There are some species of mushrooms that will benefit from using straw or manure as a bulk substrate to maximize fruiting potential. If you would like to grow Portabellas, all of the Oyster mushrooms, Shaggy Manes, the Paddy Straw mushroom, or the King Stropharia mushroom you should use your colonized substrates as spawn to inoculate straw and/or manure. The bulk substrate only needs to be pasteurized to be used.

Spawning to Straw

Preparing the straw part I:

First you will need to chop your straw into 1-4" pieces. If you need straw it will be available in our substrate section. Straw only needs to be pasteurized for use as a bulk substrate. Load your straw into a pot and fill with water.

You will need to place something heavy on the straw to keep it submerged. You will also need a probe thermometer. Insert the thermometer into the middle of the straw layer. Pasteurization occurs between 150-180 degrees. You want to leave it submerged for 1 hour between these temperatures. While your straw is being pasteurized you can prepare your colonized substrate to be ready when the time comes.

Preparing the substrate:

If you are using grain spawn you can break up the contents by slamming the jar against a tire or using your hand. If you are using half-pint substrate you will need to remove it from the jar and put it into a Ziploc bag. Using your hands, carefully crumble the cake from the outside of the bag. Be careful in this step or the bag will rip. If it rips, transfer to a new one. Once the cake is in smaller sections, while keeping the bag closed, break up the cake from the outside of the bag. Try to break the cake into pieces the size of Whopper candies. Prepare all of your substrate and set these aside while you wait for your straw to finish pasteurizing.

Preparing the straw part II:

After one hour has passed in the desired temperature range for pasteurization, we will need the straw to cool. Clean out your sink with Lysol and put the drain catcher in. Wash your hands with anti-bacterial soap. Carefully empty the pot with the straw into the sink and let it cool to about 90 degrees.

Now we are going to mix our spawn with the newly pasteurized straw. Alternate between a layer of straw and a layer of substrate and mix it well. You don't want any straw pieces sticking up. Just spread the mixture of colonized substrate and straw across the bottom of a grow chamber. You will need to place your grow chamber in a dark, warm place so that the substrate can colonize the straw. This should take approximately 2 weeks.

Open your bag of casing soil and spread it evenly over your straw layer. Try to pour to a depth of about 1/2" to 3/4". After the casing layer has been applied, put the grow chamber back into a dark, warm place for about 4-5 days. After this time, relocate your grow chamber to a zone in your house where the temperature is 70-80 degrees. The drop in temperature triggers pinning. You will also need to expose the casing layer to light for at least 12 hours daily.

Spawning to dehydrated manure

You will need:

8 x 4 x 18" 2 Mil Gusseted Poly Bags (These are not autoclavable)

A 5 gallon bucket or large tray

Dehydrated manure or compost

Probe Thermometer

Large Pot

Hydrating the Manure:

Load your large tray with dehydrated manure or compost. Whatever you are processing. Soak the substrate down with a garden hose and mix it around thoroughly. When full saturation has been reached and water begins pooling in the bottom mix it around some more and stop adding water.

Load your Gusseted Poly Bags 2/3 full.

Important:

When you load the manure by hand, gently squeeze each handful. You want the substrate to be moist not soaking and dripping. When squeezed gently, only a few drops will come out of the substrate.

EXAMPLE: Submerge a household sponge in water & fully saturate it.

Remove the fully saturated sponge. And, give it a gentle squeeze. WATER POURS OUT IN A STREAM, RIGHT. You do not want a substrate THAT WET.

Continue to slowly squeeze the sponge (very gently), until;

ONLY, A FEW DROPS ARE STILL DRIPPING OUT OF IT.

That is the same saturation point, you want a SUBSTRATE AT.

(close to 68/72% moisture capacity)

Now, its time to pasteurize the bag, or multiple bags. Seal the bags with a rubber band or twist tie but allow it to remain loose so steam can escape.

Using a large pot, fill with water until it's about 1/2 full. The pot should be large enough to allow the bag to set in. Submerse the bag/s but keep the neck above the water to keep out excess moisture. Buoyancy will cause the bag to float so you can use something to weigh it down. Be vigilant about keeping the neck above the water.

Insert a probe thermometer through the neck and into the substrate.

Heat the stove and pot until the internal bag temperature is between 160-170F. When it has reached this temperature, set a timer for 60 to 90 min. and monitor the temperature so that it remains in the 160-170F window.

When the time is up, remove the bag and allow to cool overnight.

Follow the same procedure for mixing spawn with your pasteurized substrate.

Feel free to use this article for your website but please leave the document intact, including the link section. If you use our article, send us an email with a link to your site. We might just add your site to our links page!