Do Mushrooms Need Sunlight? (My Best Take)

There is much debate surrounding whether or not mushrooms require sunlight to grow.

The fact of the matter is, though, mushrooms aren’t classified as a plant. They are instead saprophytes, meaning they get their energy from dead or decaying organic matter.

So, do mushrooms need sunlight?

Well, mushrooms do not need the sun’s rays to photosynthesize. Additionally, they don’t even have chlorophyll or roots like normal plants. However, there is a point where they need some kind of light to begin their fruiting process. Even the dimmest amount of light for just a few hours per day through a tree canopy is sufficient to begin this process.

Thankfully, we have compiled an easy-to-understand article after relentless detailed research on this topic. This aims to assist our readers who may have concerns about growing mushrooms in sunlight.

Let’s dive in, shall we?

Do mushrooms need sunlight

Do mushrooms grow better in light or dark?

Generally speaking, mushrooms need almost complete darkness to spawn. Once they spawn, they again prefer a consistently dark environment to grow to the point where they begin to fruit.

Occasional amounts of light won’t affect their growth, but it can make them take slightly longer to grow to full size.

Do mushrooms grow better in light or dark

Once it’s time to begin fruiting, light can be added to the growing environment for only 2-3 hours per day. If the mushrooms are grown indoors, some easily accessible indirect sunlight or a fluorescent lamp is sufficient.

Mushrooms prefer dark and cool environments that are also slightly humid. Some great locations for indoor growing are under a sink or in a basement. 

Do mushrooms need sunlight to grow?

Mushrooms do not need sunlight to grow from the point of spawn to just before fruiting. This is practically their whole lifespan except at the end. Then again, they can grow under extremely small amounts of sunlight, only much slower.

Do mushrooms need sunlight to grow

Their ideal growing location is on forest floors, sheltered under branches or nestled between small crevices of the rock, wood, etc. They can even spawn from dead trees.

They can use the surrounding dead or decaying organic matter, including plants and leaves, as an energy source to grow.

Sunlight doesn’t kill mushrooms; it just won’t allow them to grow to their full potential in as short an amount of time as possible. Mushroom grow houses are usually dim, cool and slightly humid. 

How many hours of light do mushrooms need?

Unfortunately, there is no universal amount of time required under sunlight by a growing mushroom. Light is only required when the growing mushrooms have reached 75% of their colonization rate.

This is the point where light should be introduced to encourage fruiting.

Every mushroom species requires a different amount of light during its fruiting phase. Some growers use LED or CFL lights on a 12 hr on/12 hr off schedule.

Some species get adequate indirect light from sitting on a window sill. Some species don’t require any sunlight at all. 

Why Do Some Mushrooms Need Light To Grow?

All mushrooms need sunlight to not so much grow but instead produce fruit. Or, in the terminology of a mushroom, they produce actual mushrooms. A fully grown mushroom will drop small spores everywhere around itself.

Why Do Some Mushrooms Need Light To Grow

Then the life cycle of a mushroom begins again as a teeny tiny drop spore. Over time, the spores become hyphae. As 2 hyphae meet, they form what is known as mycelium. The mycelium turns into a hyphal knot, then a pinhead (baby mushroom).

Lastly, they are what we know as fully-formed mushrooms. It’s at the point of a hyphal knot where just a few hours of indirect sunlight will assist with the fruiting process until it reaches full maturity. Even the dimmest of light is sufficient enough to help with the process.

List of Mushrooms That Grow in Sunlight

Not all species of mushrooms require absolute darkness to grow and fruit. Some can thrive quite well out in the middle of an open field or a place with a similar environment.

Here are 3 of the most common species of mushrooms that can grow from spore to mushroom in full sunlight.

Coprinus Comatus (Shaggy Ink Cap, Lawyer’s Wig, Shaggy Mane)

This common mushroom or fungus is usually found in the open on open roads, as a lawn covering and in some waste-type areas.

Coprinus has the uncanny ability to turn black and dissolve to the point where it disappears soon after being picked.

This species of mushroom are grown en masse in China as a delicacy that consumers know must eat once served to avoid further decay. 

Agaricus bisporus (White button mushroom)

Agaricus bisporus

The white button mushroom is cultivated in over 70 countries due to its ease of growth. They can be found wild, mostly in Europe, Northern America and Australia.

They are the species most commonly supplied to supermarkets and consumed daily.

These mushrooms are generally brown and white in color and range from 10-15 cm at full maturity.

Stropharia Rugosoannulata (Wine Cap Stropharia, Garden Giant, Burgundy Mushroom, King Stropharia)

Stropharia Rugosoannulata

The Stropharia Rugosoannulata was only discovered in Columbia in 2018. It has since been noted as growing during the late summer and early autumn in Northern America and Europe.

