Mushroom Mycelium: Does Light Affect Growth?

Mushroom mycelium does not require light to grow, but it does help the fruiting process. Mycelium is usually found in the darkness underground or under logs, branches, or nestled between trees and rocks. Once the mycelium has grown and multiplied in the dark, exposure to light triggers the fruiting process. The amount of light needed varies depending on the species of mushroom. For example, oyster mushrooms require diffused light to initiate fruiting, while button mushrooms grow in darkness or under very low light.

Mycelium doesn't need light to grow, but it helps the fruiting process

Mycelium does not require light to grow. In nature, mycelium grows underground in darkness. It is a fungus that feeds by decomposing organic matter, and therefore does not rely on light as an energy source.

However, light is important for the fruiting process. Once the mycelium has grown and multiplied in the darkness, exposure to light triggers the transformation into hyphal knots, which then develop into pinheads (baby mushrooms) and eventually mature into full mushrooms. This process can be replicated artificially by exposing the mycelium to light once it has grown to around 60-75% of its desired size.

The amount and type of light required for fruiting vary across different species of mushrooms. Oyster mushrooms, for example, require diffused light to initiate fruiting, with an intensity of 500 to 1000 lux for 12 hours per day. In contrast, button mushrooms thrive in darkness or under very low light, as intense light can inhibit fruiting. Shiitake mushrooms also require moderate light, as too much light can cause burns or defects on the mushroom caps.

When growing mushrooms artificially, it is important to consider the light intensity and heat to avoid overheating or burn damage. Indirect sunlight or artificial light can be used, with LED or CFL lights being popular choices. It is generally recommended to keep the lighting conditions similar to the natural environment of the mushrooms, with minimal light hours, as too much light can increase the risk of contamination.

Blue and white LED lights can increase commercial yields of oyster mushrooms

While mycelium does not require light to grow, light is necessary to complete the fruiting process and guide the growing direction of the fruiting body. The oyster mushroom, or Pleurotus ostreatus, is one such species that requires light to develop mature fruiting bodies.

Oyster mushrooms occur naturally in a variety of habitats and climate zones, and their caps are of industrial importance. To increase the proportion of caps, the oyster mushroom is typically grown in limited light conditions. However, studies have shown that blue and white LED lights can increase commercial yields of oyster mushrooms.

In one study, oyster mushrooms were exposed to different colors of light, including fluorescent light, blue LED, red LED, and green LED, after mycelia growth. The blue LED treatment resulted in the maximum yield and the lowest substrate utilization efficiency. The white oyster mushroom obtained a significantly greater amount of total fresh weight, higher biological efficiency, and a greater number of fruiting bodies.

Another study exposed oyster mushroom primordia to blue-light, red-light, and dark conditions for 7 days. The results showed that blue light enhanced the growth and development of the stipe, pileus, and gill of the oyster mushroom.

Overall, blue and white LED lights can increase commercial yields of oyster mushrooms by increasing the number of fruiting bodies, enhancing growth and development, and improving the quality of the mushroom fruiting bodies.

Light intensity and heat should be considered when choosing grow lights

Mushrooms are known for growing in shady forest spots, but they do need light. Mycelium, the fluffy white substance that precedes the growth of mushrooms, does not need light to grow. However, once the pinning process begins, and mycelium transforms into clumps that will eventually become fruiting bodies, light becomes essential.

The amount of light needed varies depending on the mushroom species. Some mushrooms, such as Psilocybe Albino, require minimal light, while others, like Psilocybe Cubensis, thrive in bright light.

Light intensity and heat are crucial factors to consider when choosing grow lights. Blue and white LED lights have been shown to increase commercial yields of oyster mushrooms compared to fluorescent lights. However, placing lights too close to the mycelium can cause overheating or burn damage, preventing fruiting bodies from sprouting. Lamps with more than 7000 Kelvin of light intensity can harm mushrooms if exposed for long periods. Therefore, it is recommended to limit the number of light hours to 4-5 hours if using high-intensity lamps.

To regulate temperature, growers can use heating pads, cooling fans, air conditioners, or water-cooling systems. Maintaining a consistent temperature is crucial, as even small fluctuations can impact growth rate and quality. The ideal temperature range for most mushrooms is between 65-75 °F (22-24 °C), though some sources state that the optimal temperature is 76 °F (25 °C).

Mushrooms incubate in darkness or very low light

When cultivating mycelium, it is important to consider how mushrooms grow in nature. They are often found on the forest floor, nestled between trees and rocks or under logs and branches. They colonize in darkness until they reach 75% colonization, after which they can be exposed to light to help them fruit. This light comes in the form of the sun peeking through a tree canopy or reflecting off a small body of water.

During the incubation phase, light is generally not necessary for most fungal species. This phase focuses on creating optimal temperature and humidity conditions for the species being cultivated. Darkness allows moisture to be retained and used to assist the metabolizing process.

Some growers use LED or CFL lights on 12-hour schedules, while others rely on indirect sunlight from a window. Light intensity and heat should be considered when choosing a grow light, and blue and white LED lights have been shown to produce higher commercial yields.

Different mushroom species have specific light needs

While mycelium may not need light to grow, mushroom fruiting bodies do. The amount of light required varies across different mushroom species. For instance, the psychedelic cubensis require plenty of light to grow healthy, mature fruiting bodies, whereas the opposite is true for button mushrooms (Agaricus bisporus), which grow mainly in darkness or under very low light. Intense light can even inhibit the fruiting of these mushrooms.

Shiitake (Lentinula edodes) mushrooms also require moderate light to initiate fruiting, but too much light can cause burns or defects on the mushroom caps. In the pop corning and browning phase, low light can even have a positive impact. For the rest of the growth process, darkness is preferable.

Oyster mushrooms (Pleurotus spp.) generally require diffused light to initiate fruiting. An intensity of 500 to 1000 lux for 12 hours per day is often recommended. Blue light, in particular, has been shown to promote faster colonisation times and a higher yield of fruiting bodies in some species. This is because blue light mimics the natural conditions under which many mushrooms grow. In the wild, mushrooms are often exposed to the blue light present in daylight, which signals to the mushrooms that they are near the surface, triggering them to begin fruiting.

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