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Still Air Box: Purpose, Effectiveness & How To Use Correctly

Still Air Box: Purpose, Effectiveness & How To Use Correctly

If you are raising mushrooms, it is crucial to create a well-insulated setting for their development, as well as for any other cultures that may be needed.

This insulation covers every intruder that could pose a threat or interfere with the mushrooms, such as airborne pathogens, or even disturb them, such as moving air. What you need is a still air box.

What is a still air box? A still air box, or SAB for short, is a closed box with a clear window that has two armholes to allow you to handle the mushrooms inside without contaminating them with unwanted fungal spores, bacteria, or viruses. The air inside the box is still and sterile enough for the mushrooms to grow and thrive.

Naturally, a still air box requires careful handling; otherwise, what you keep inside might get contaminated. Read more to learn about the still air box and how to use it effectively.

Still Air Box Purpose

The main purpose of the still air box is to create a semi-sterile environment for the type of culture work you do.

Many people use them to grow mushrooms where the still air box maintains the purity of the mushroom fungus and prevents other fungal spores from contaminating it.

However, it can also be used for other culture work, be it for scientific purposes or for hobbies.

Is a Still Air Box Necessary?

If you want to grow a certain type of mushroom or cultivate a certain fungus, then a still air box is crucial for the success of your work or experiment.

Fungal spores are airborne and can contaminate the culture or even damage it.

The same applies to viruses, bacteria, and other pathogens that are either in the air or could contaminate the culture with physical contact. To prevent all of that, you need a still air box.

Are Still Air Boxes Effective?

As far as contamination is concerned, a still air box is quite effective in preventing intruders from getting into the box.

It is also very effective in keeping the air still and preventing air movement inside of the box even when you handle the culture through the armholes.

As for sterility, the environment inside of the box is semi-sterile at best. There’s a chance some pathogens are already present inside of the box before you introduce the culture.

Are Still Air Boxes Sterile?

Still air boxes are not 100% sterile. They do a good job of preventing intruders from getting into the box, but the environment inside of the box is semi-sterile.

During the handling, transportation, or setting up of the box, there’s a good chance that some microbes would find their way inside the box.

You might also have a contaminated culture to begin with, so you shouldn’t rely on the sterility of the environment too much.

Still Air Box Benefits

The still air box has many benefits for mushroom growers as well as those dabbling into amateur scientific experiences or who have a fascination with algae and fungi.

These benefits include the following:

  • Still Air: This is the most obvious benefit of having an enclosed box. Mushrooms and other cultures are sensitive to moving air that could impact their growth. The box keeps the air inside still and calm.
  • Sterility: The environment inside of the still air box is semi-sterile. Once you introduce the culture you’re growing and close the box, no intruders will get in as long as it remains closed.
  • Convenience: The still air box has two armholes to allow you to reach inside without having to open the box or expose the mushrooms to any intruders.

Still Air Box Size

The size of the still air box depends on the type of mushrooms or cultures you’re growing. For example, button mushrooms only need a 12”x12” square box. Larger mushrooms need larger boxes.

Still Air Box Design

The still air box has a simple design. It’s usually a square or rectangular box with a clear window and two armholes to let you handle the mushrooms without contaminating them.

The box is airtight to create a semi-sterile environment and prevent air movements inside.

Still Air Box vs. Glove Box

When it comes to growing mushrooms, you have two options. You can grow them in a still air box or a glove box. While a glove box is convenient, it’s not as sterile as the still air box.

Furthermore, the gloves can get in the way, be cumbersome, and might even create a vacuum that forces air and airborne microbes from the outside. 

Should You Add Gloves to a Still Air Box?

Gloves, for the most part, are unwieldy accessories that can compromise the integrity of the culture you’re growing.

They can suck air into the box which creates air movement and lets intruders into the box, so it’s often not a good idea to add gloves to a still air box.

Still Air Box vs. Flow Hood

If insulation is paramount in your experience or cultivation, you might consider using a flow hood rather than a still air box. Studies show that a flow hood has less contamination than the still air box.