These mushrooms can grow an astonishing 20cm high and 30cm wide, much larger than most edible variants.

It has an asparagus-like texture and tastes like mild potato cooked in red wine. 

How does sunlight affect mushroom growth?

Sunlight is like the cherry on top when it comes to growing mushrooms. They can grow from small dropped spores to mycelium/hyphal knots without sunlight. At this point,, though,t just a few hours of indirect sunlight help produce fruit or what we know as shaping the mushrooms.

Some factors that may determine the speed of fruiting include the distance to the light source. Although mushrooms need very minimal light to fruit, the fruiting process may take longer if the light source takes longer to reach the mushroom.

The mushrooms can also be hidden under branches or nestled between logs, and the light source may only hit that spot during certain times of the day. The speed of fruiting may also be affected by light availability altogether. For example, a dark, cloudy day may restrict the light and not allow fruiting to proceed. 

Why Do Some Mushrooms Prefer The Dark?

Most mushrooms prefer darkness as that is what the requirement environment must be for them to grow effectively. Dark, dingy, damp conditions are optimal with a slight amount of humidity. They mainly prefer this darkness because they grow from spores instead of seeds.

Why Do Some Mushrooms Prefer The Dark

Spores require moisture to replicate. When moisture sits stagnant in darkness, it cannot be dried up, leaving the conditions optimal for the spores to continue to grow and reproduce.

Humidity allows the mushrooms to form fully without any hiccups. It keeps them moist and won’t allow them to crack, discolor, or stall growth. Humidity also prevents moisture from drying out.

Other Growing Condition for Mushroom

There are 2 phases of growing a mushroom. They are colonization and fruiting. 

The required growing conditions for colonization include:

  • Growing Medium – Slightly acidic, contains no other organism to compete with and adequate moisture. Generally dead or decaying organic matter. 
  • Optimal Temperature – Different species require varying temperatures. Higher temperatures can speed up colonization but encourage contamination. Colder temperatures slow down colonization but are slightly safer. Oyster mushrooms thrive in temperatures between 68-75°F (20 – 24°C)
  • Adequate Air – Proper air circulation in the growing area and growing medium is optimal. Mushrooms need to breathe to grow. As they consume their energy, they produce heat that slowly warms their growing area. To keep them cool, adequate airflow is essential.
  • Light or lack thereof – Mushrooms colonizing don’t require any light; it can even hinder their growth rate. Spores prefer the darkness to reproduce and grow. 

The required growing conditions for fruiting include:

  • Indirect Light – A few hours of day of indirect sunlight or artificial light encourages fruiting. This is essential in the latter stages of growth. Mainly once 75% of colonization is complete. 
  • High Humidity – Humidity assists with shaping and forming the fruiting mushrooms. It keeps them from forming cracks, discoloring and drying out.
  • Optimal Temperature – Fruiting mushrooms should usually be presented with temperatures around the 50-77°F (10-25°C) range. It’s worth regulating these temperatures to ensure that this stage can be completed in the shortest possible time. 
  • Adequate Air – Mushrooms are grown in the wild with consistent airflow. It’s only natural that they would require similar conditions when grown domestically. Usually, cutting holes in the growing bags will assist with this condition. The mycelium will understand that it now has space to grow once the airflow is present. Therefore it will continue with its part of the growing cycle. 

Frequently Asked Questions (fAQs)

Do mushroom kits need light?

Mushroom kits should never be placed in any light, direct or indirect. The light can cause a mushroom kit to dry out or overheat. This can result in killing everything inside prematurely. The kit will then be unusable.

Why is my mycelium not fruiting?

A mycelium may not fruit due to a few different circumstances. These can include inadequate temperature, light intensity, low humidity and lack of moisture. The mycelium needs these to be perfect for continuing its growth cycle towards fruiting. 
Lowering the temperature and increasing oxygen can help to encourage the formation of mushrooms.

Does mycelium grow faster in the dark?

Mycelium grows much faster in the dark. All growth stages before mycelium prefer darkness as it allows moisture and humidity to stay at a consistent range. It won’t allow the moisture and humidity to dry out as light does. After the mycelium begins to form as a mushroom, it should be subject to at least a few hours of indirect sunlight per day to encourage fruiting.

Can you grow mushrooms in the shade?

Mushrooms need darkness to grow in their initial stage, so the mushrooms will grow as long as the shade doesn’t allow any light. Once they reach mycelium and beyond, they need small amounts of indirect sunlight to fruit effectively.


As we have just discovered, mushrooms don’t need sunlight to grow during their initial stages. They do, however, need some source of light to finish them off as they grow into what we know as ‘fruit’ or mushroom form.

We hope that this article has helped to answer any questions related to mushrooms requiring sunlight and when it is necessary during their growth cycle. Thanks for tuning in, and as always, happy growing!

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