Grow mushrooms the EZ way.

How To Make A Cheap Laminar Flow Hood

In this post, I am going to discuss a DIY laminar flow hood (its not quite laminar flow but it works!) which I created which is both cheap and portable. In my opinion, this the perfect creation for people who are interested in getting into agar work and small amounts of grain work but don't enjoy using a still air box, don't get me wrong still air boxes are useful but sometimes it is too bulky an operation when I just want to do simple agar work. If you are looking for a portable still air box it may be worth checking out this build.

Since creating this “flow hood” I have been able to do agar transfers at my computer desk (which is filthy) with a very low contamination rate so before I hear the famous words “that won't work” which is parroted on most forums, trust me, it works.

Below I have attached a photo of the contraption, the airflow is generated by a high powered computer fan which pushes air through a H14 vacuum cleaner HEPA filter. The box is sterilized with alcohol before use and the fan is switched on to create a sterile flow through the filter; my hands can pass freely in and out of the box to place in agar plates and make transfers between plates or into jars (much like a SAB).

Full Specifications


  • Small Laminar Flow Hood Full build – Check out this small laminar flow hood which has just become available on Amazon here (UK link here). It's a very similar build, however this one has been built professionally. The diagrams may give you ideas for your own build if it is outside of your price range.

How To Assemble?

Step 1 – Using a heated knife I cut a hole in the box which would fit my HEPA filter (14 x 13 cm).

Step 2 – Push the Filter inside the hole to create a tight fit then seal the edges using the sealant and wait for it to set.

How To Use The Flow Hood?

Step 1 – Set the box on the edge of a table which you are using and tape it down using regular tape (this is important or the fan will move you box during work.

Step 2 – Place the PC fan as close to the HEPA filter as possible and ensure it is on full power to create airflow. Ensure the fan has something holding it in place which allows the fan to work (I use a keyboard) Check the airflow using a lighter.

Step 3 – Leave the fan running and sterilize the inside of the box using alcohol.

Step 4 – Begin agar work, ensure everything going into the box has been wiped down.

How Often Do You Get Contamination?

To be honest, I have done plenty of agar work so far inside this device and I have only had contamination twice and this was when I was making a liquid culture both times I suspect I was to blame for the contamination (from knocking the lids, etc).

What Are The Advantages/Disadvantages Of This Build?


  • Portable – I can use this in any room of the house with a table/plug. It is also very easy to pack away.
  • Cost – For me, this was less than 50$ to build.
  • Easy to Clean – just a quick wipe-down of the surface before use, this uses minimal amounts of alcohol.


  • Size – although the size is also an advantage, it also means only agar and small amounts of grain work can be performed inside, for 10+ jar inoculations I would probably use my SAB.
  • Limited hand movement – I prefer the movement I get using this compared to a SAB, but it could easily be a disadvantage for some people as the space you are moving in is quite small.

Could This Be a Still Air Box Alternative?

Possibly, it is a good alternative to the still air box for doing a small amount of work such as agar transfers OR cloning OR inoculating master grain jars. I definitely use this device more than my SAB but I still have a SAB for larger-scale inoculation and G2G. I look at this creation like a portable still air box which I could take to someone else's house to show them how to do agar transfers or something. If you dont have a lot of room in your house and you are only doing small scale work it could definitely be a still air box alternative.

Do You Have Any Evidence Of This Working?

Sure, I have attached pictures to this blog post of completed agar work and I also have a youtube video here which shows the flow hood in use.