6 Reasons why you should use supplements | mushroom farming

In today’s article, I want to talk about 6 reasons why you should supplement your substrate and if properly done what the results are.

Why should I use supplements for my mushroom substrate?

#1: Supplementation influences the growth of the mushrooms

The first reason why you should use a supplement for your substrate is that it will reduce the time to harvest, which means you will have more production per season and, therefore, more money.

When it comes to growth, we have to look on the one side on the mycelium growth rate and, on the other hand, on the fruiting body development.

Let’s take a look at figure 1. In this figure, the mycelium growth rate of Pleurotus eryngii was tested with different supplements. The main source was wheat straw, which got supplemented with either rice bran (RB), corn stalk (CS), millet straw (M), soybean straw (S), bean straw (B), or cotton stalk (P).

The results are speaking for themselves. The red line indicates the threshold established by the control (W: wheat straw). Everything above this line grows slower, and everything below grows faster than the control group as the measurement is in days.

If we look at the overall change, it is around +16 % over the control. Ranging from -11 % up to +40 %. This means the most supplements will slow down the mycelium growth rate for this particular mushroom species.

Figure 1: Effect of supplementation of wheat straw with different supplements on the mycelium running of Pleurotus eryngii[1]

Now let’s take a look at the next figure (2). In it, we can see the effect of supplementation of sawdust with different supplements (here wheat bran, rice bran, maize powder, and a mixture of the three).

The first thing which pops out is the influence of maize powder on the number of days to harvest. Which is with roughly 135 days 20 days longer than if you would use rice bran.

If you think in terms of production cycles per year with an NDTH of 135 days, you will get only 2.7 of them. But at 120 days, you will end up with full 3 cycles per year.

Speaking of the rice bran. By using it, we can reduce the NDTH from 121 days further down to 115 days.

Figure 2: Effect of supplementation of sawdust with different supplements on the number of days to harvest (NDTH) of Lentinula edodes[2]

#2: Supplementation influences how many Fruiting bodies are produced

The second reason for using supplements is to adjust the number of fruiting bodies. The idea here is to get an even overall size of each mushroom.

Using the same substrate from before, we can see in figure 3 the effect of the supplements used on the number of fruiting bodies.

Here the maize powder produced the fewest numbers (14) while wheat bran resulted in a total of 23. If we factor in the yield (graph not shown), then we can calculate the weight of each fruiting body. For this test, the yield was 120 grams for wheat bran and 94 grams for maize powder. Those numbers lead to a weight per fruiting body of 5.2 grams for wheat bran and 6.7 grams for maize powder.

Figure 3: Effect of supplementation of sawdust with different supplements on the number of fruiting bodies of Lentinula edodes[3]

#3: Supplementation impacts the number of flushes

The third reason to use supplements is their impact on the yield per flush throughout the harvesting period.

This effect can be seen in figure 4. In this test, several mixtures were tested, and the biological yield per flush measured. As shown for all mixtures, the first flush resulted in the highest yield, which is surely nothing new to you.

But depending on the supplement, the yield for the second flush could be increased.

The best result was the mixture of 30 ZMS, which is a mixture of 60 percent of sawdust and 30 percent of Zea mays stalk. Besides, all substrates contained 9 % of rice bran and 1 % of CaCO₃.

Figure 4: Effect of supplementation of sawdust with different supplements on the biological efficiency per flush of Auricularia polytricha[4]

#4: Supplementation will influence the harvest period

The next and fourth reason why you should use supplements is, to some extent, unusually, but it goes hand in hand with the growth rate.

The harvest period is defined as the time until the last harvest. This means the longer it takes, the longer the space is occupied and can’t be used for a fresh substrate.

In figure 5, we can see the impact of different supplements on the harvesting period. The red line again is the threshold defined by the control group. Everything above takes longer, everything below less.

As we can clearly see, almost all supplements are leading to a more extended harvesting period.

Now comes the point where you have to take a pause and make a decision.

Do you want to have a higher yield and accept a more extended harvesting period, or do you want to have less yield but a shorter harvesting period? Which leads us to the next question.

How much more money are you making through the higher yield in comparison to the shorter harvesting period?

What is your trade-off?

Effect of supplementation of wheat straw with different supplements on the harvesting period of Pleurotus eryngii

Figure 5: Effect of supplementation of wheat straw with different supplements on the harvesting period[5] of Pleurotus eryngii[6]

#5: Supplementation influences the mushroom yield

Speaking of yield, it’s the fifth reason why many are using supplements in the first place.

Choosing the right supplement for your mushroom can increase the yield dramatically, as shown in the following two figures.