While the air in still air boxes is still and calm, the flow hood has an uninterrupted sterile airflow that eliminates any pathogens or fungal spores and maintains the integrity of the culture.

Still Air Box Inoculation

In order to sterilize your still air box and keep the environment free of contaminants, you need to spray it with 70% Isopropyl alcohol.

Allow the alcohol to dry, or you can use a clean and sterile towel to wipe it dry. 

Can You Use a Still Air Box as a Fruiting Chamber?

You can use a still air box as a fruiting chamber. However, such work would contaminate the still air box.

If you want to use the box later for culture growing, you’ll need to clean it thoroughly and sterilize it with alcohol.

Where To Buy a Still Air Box

The best place to find a still air box is online. You might find it in the gardening section of the supermarket as well.

Bella Bora Still Air Box Mycology

This still air box measures 3x2x2 feet and can accommodate a large culture of mushrooms, agar, or mycology with the necessary supplies.

It’s also a good and viable alternative to glove boxes, flow hoods, and fume hoods. It comes with a mushroom growing kit that includes a sterilized grain bag and liquid culture.

The Bella Bora box is easy to set up and dismantle within minutes without the need for any tools.

Mushyluv Mini Still Air Box

This mini still air box measures 19″ wide x 15″ deep x 11.5″ tall and has a capacity of 32 quarts. The airtight box has a neoprene seal that keeps the lid shut and prevents contaminants from entering the box.

The box comes with arm ports with gloves pre-installed for convenience.

The package also includes additional three pairs of spare gloves and a tool tray to hold inoculation loops, Agar punches, Exacto knives, spore syringes, and other growing tools and supplies.

How To Use a Still Air Box

When using the still air box for the first time, you need to make sure it’s sterile. You’ll need bleach, 70% Isopropyl alcohol, latex gloves, paper towels, and plastic sheeting. Then follow these steps.

  1. Mix an ounce of bleach into 2 quarts of water, dip the paper towel in it, and let it soak in the solution.
  2. Spray the inside of the still air box with the alcohol, and allow it time to dry, or you can wipe it dry with a paper towel. 
  3. Spray the lid of the box the same way to sterilize it.
  4. With the gloves on, fish out the wet towel soaking up the bleach solution. Wring it tightly to squeeze as much moisture out as possible.
  5. Spread the damp towel over the inside of the closing lid. Make sure there are no wrinkles or bumps.
  6. Turn the box upside down and place it on top of the lid with the towel inside.
  7. Lock the lid onto the box.
  8. Cut the plastic sheets to fit the armholes on the box.
  9. Spray the plastic sheets with the alcohol, and let them dry.
  10. Place the plastic sheets over the armholes and tape them to the box. 

How To Make a Still Air Box

To make a still air box, you will need a clear plastic container with a lid. Choose the right size for the mushrooms you’ll grow. Anything with a capacity between 80 to 110 quarts will do.

You’ll also need a Sharpie marker, sandpaper, a metal can about 4 inches wide in diameter to make the armholes, and a heat source such as a stovetop or a butane torch. Then follow these steps.

  1. Turn the plastic container upside down on a table. Sit at the table and place your forearms on the plastic container.
  2. Use the Sharpie to mark the armhole around where each forearm meets the end of the container.
  3. Heat the bottom of the metal can on the stovetop until it turns red.
  4. Place the bottom of the hot can on the marks you made on the plastic container. The can will melt through the plastic and create a hole. 
  5. Make the other hole in the same way.
  6. Allow the holes to cool down, and then sand the edges with the sandpaper.
  7. Now your still air box is ready to set up.

Still Air Box Alternative

Although still air boxes are cheap and can be made at home with little cost, some people prefer other alternatives. A flow hood, for example, provides more sterility than a still air box.

However, the flow hood is quite costly both in upfront costs and operational costs.

A more cost-effective option is the glove box. It has gloves installed in the armholes to let you handle the mushrooms without contaminating them.


A still air box creates an enclosed and semi-sterile environment for growing mushrooms and other fungi. You can make one at home from materials that cost next to nothing.

Before you use the still air box, you need to sterilize it with 70% Isopropyl alcohol.