In today’s article, I want to address the influence of your cropping or substrate container on the yield and the size of your mushroom.
Table of Contents
Type of substrate container
When it comes to the cultivation of mushrooms, many kinds of cropping containers can be used. This is especially true for small mushroom farmers. You can use bags, bottles, card boxes, trays, columns, and so on. All of them have pros and cons.
In the world of commercial mushroom cultivation, 80 % used bag cultivation, and only 4 % bottle cultivation.
92 % of the specialty mushrooms are grown in bags. But not only the professionals are mainly using bags to cultivate their mushrooms for small mushroom farmers bag cultivation is the way to go as it is (to some extent) cheaper.
To understand this preference, let’s look at table 1. The table contains several aspects of mushroom farming as well as growing conditions that are influencing the choice for either one of them.
Factors like upfront investment play a big role, especially for small mushroom farmers. Due to this fact, the degree of automation is low and replaced by manual labor. Which then increases the operating costs.
Another interesting factor is consistency. As we will see, later, the size of the cropping container influences the amount of fruiting bodies as well as the size of them. Bottle cultivation has here an advantage over the bag cultivation.
This is since the size of the bottle, as well as the mouth of the bottle, is designed with the intention to get the same results repeatedly.
|Bag cultivation||Bottle cultivation|
|Investment||Low to moderate||High|
|#of flushes||up to 4||1|
|Yield per unit||High||Low|
|Consistency of production||Moderate||High|
|Substrate quantity per unit||Moderate to high||Low|
Table 1: Comparison of the pros and cons of bag and bottle cultivation
If we look at the process flow of both cultivation methods, we find that there is (almost) no difference.
The main difference comes in the two additional steps for the bottle cultivation – scratching and sprouting. Here the mycelium at the opening of the bottle is removed so that the surface is exposed to the air (oxygen), and the fruiting is triggered.
- Preparation of substrate
- Mixing of substrate materials
- Filling into bottles or bags
- Cooling the substrate
- Spawn run (incubation)
- Scratching (only bottles)
- Sprouting (only bottles)
- Packaging and shipment
Influence of the color of the substrate container
After we have chosen the type of cropping container we want to use for the cultivation of our mushrooms, the next question which we have to address is the color of the container itself.
As the majority goes with a transparent one, many don’t question the choice. But the color of your cropping container has an impact on, for example, biological efficiency.
I found one study which compared different colors of poly bags with each other. It was found that a green poly bag produced the highest biological efficiency. While a blue poly bag resulted in the lowest biological efficiency (Fig. 1).
As with the color of the cropping container comes to some disadvantages like not seeing contamination as good as with a transparent one, the choice to use such a container is understandable.
As the biological efficiency is just a little bit smaller than the green polybag, the advantage to spot contamination early on weighs out the small loss.
Figure 1: Biological efficiency and the average yield of different spawn ratio and colors of poly bags
Effect of the size of the substrate container
Besides the type and color of your cropping container, the main factor which drives your mushroom yield is the size of the container itself.
I found two studies that addressed this topic. In the first, standardized PP bags were compared to each other. While the first two sizes (7×14″ and 6×12″) showed no significant differences in comparison with the others there is.
According to this study, the best size would be 7×14″, 6×12″ of 9×14″ (Fig. 2). Or to put it differently. The lowest yield was achieved with a bag size of 8×12″.
Figure 2: Effect of different PP bag sizes on the yield of Pleurotus ostreatus
The second study not only compared different bags but also compared them to different bottle sizes. I, therefore, found this study more appealing, because I got a better understanding of the two different cultivation methods.
In the next two figures (Fig. 3 and Fig. 4), the outcomes of this study are shown.
Figure 3 focuses on the productivity and the biological efficiency of the two different cultivation techniques.
While the larger bag (50x 30 cm) produced a higher yield per bag (2x), the biological efficiency is lower (2x) in comparison to the smaller bag. But the larger bag used 3x more substrate.
If we look at the bottle, we see that the biological efficiency of the smaller bottle is roughly the same while using 5.5x less substrate, which means, in the end, there is no difference between the two bottles when it comes to yield and biological efficiency.
Figure 3: Effect of container size on the cultivation of Pleurotus ostreatus
But there is a difference between the two bottles when it comes to the size and weight of the fruiting bodies itself (Fig. 4). The smaller bottle produced overall smaller mushrooms.
This is in stark contrast to the smaller bag. Here we see no difference in the size of the mushrooms between the two bags.
Figure 4: Effect of container size on the cultivation of Pleurotus ostreatus
To summarize the finding, we can conclude that for the bag cultivation, a smaller bag (here 25x 20 cm or 10×8″) is preferred over the larger one as the biological efficiency is higher, and there is no impact on the mushroom size itself.
When looking at bottle cultivation, we see no difference in the biological efficiency but a difference in the mushroom size. We, therefore, can adjust the bottle size to the preferences of our customers.
Impact of the area per unit volume
“The yield of mushroom depends on the surface area of the substrate bed available for fruiting bodies to appear.
For larger beds, the available area for fruiting bodies to appear per unit volume becomes smaller.”
Or, as Cotter put it, “The total volume of the substrate in the container versus the surface area that is exposed to the air is a critical factor for mushroom formation and yields.
