Soy Hull Pellets

WHY GROW MUSHROOMS ON SOY HULLS?

So what are soy hulls and why are they so effective?

Oyster mushrooms are known to grow on just about anything… coffee grounds, sawdust, banana leaves, cotton seed hulls, and many other agricultural waste products… they all make reasonable substrates.

But some substrates are bound to produce faster growth and higher yields, and I gotta say that for Oysters, I have never seen something so effective in producing huge yields as the Master’s Mix.

Soy Hulls are just the exterior skin of Soy Beans, and are essentially a waste product of soybean farming.

For whatever reason, these soy hulls – when mixed with sawdust – have just the right nutritional composition for explosive fruiting, huge yields, and nice big fruits. It also seems to produce large and dense clusters, with endless folds of oyster mushrooms just clamoring all over each other to burst out of the bag.

You can play around with different ratios but most growers note that a 50-50 mix is ideal. Any more than 50% Soy Hulls, and your mix will be too nutritionally dense, and you will have a higher risk of contamination, or deformed mushrooms. Using less than 50% will diminish expected yield due to insufficient nutrition.

PELLETIZED SOY HULLS

Unless you live in a rural area and have direct access to a soy farm, you are most likely to find soy hulls in pelletized form, commonly sold as a nutritional supplement in horse feed. I can’t confirm what the horses think, but I can tell you that mushrooms sure love them!

Pelletized Soy Hulls are relatively cheap, and should be easy to find at any agricultural feed store. You might even be able to find them online.

These rock-hard pellets are not as easy to break up as hardwood fuel pellets- which naturally break apart as soon as you add water- so you are best off to soak them in water overnight, which makes them easy to mix with sawdust.

The soy is quite sticky and gooey, so be prepared to make a bit of a mess.

MAKING SOY HULL FRUITING BLOCKS

Using the recipe described above, follow these steps to grow mushrooms on soy hulls with awesome results every time:

STEP 1: SOAK THE SOY HULLS

Soak the hulls in the appropriate amount of water, which is about 700ml for every 2.5 cups of pelletized hulls. It’s best to soak the hulls overnight so that they get a chance to break up. You can also use boiling water which will allow the soy hulls to break up a lot faster, although you’ll still need to loosen them up with your fingers if you want to use them right away.

STEP 2: HYDRATE THE FUEL PELLETS

Add 700ml of water to the fuel pellets until they are evenly broken up. Using hot water can speed this process up significantly. If you use cold water, just use your fingers to break up all the pellets into a nice even sawdust.

STEP 3: MIX AND STERILIZE

Mix the hydrated soy pellets and hardwood sawdust thoroughly and pack into a large autoclavable mushroom grow bag. Fold over the top of the bag and pressure sterilize at 15PSI for 2.5 hours. I am sure that you can get away with a shorter sterilization time, but I have not experimented with this too much. I like to play it safe, and 2.5 hours will be sure to kill whatever contamination might be lurking in your substrate.

Read more about growing with soy hulls and masters mix here: https://learn.freshcap.com/growing/growing-mushrooms-on-soy-hulls-the-masters-mix/