In the first figure (6), sawdust was supplemented with either wheat bran, rice bran, maize powder, or a mixture of the three. As the results showed, supplementing with wheat bran increased to yield by 26 % to 50 % in comparison with the other supplements.

Figure 6: Effect of supplementation of sawdust with different supplements on the yield of Lentinula edodes[7]

In the next figure (7), wheat straw was supplemented with different supplements (rice bran (RB), corn stalk (CS), millet straw (M), soybean straw (S), bean straw (B) or cotton stalk (P)). The red line indicates the threshold established by the control group.

Everything over this threshold indicates a higher yield in comparison to the control. Everything below (not the case) shows a lower yield.

The overall increase through supplementation was 48 % ranging from 22 % (soybean straw) to 78 % (maize powder + 10 % rice bran).

Figure 7: Effect of supplementation of wheat straw with different supplements on the yield of Pleurotus eryngii[8]

#6: Supplementation has an impact on the mushroom quality

The sixth reason why you should consider supplementation is the quality of your mushrooms. A shorter harvesting period or a high yield doesn’t help you if the quality of your mushrooms is below the expectations of your customer.

One factor of quality is the size of your mushrooms, as shown in figure 8. Here the substrate (sugarcane bagasse) was supplemented with rice bran (0 to 30 %) or sugarcane molasses (0 to 60 g/kg). Then the impact on the mushroom size for the individual flushes was investigated.

The researchers found that

the first flush produced first a lower yield and mainly mushrooms with a size of more than 7 cm (17.8 in).
the first flush produced no yield when supplemented with 30 % rice bran.
the first flush produced more deformed mushrooms (avg. 18 %).
the second produced for mushrooms around 50 % for the class > 7 cm and 5 to 7 cm.
the distribution for the second and third flush is evener.
the third flush is even more leveled over all classes.
rice bran and molasse are leading to similar results concerning the distribution.

Figure 8: Effect of supplementation on the quality of Lentinula edodes[9]

Influence of the C/N ratio

The first thing that most people think when asking about supplementation is the C/N ratio. And while this is an essential factor, there are many more supplements out there that can improve the quality of your mushroom and the yield.

This brings us to the first question.

What types of supplements for mushroom substrates are there?

During my research, I found the following five supplements, which provide the best value to your mushroom.

Macro-Nutrient
Micro-Nutrient
Lightning
Bacteria
Fungi

In the next five sections, I will give you a brief overview of each one of them.

Macro-Nutrient

What is the best C/N ratio?

As said, the first thing people come to mind is the C/N ratio. As many of you already know, different mushroom species need a different C/N ratio, as shown in table 1.

While mushrooms of the Agaricus species prefer a lower ratio of mushrooms (19/1) of the Pleurotus species prefer as ratio more in the mid-range (45-55/1).

Examples of C/N ratio being desirable to obtain highest yield in different species of mushrooms

Table 1: Examples of C/N ratio being desirable to obtain the highest yield in different species of mushrooms[10]

While the C/N ratio is important, I found an example where the C/N ratio had a negative correlation with the biological efficiency, actually. On the other side, but both macro-nutrients carbon and nitrogen have a positive one (Fig. 9).

I think this speaks for itself. While each of the two is important, the ratio has to be balanced to provide value.

Figure 9: Correlation between the B.E. (%) of Auricularia polytricha and C/N ratio, carbon content (%) and nitrogen content (%)[11]

How different nitrogen and carbons sources impact the growth an the yield of a mushroom can be seen in the following video. In it I talk about the influence of wheat bean, rice bran and soybean powder on the growth of oyster mushrooms.

Influence of HC/C/L ratio

While many are only focusing on the C/N ratio, I think they miss an important thing. What do I mean by that?

Carbon and nitrogen are the sources for our mushrooms. Still, they are only available as cellulose, hemicellulose, and lignin to the fungi. Which means to get to the carbon and nitrogen they have first to be digested.

And here comes the thing. Every mushroom prefers a slightly different composition. Some prefer more cellulose others more lignin.

If you, therefore, think only in terms of the C/N ratio and feed your Oyster mushrooms (Pleurotus spp.) with lots and lots of cellulose, they will grow slower and don’t produces that much yield as they could if you would feed them what they prefer.

The next figure, 10, illustrates what I mean. In this figure, we see the correlation between the mycelium run rate and the three substrates component hemicellulose, cellulose, and lignin.

As you can see, Pleurotus ostreatus prefers lignin, as indicated by a positive correlation. On the contrary, if you would have too much hemicellulose, the mycelium run rate of Pleurotus ostreatus would slow down as both have a negative relationship.

