Hazel woodchips as substrate for mushrooms – Shiitake trial

Last year I was awarded a small grant through the Minnesota Department of  Agriculture (MDA) Sustainable Agriculture Demonstration Grant program.  The premise of my project is to evaluate coppice wood from hybrid hazel production to see if and/or how well it is suited for use as substrate for mushroom production.  If the growth of these 2 mushroom species on hazel wood is as good (or not-quite-so-good but economically better) as on the standard substrates, then hazel growers will have an outlet for their periodic plethora of hazel biomass in a manner that generates a reasonably high value item to improve their bottom line.  The spent substrate is great compost/soil ammendment, too. The two mushroom species I am testing are shiitake and winecaps.  The first is high inputs high reward, the second is lower inputs and lower rewards.  

With the shiitake, I am comparing hazel chips mixed with oak sawdust and wheat bran (1) with oak shavings/oak sawdust/wheat bran in bag culture (not log culture) (2).

In outdoor beds, I am comparing hazel chips topped with straw (1) with boxelder chips topped with straw (2) and total straw beds in the culture of winecap mushrooms (= report forthcoming later this season).

Here’s what we (myself and Ken Heidlebaugh) have been learning this winter/spring.

Preparation of Clean Room (February):

Clean room built of 2″x 3″ lumber and covered with greenhouse plastic.

Ken hanging door on clean room for access.


Double filter “blower box” to provide stream of laminar flow filtered air outward to create clean space for opening sterile bags to add mushroom spawn. (Being assembled and sealed).

Sacks of media components awaiting use.


Week 1: 3/3/17

Q. Will 3.5 hours of pressure cooking at 17-21 p.s.i. suffice to sterilize the media? Indicator strips that change color/darkness when sterilization conditions are met are imbedded into the center of the substrate in the bags.

A. Yes, but one bag popped.


Bags in pressure canner with bag on left having hole blown in it.

Indicator strip showing what it looks like when sterilization conditions have been achieved. If not, no “OK’ appears.

Week 2: 3/9/17

Q1. Will 3.25 hours suffice to sterilize media completely?
A1. Yes.
Q2. How long after removal from canner does interior of media reach temperature where spawn can be introduced without heat injury – 100F?
A2. 4 Hours… and we have another holey bag. Argggh!


Interior at 160F fresh from canner. Yes, sterilized.

Temperature at 100F 4 hours later. I was pretty blurry, too.

Week 3: 3/15/17
Q1. Will 3.0 hours suffice to sterilize media completely?
A1. Yes.
Q2. Will slow release of pressure keep the bags intact?
A2. Yes, 15 second release then wait for 2 minutes and repeat resulted in two intact bags. Yeah!!!!!!


Week 4: 3/22/17
Q1. If we follow same protocol will bags stay intact again? Is it repeatable?
A1. No. Drat! Time to order new bags, me thinks.


Week 6: 4/6/17

Q1. Can we keep the new bags intact? 

A1. On first run of the day – yes!!!! Second run 0/2. 🙁


Week 9: 4/27/17

Q1.  If we don’t expedite pressure release will the bags stay intact?  A1. YES!!!! 2 for 2 on BOTH runs!!!

Q2. What is the appropriate volume of ingredients to use to end up with the right weight for each bag?

A2. Least waste so far is with 4 (dry) qts of saw dust, 2 qts of either oak shavings or hazel fines, plus 1 cup bran and 2 scant quarts of water. 

Also showing progress in grow-out of bags inoculated 4/6/17.  The Hazel is more completely covered with hyphae, but with a single bag = could also be incomplete mixing, etc. (=very preliminary)

The first of two sets of intact bags inoculated and ready for future data and harvest!

Bag with hazel chips in medium about completely colonized on surface by shiitake mycelia.

The oak bag from 4/6 with a corner still uncolonized by mycelia. Could be slower growth OR could be less thoroughly mixed??? Future reps should help determine which of these is the case.