The Use of LED Lighting in Mushroom Cultivation - Part 1
Mushroom cultivation & LED lighting
Although they are all called "mushrooms", shiitake mushroom and Grifola frondosa mushroom are biologically as different as cucumbers and tomatoes. It is therefore necessary to establish the most optimal cultivation methods for each mushroom.
The blue light (wavelength 450nm) are most effective for the cultivation of various types of mushrooms. Using Photon Grow blue LED tubes not only increases the yield of mushrooms, but also be able to cultivate products with a higher market value.
We have also developed white LED lights that take into account the working environment and the comfort of the human eye, while including blue light that promotes the growth of mushrooms. The use of these white lights in various mushroom cultivations has ensured that the same yields and other effects can be obtained as with blue LEDs. Using the white LED lights in the cultivation of various mushrooms can achieve the same yield and other effects as the blue LED lights.
The new cultivation techniques using LED lighting for the eight main mushrooms cultivated in the market (Shiitake, Enoki, Agaricus, Phyllostachys, Agaricus, Araguchi, and Bairinga) will be explained in detail in the following blog posts.
*Regarding blue LEDs – the author uses the photosynthetic photon quanta flux density (unit: μmol/m2/s) to express the intensity of LED illumination.
Increased yield of shiitake mushrooms on the fungus bed with blue lighting
The cultivation of shiitake mushrooms in a mycelium bed can be divided into two stages: the cultivation of shiitake mycelium and the growth of shiitake mushrooms. By cultivating the mycelium, the protoplasts of the shiitake mushroom are formed in the mycorrhizal bed. Light (especially blue light) is necessary for the formation of this protoplast. So we began to wonder whether the use of blue LED light during the "mycelium cultivation" phase would promote the formation of the base and increase the occurrence of mushrooms.
The cultivation phase of the shiitake mushroom can be divided into: the mycelial elongation phase, which spreads throughout the medium for about 30 days, and the subsequent maturation phase.
Firstly, the effect of blue LED irradiation during the mycelium elongation phase was tested. If the mycelium elongates faster under blue light, it is possible to shorten the "mycelium elongation phase" and thus the duration of the cultivation phase. However, it was shown that blue light slowed mycelial elongation. (Fig. 1) This means that blue LED light is not suitable for mycelial elongation.
Afterwards, the occurrence of shiitake mushrooms was investigated at the “maturation stage" under blue LED light.
The result was a maximum 50% increase in growth weight and a maximum 47% increase in the number of shiitake mushrooms growing above the M size, which has a higher market value, compared to when using fluorescent lighting at the maturation stage. (Figure 2) In this way, irradiating the beds with blue LEDs at the maturation stage has helped to increase the occurrence of shiitake mushrooms.
So, what is the most suitable brightness of blue LEDs?
The occurrence of shiitake mushrooms was tested at six different levels in the blue LED light intensity range of 1.2-20.5 μmol/m2/s. The results proved that the highest occurrence of shiitake mushrooms and the number of mushrooms above M size were found at 10.5 μmol/m2/s.
Blue LED lighting shortens the maturation phase
We already know that the use of blue LED lighting during the maturation stage leads to increased yields. This is because the blue LED irradiation of the bacterial bed promotes the formation of the protoplasts. Since it promotes the formation of protoplasts, can the maturation stage be shortened?
Shiitake mushrooms are generally divided into long-term cultivars of 100-120 days, and short-term cultivars of 80-100 days. For the long-term cultivar, after 30 days in the dark (mycelial growth phase), one group was irradiated with fluorescent light for a total of 110 days. The other group was irradiated with blue LED light for a total of 82 days. For the short-term cultivar, after 30 days in the dark (mycelial growth phase), one group was irradiated with fluorescent light for a total of 90 days. The other group was irradiated with blue LED light for a total of 70 days.
The occurrence of shiitake mushrooms in each bed was measured. It was found that beds irradiated with blue LEDs produced the same product weight as beds irradiated with fluorescent lights at a reduced cultivation time of 30-20 days, and produced more mushrooms of high market value above M size and fewer S size and deformed mushrooms. (Fig. 3/4)
The reduction of S size mushrooms also reduces the time required for packaging as packaging of the S-size takes longer. Also, the management of high temperature suppression* to prevent the production of large numbers of S-size mushrooms during the first cultivation can be omitted.
In summary, the use of blue LED lighting during the maturation phase can reduce the cultivation time by 20-30 days.
*High temperature suppression management: additional 4-7 days of high temperature incubation at 25°C-27°C at the end of the cultivation stage to reduce the number of protoplasts, followed by 15-17°C for shiitake cultivation.