You must find the balance: building enough substrate volume to support mushroom production, but not so much that you’re wasting substrate. In general, there is a set weight of mushrooms capable of fruiting off a given volume of the colonized substrate.”
During my research, I found an interesting study. The author calculated the area per unit volume (cm²/cm³) for each of the trails and compared the numbers with the yield (Fig. 5).
The study revealed that the optimum area per unit volume is around 0.20 cm²/cm³. This means that the exposed area is 5x smaller than the volume below the exposed area. If there is more or less volume, the yield drops.
At this ratio, an increase in the yield by 30 % was found.
Figure 5: Effect of the area per unit volume on the yield of the fruiting body
Effect of the hole size
Another factor that influences the mushroom yield is the size of the opening of the bag. Some poke holes into the bag or slice it with a knife to form, for example, an X.
The size of the hole determines the amount of substrate surface, which is prone to the air. The oxygen then triggers the formation of a pinhead and the development of the fruiting body.
Cotter writes, “A similar balance applies to the concept of exposed surface area. In an enclosed plastic container with holes punched in it, for example, the holes must be kept to a size and a number that allow for maximum mushroom production.
Not enough holes and the medium cannot breathe and will become anaerobic, creating large, dead marbled areas inside the biomass that will compromise yields.
But too many holes overstimulate the colonized substrate, signaling to the mycelium to produce more mushrooms than it can support, causing partial or complete crop failure.”
In a study, the author studied the effect of the hole size on the mushroom quality. It could be found that the hole size had a positive correlation with the mushroom yield and a negative correlation with the stipe size (Fig. 5).
Figure 5: Effect of the bucket hole size on mushroom quality of Pleurotus florida
In the same study, the author investigated, also the number of holes per bucket and found that the mushroom yield had a positive correlation with the number of holes per bucket and the stipe size a negative correlation (Fig. 6).
Figure 6: Effect of the hole number per bucket on mushroom quality of Pleurotus florida
Influence of the filter size and filter porosity
The last two factors I want to address are the influence of the filter size and the filter porosity.
The size and the porosity of the filter patch determine the amount of gas exchange taken place between the outside world and the mycelium inside the bag.
We would expect that the larger the filter, the higher the gas exchange and, therefore, the lower the CO2 level inside the bag. This effect could be demonstrated in a study that was conducted back in 1995 to investigate how much CO2 would be buildup inside the bag during the growth of a shiitake strain.
The results of this study are shown in figure 7. They were there types of filter sizes, 0.5, 1.0, and 2.0. While the bag size stayed the same (15x 20x 45 cm). As expected, the largest filter resulted in a lower CO2 level inside the bag.
As shown in figure 7, cutting the size of the filter in half doubled the amount of CO2 inside the bag.
Figure 7: Effect of filter size on buildup of carbon dioxide during incubation of shiitake strain (filter size: 0.5x = 6cm², 1.0x = 12 cm², 2.0x = 24 cm²; PP filter: solid lines, HDPE filter: dashed lines)
The impact of this CO2 concentration on biological efficiency is shown in figure 8.
Here the lowest CO2 concentration produced the highest biological efficiency (Fig. 8, CS-41).
Figure 8: Effect of filter size and material on the biological efficiency of two different shiitake strains
Another aspect of the filter size is the amount of contamination due to the filter. The results coming from the same study are shown in figure 9.
Here again, the largest filter leads to the lowest contamination rate (Fig. 9, CS-41).
But as you already noticed, there is a difference between the two strains studied during these trails. While the strain CS-41 had a positive correlation with the filter size regarding biological efficiency and contamination, the strain CS-53 had a negative one.
Figure 9: Effect of filter size and material on the incidence of contamination in two strains of shiitake
As said at the beginning of this section, the porosity will impact the biological efficiency, too. How much was studied by Shen. The author found a significant difference between a medium and a high porosity filter and no significant difference between the low and the high porosity filter (Fig. 10).
All these results lead me to the conclusion that we have to test all variables for all mushroom strains separately to get the best results for each one of them.
Which is for the majority of small mushroom farmers, nothing easy to achieve.
But as the saying goes, “slowly but steady.” Therefore, keep testing.
I hoped you enjoyed my article about the impact of cropping containers.
Now I want to hear from you:
What info in this article surprised you the most?
And are you planning to make adjustments in the future? Which one?
Let me know by leaving a quick comment.
 Yamakana 2017
 Own table based on several sources
 See Yamakana 2017
 Own figure based on Dahmardeh 2012
 Rashid 2007
 Own figure based on Owaid 2015b
 Own figure based on Owaid 2015b
 Bisaria 1989
 Cotter 2014
 Own figure based on Bisaria 1989
 Cotter 2014
 Own figure based on Okwulehie 2008
 Own figure based on Okwulehie 2008
 Donoghue 1995
 Donoghue 1995
 Donoghue 1995
 Shen 2008
 Type 14: low porosity, 0.3 to 0.5 μ pore size, <45% pores/unit square, Type 3TN: medium porosity, 0.3 to 0.5 μ pore size, > 75% pores/unit square, Type 3BN: high porosity, 1.0 to 5.0 μ pore size, > 90% pores/unit square