The Optimal Shotgun Fruiting Chamber Temperature

Mushrooms grow where there are ideal conditions presented to them. One way to provide ideal growing conditions for mushrooms is by building them a shotgun fruiting chamber (SGFC). In building a shotgun fruiting chamber, it is required to set an ideal temperature that will allow your mushrooms to fruit.

The optimal temperature recommended in shotgun fruiting chambers is 60–65°F (15.5–18°C). The optimal temperature in mushroom fruiting chambers varies depending on the mushroom species. Although oyster mushrooms and lion’s mane mushrooms prefer temperatures of at least 60°F, shiitake mushrooms prefer cooler temperatures.

Below, we will explore more about shotgun fruiting chambers and how they can provide ideal growing conditions to allow your mushrooms to grow and flourish.

The Optimal Shotgun Fruiting Chamber Temperature is Between 60 - 65°F

The optimal temperature in mushroom fruiting chambers will vary depending on the mushroom species you’re growing. But to be safe, the optimal temperature should at least be between 60 - 65°F (15.5 - 18°C).

To give you a guide in knowing the ideal fruiting temperatures for some of the known mushrooms, we tabulated each one below:

Mushroom Species	Optimal Fruiting Temperature
Oyster mushrooms	60°F – 70°F
Button mushrooms	53°F – 60°F
King oyster mushrooms	59°F – 65°F
Shiitake mushrooms	45°F – 65°F
Maitake mushrooms	55°F – 65°F
Lion’s mane mushrooms	60°F – 75°F

From the table, you can see that oyster mushrooms, lion’s mane mushrooms, and king oysters prefer warmer temperatures at least around 60°F, while shiitake mushrooms, button mushrooms, and maitake mushrooms prefer cooler temperatures.

You can mimic these ideal fruiting temperatures in your shotgun fruiting chamber and make sure they stay in the range of whichever species you choose to grow.

Mushrooms may seem like they just pop out of nowhere, but usually, they grow in areas where favorable conditions are provided. If environmental conditions are extreme, growers usually resort to building fruiting chambers such as a shotgun fruiting chamber (SGFC).

A shotgun fruiting chamber is a makeshift mushroom terrarium made up of a good-sized clear tote that is covered in holes and filled with a few inches of perlite at the bottom.

A shotgun fruiting chamber is an excellent alternative to a terrarium. It provides the perfect balance of fresh air and humidity that mushrooms demand to produce flushes. The advantage of building a shotgun fruiting chamber is that it uses natural fresh air to signal the mushroom to grow.

The design of a shotgun fruiting chamber commands what is needed for the mushrooms to grow. The tote is required to be clear to allow indirect natural light exposure. The holes in the tote are needed to keep fresh air exchange, and the perlite serves to maintain the humidity.

Although a shotgun fruiting chamber does not require thorough checking and maintaining, some practices such as fanning and spraying can be helpful. Although the holes can keep up with their role in allowing fresh air exchange, manual fresh air fanning can be done as extra effort.

You can perform fanning by removing the lid of the tote once the blocks are placed in the chamber. Perform manual fresh air fanning at least twice a day.

Since fanning brings dry air to the chamber, the best thing to do is keep up with the humidity level of the fruiting chamber. Mist the chamber using a bottle spray and make sure to keep the inside walls and the perlite soaked in water.

Do not spray directly onto the mushroom block. Remember that overwatering can cause problems to the mycelium or fruit body as they may develop bacterial blotches and molds.

Building a Simple Shotgun Fruiting Chamber Using Clear Tote and Perlite

A shotgun fruiting chamber is an inexpensive way to provide your mushrooms with some fresh air yet keeps the humidity high. Building one is very easy and will only require you to have materials such as a plastic tote and perlite.

Perlite is a natural volcanic mineral that can hold water that evaporates over time. The evaporated water from the perlite is what keeps that humidity high inside the fruiting chamber.

The following are the specific requirements for building a simple shotgun fruiting chamber:

• A good size clear tote enough to grow your mushroom kit with some space left
• A drill with ¼” bit
• 1 - 2 gallons of coarse perlite
• Spray bottle
• Measuring tape or ruler
• Sharpie pen
• Small wood block approx. 6” x 3” inches

To start building the chamber, here are some basic steps you may follow:

1. Mark the areas where you drill the holes all over the tote

Using your measuring tape and sharpie, mark the holes on both sides of the container including the lid. Create a grid of holes spaced 2 inches apart throughout the tote. Start creating the grid 4 inches from the bottom to avoid the perlite.

2. Drill the holes using the ¼-inch bit driller

Use the wooden block to brace the tub wall so it won’t flex and crack. Drill slowly and lightly to avoid cracking the tote. When done, brush away the plastic shards and then wash and dry the bin before proceeding to the next step.

3. Fill the tote with enough perlite and moisten it

Add 2-3 inches thick of perlite at the bottom of the tote and pour distilled water over it. Make sure to pour just enough water on the perlite to avoid stagnant water which may cause mushroom growing problems. Mix evenly to let the perlite absorb the water.

4. Install the grow kits inside the shotgun fruiting chamber

Place the fruiting blocks in the fruiting chamber. You can cover the holes or uncover them depending on fresh air and humidity requirements. You can also add more holes if necessary. Mist the inner walls of the fruiting chamber and dampen the perlite every as often. You may purchase a thermo-hygrometer to keep watch of the humidity level as well as temperature.

5. Elevate your shotgun fruiting chambers

Once everything is done, you may want to elevate your shotgun fruiting chamber instead of letting it touch the surface directly. You may put blocks or jars underneath each corner of the chamber.

At least 5 cm. is good enough elevation from the surface. This will allow a balanced fresh air exchange throughout the chamber.

6. Place your fruiting chamber in an area where it can maintain ideal fruiting conditions

Lighting, airflow, and temperature are some of the factors you need to consider when deciding on the location of your fruiting chamber. The best location to place your shotgun fruiting chamber is in a space near the window which has indirect natural light and is away from the direct wind blowing.

Corner areas and areas with direct sunlight and excessively drafty space will tend to dry out your mushroom fruiting blocks so avoid these spaces.