. Home-made vs. Commercial Spawn

9. The Mushroom Life Cycle

10. The Six Vectors of Contamination

11. Mind and Methods for Mushroom Culture

12. Culturing Mushroom Mycelium on Agar Media

13. The Stock Culture Library: A Genetic Bank of Mushroom Strains

14. Evaluating a Mushroom Strain

15. Generating Grain Spawn

16. Creating Sawdust Spawn

17. Growing Gourmet Mushrooms on Enriched Sawdust

18. Cultivating Gourmet Mushrooms on Agricultural Waste Products

19. Cropping Containers

20. Casing: A Topsoil Promoting Mushroom Formation

21. Growth Parameters for Gourmet and Medicinal Mushroom Species

Spawn Run: Colonizing the Substrate

Primordia Formation: The Initiation Strategy

Fruitbody (Mushroom) Development

The Gilled Mushrooms

The Polypore Mushrooms of the Genera Ganoderma, Grifola and Polyporus

The Lion’s Mane of the Genus Hericium

The Wood Ears of the Genus Auricularia

The Morels: Land-Fish Mushrooms of the Genus Morchella

The Morel Life Cycle

22. Maximizing the Substrate’s Potential through Species Sequencing

23. Harvesting, Storing, and Packaging the Crop for Market

24. Mushroom Recipes: Enjoying the Fruits of Your Labors

25. Cultivation problems & Their Solutions: A Troubleshoting guide


I. Description of Environment for a Mushroom Farm

II. Designing and Building A Spawn Laboratory

III. The Growing Room: An Environment for Mushroom Formation & Development

IV. Resource Directory

V. Analyses of Basic Materials Used in Substrate Preparation

VI. Data Conversion Tables





Sterilization of
Supplemented Substrates
Once the bags are filled, the supplemented
(sawdust) substrate must be heat treated for an

extended period of time before inoculations
can proceed. In a small pressure cooker, two to
three hours of sterilization at 15 psi or 250°F.
usually suffices for supplemented sawdust substrates. When sterilizing more than 100 bags in
a large pressure vessel, however, the thermody-

namics of the entire mass must be carefully
considered in choosing a successful sterilization protocol. Hundreds of bags tightly packed

in an autoclave achieve different degrees of
"sterilization." 'When bags are stacked against
one another, the entire mass heats up unevenly.
Even so, this practice is common with those
whose autoclaves must be packed to capacity
in order to meet production requirements. Bear
in mind that sawdust has high insulating prop-

erties, making heat penetration through it
Other factors affect the minimum duration

of sterilization. The substrate mixture should
be wetted just prior to filling. If water is added
to the formula and allowed to sit for more than
6 hours, legions of contaminants spur to life.
The more contaminants at make-up, the more
that are likely to survive the sterilization cycle.
Fresh hardwood sawdust needs 2-3 hours of
sterilization at 15 psi or 250°F. The same mass
of sawdust supplemented with rice bran needs

4-5 hours of sterilization. Hence, one of the
cardinal rules of mushroom culture: as the per-

centage of nitrogen-supplements increases
relative to the base substrate, the greater the
likelihood of contamination, and thus the
greater the needforfull and thorough sterilization.

I prefer the aforementioned formula using


alder sawdust, alder chips, and rice bran. An
autoclave filled tightly 5 bags high, 6 bags
wide, and 8 bags deep (240 bags) requires exposure to steam pressure for5 hours at 18 psi to
assure full sterilization. The lower, central core
is the slowest to heat up. (See Figure 136.) By

placing, heat-sensitive sterilization indicator
strips throughout the mass of sawdust filled
bags, a profile of sterilization can be outlined.
Each cultivator must learn the intricacies of
their system. Since the combination of vari-

ables is too complex to allow universal
judgments, each cultivator must fine tune his
techniques. Even the type of wood being used
can influence the duration of the sterilization
cycle. Woods of higher density, such as oak,
have greater thermal inertia per scoop than, say,

alder. Each run through the autoclave is
uniquely affected by changes in the substrate
Those with ample space in their autoclaves
separate the layers so thermal penetration is
uniform. This is ideal. The sterilization cycle
can be shortened, again best affirmed by sterilization-sensitive markers. However, few
individuals find themselves in the luxurious
position of having an autoclave capable of run-

ning several hundred bags with one or two
inches of separation between the layers of
bags. These one or two inches could be used to

increase the capacity of the run by approximately 20%. Many small scale cultivators are
soon forced to maximum capacity as their production expands with market demand. In the
long run, dense packing is generally more cost-

efficient compared to loose packing. Hence,
dense packing, although not the best method, is

usually the norm not the exception with the
small to mid-size cultivator. Thus, the manager
of the autoclave cycle operates from a precarious

decision-making position, constantly juxta-

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