What Is a Still Air Box (SAB) & How to Use One for Mushroom Growing

When you’re working with mushroom cultures, grain jars, or agar plates, the biggest enemy is contamination. Mold spores, bacteria, and dust are floating around in the air, ready to land on your project and ruin it. A Still Air Box (SAB) is the simplest and cheapest way to create a controlled workspace for mycology — no fancy lab needed.

In this guide, we’ll cover what a still air box is, how to make one, and exactly how to use it to cut contamination risk while working with mushroom cultures.

What Is a Still Air Box?

A Still Air Box is a clear plastic container with two arm holes, designed to give you a semi-sterile workspace. The idea is simple:

• You place your tools and materials inside.

• Close the lid and let the air inside settle (no drafts).

• Then work slowly, so contaminants in the air don’t swirl onto your project.

It doesn’t filter the air like a laminar flow hood. Instead, it relies on still air — less movement = fewer chances for spores and bacteria to land.

Why Use a Still Air Box?

• Lower contamination risk when doing agar work, inoculating grain jars, or transferring cultures.

• Cheap and easy — just a clear tote with holes.

• Portable — unlike a flow hood, you can move it around and store it.

• Beginner-friendly — perfect for home mycologists who don’t want to spend hundreds of dollars on lab gear.

How to Make a Still Air Box

The DIY version is cheap and takes less than an hour.

Materials:

• 1 clear plastic storage tote (60–100 quarts is a good size).

• A hole saw, heated can, or knife to cut arm holes.

• Sandpaper or tape to smooth edges.

Steps:

1. Choose a tote that’s tall enough to fit jars, agar plates, and your hands comfortably.

2. Cut two holes (about 5–6 inches wide) in the front, at a comfortable arm level.

3. Smooth the edges so you don’t scratch your arms.

4. Wipe it down with alcohol, and you’re done.

💡 Pro tip: Don’t make the holes too big — smaller holes = less airflow disturbance.

Buying a Still Air Box

If you don’t want to DIY, you can also buy a pre-made SAB online. Some even come with gloves attached, though most growers prefer simple open arm holes.

👉 Check this still air box on Amazon

How to Use a Still Air Box

Here’s the step-by-step process I (and most growers) use:

1. Prep your materials. Have everything clean and ready before you start (jars, plates, scalpel, alcohol wipes).

2. Load the SAB. Place everything inside, close the lid, and wait 2–5 minutes. This allows the air inside to settle so particles aren’t floating around.

3. Sanitize. Spray the inside walls with isopropyl alcohol (70%) to help trap dust and spores.

4. Work slowly. Move your arms and tools gently. Fast movements stir up air and increase contamination risk.

5. Keep it simple. Only put in what you need — the more clutter, the harder it is to stay sterile.

Tips for Best Results

• Always wipe down jars and tools with alcohol before placing them inside.

• Wear gloves and sanitize your hands.

• Flame-sterilize scalpels or needles outside the SAB, then reintroduce them slowly.

• Don’t talk, cough, or breathe heavily toward the box — air movement = contamination.

• Practice patience — stillness is your best friend in a SAB.

SAB vs Flow Hood

A laminar flow hood blows filtered air across your work surface, giving you true lab-level sterility. But it costs hundreds of dollars.

A SAB isn’t perfect, but for most home growers, it’s more than enough. If you work carefully, you can get consistently clean cultures with just a plastic tote.

Final Thoughts

A Still Air Box is one of the simplest but most important tools for mushroom growing. For under $30, you can set up a workspace that dramatically reduces contamination and keeps your projects clean.

👉 Want more beginner-friendly mushroom growing tips? Check out my Mushroom Recipe Book or my SHTF Survival Mushroom Guide for deeper techniques and strategies.