Figure 10: Correlation between hemicellulose, cellulose, and lignin on the mycelium run rate [mm/day] of Pleurotus ostreatus[12]

Another example is Auricularia polytricha (Fig. 11). Here the mushroom neither prefers hemicellulose nor lignin but cellulose. If you would provide this mushroom primarily lignin, the biological efficiency will decline.

Figure 11: Correlation between the B.E. (%) of Auricularia polytricha and the hemicellulose, cellulose and lignin content[13]

I think you get my point. Don’t only focus on the C/N ratio. It is important, yes, but I think the HC/C/L ratio is more important as it gives the mushrooms what they want.

Macro-Nutrient: P, K, Mg

Besides the two macronutrients carbon and nitrogen, there are three more macro-nutrients, which are also crucial for the mushrooms – phosphorus, potassium, and manganese. They, too, have an impact on the quality and the yield of your mushrooms (Fig. 12).

All three of them will reduce the time to colonize the substrate fully. They will as well increase the cap diameter and the stipe thickness, as indicated in the figure by the positive correlation factor. The last two will then lead to a higher weight (yield).

On the other side, the three macro-nutrients will reduce the number of fruiting bodies per substrate, and they will affect the length of the stipe as there is a negative correlation with these two characteristics.

Figure 12: Effect of phosphorus, potassium and magnesium on the quality of Pleurotus ostreatus[14]

Micro-Nutrient: Fe, Zn, Mn

Besides the five macro-nutrients, there are several micro-nutrients which are important for the growth of your mushroom.

Three of them are iron, zinc, and manganese. How they affect your mushroom is shown in figure 13. A lag of them will lead to overall lower quality as they have a positive correlation with the most mushroom characteristics.

The “only” negative correlation is the number of fruiting bodies, stipe length, and the harvesting period for iron and zinc.

Figure 13: Effect of iron, zinc, and manganese on the quality of Pleurotus ostreatus [15]

Lightning

I guess you are right now wondering why I put light on the list of supplements and thinking that you should skip this section but hold on for just a little and give me the change to convince you otherwise.

It is indeed a big question if mushrooms need light. I even wrote a whole article about it. In it, I address the point that some mushrooms don’t need light at all to grow, but some need light.

If the need light, then we can start asking the question of what kind of light is the best for which mushroom species?

To do so, I started researching and found that, for example, the growth rate and the yield can be influenced by choosing the right light by a factor of 2.

If you want to read more about How light will impact your mushroom yield, then just follow the link. In this article, I investigate the influence of blue, red, green, and yellow light on the mycelium growth rate, the yield as well as the quality of the mushroom itself.

Bacteria

Next on, our list of supplements is bacteria.

Bacteria play an essential role when it comes to growing mushrooms, especially if you are growing Agaricus bisporus, better known as button mushrooms.

Bacteria came into play during the composting process. There composition change over time (for more information about composting, see my article How your substrate will influence your mushroom yield.

How exactly they provide help to the mushrooms is not yet fully understood, but we know from experiments that they can increase the yield by 20 % (Fig. 14).

Plant growth promoting rhizobacteria affect button mushroom yield

Figure 14: Plant growth-promoting rhizobacteria affecting button mushroom yield[16]

Fungi

Besides bacteria, there is also a change during composting within the microfungal cosmos. Studies have shown the importance of these fungi to improve the mycelium growth rate and the yield of Agaricus bisporus (Fig. 15 and Fig. 16).

Choosing the right fungi can result in an increased growth rate of the mycelium by 26 % (Fig. 15) and an increase in yield by 95 % (Fig. 16).

Figure 15: Effect of different thermophilic fungi on the mycelium growth rate of Agaricus bisporus[17]

Figure 16: Effect of different thermophilic fungi on the yield of Agaricus bisporus[18]

Summary

Supplementing your substrate helps you not only to achieve a higher yield, but it influences the growth, harvesting period, number of fruiting bodies, flushes, and the quality of your mushrooms as well.

Therefore, choosing the right supplement and the amount of that supplement is an important task for every mushroom farmer out there.

But not only the supplements will impact your mushroom yield, but the same is also true the substrate itself. You can only improve a low-quality substrate with supplementation to a certain degree. You should choose the right one and improve it even further with supplementation. If you want to learn more about this topic, I wrote an article about it.

How Substrate Influences your Mushroom Yield

Besides substrate, an excellent way to supplement your mushrooms is to choose the right lighting. While many are only focusing on the value lux, it is way more. If you want to learn more about how the light will impact your mushroom yield than you can find more information in my article How light will impact your mushroom yield