To Supplement my Grow Blocks or Not
One of the big discussions I also see is if it is worth it to supplement your blocks or not? I find that it comes down to personal preference and what you’re trying to achieve. Supplementing your Grow blocks with any nutritional material serves only two purposes:
1. Increases rate of microbial growth.
2. Increases first harvest weight.
Two common materials used to supplement hardwood growing blocks are
1. Wheat Bran
2. Soy Hull
The max amount of supplementation one should do is a 1 : 1 ratio of Hardwood to Supplementation. The next question to decide is which kind of nutrient supplementation should I use for my Mushrooms? For that we should take a look at the nutrient profile of the two, as shown in Table 1.
Table 1. Nutrient Table
Protein
The thing to note about Protein is it’s made of Polypeptides, which are in turn made of Amino Acids and composed of NH3 (Ammonia). This is important because mushroom mycelium require a good source of Nitrogen to grow which they acquire from breaking down protein. It is good to note Soy Hulls also contain urease, which is an enzyme used to breakdown Urea (Amonia) into Nitrogen. Having urease present gives the opportunity for the mycelium to focus producing other enzymes, one reason why Soy Hull seems to produce far better initial flushes.
Fiber
Another essential component for proper mycelium growth is Fiber, Fiber consists of cellulose, lignin, and hemicellulose. Think of fiber as a storage source of energy, mycelium needs to digest fiber into simple sugars, note that hemicellulose contains mixed-linkage glucan which mycelium will break down into β-Glucans. Fiber is a crucial in proper mycelium development as they will also use it to build hyphae and fruiting bodies. Fiber is the main source of food and energy for mycelium.
Sugar
Next, is sugar level. Soy Hulls have 3x more sugar that the mycelium can directly digest and utilize to grow. My theory behind why Soy Hulls only provide a great first flush is due to the mycelium going into “Shock” or “Withdrawal” from the sugar high.
Net Energy (Calories)
The last thing to take a look at is the Net Energy level or calorific value, this can give us a quick understanding of the amount of available “energy density” that will help provide mushroom growth. The bigger the number the more dense and better conversion you’ll see in your fruiting blocks.
By comparing the above Table 1, we can see when supplementing with wheat bran offers the best nutrient supplementation and long term growth as it contains more Protein (Takes longer to digest).
We now have two good options to of nutrient supplementation:
1. Wheat Bran- Provides multiple uniform harvests (Long term growth), great for home growing and portions.
2. Soy Hull - Big First Harvest, great for commercially growing.
There we have it, scientifically breaking down what nutrient supplementation will provide. You can also play around with these levels to figure out the perfect balance that will work for you.