Contamination Problems? Check Out The Flow Hood

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Categories : BlogMagic Mushrooms

Contamination Problems? Check Out The Flow Hood

Contamination can be a nightmare for the beginner mushroom grower, but there is a way around it – the flow hood.

When it comes to dealing with mushroom spores, working in a sterile environment is key. Without one, it is easy for the novice mushroom grower to accidently contaminate their efforts, and make the whole grow a failure.

One way to overcome this by ensuring maximum sterility through the construction of a flow hood. This is a small space that utilises a ventilator and a HEPA filter to create an area of almost perfect sterility, reducing the chances of accidently contaminating anything to almost nothing.


A HEPA filter is a type of air filter that removes up to 97% of air particles larger than 3 micros (which is extremely small). If you have a ventilator blowing through a HEPA filter then out through to a small enclosed work area, you ensure that all air where you are working is clean and free on contaminants. Plus, by blowing this sterile air over your work area, you prevent other air in the room coming your direction. The great majority of contaminants are airborne, so filtering them out really helps.


Fortunately, making a flow hood is quite easy and fairly inexpensive (depending on how technical you want to get). It is a DIY project though, so you will need a bit know how to do it.

Basically, you need to construct yourself a work station box and a top box. The work station box, as the name suggests is where you will work with mushrooms/spores, whist the top box is where your fan and filter are housed.

The work station box is basically a solidly constructed box placed on its side, so that its opening is sideways on for you to eventually work in.

The top box goes on top of the work station box. It has a small opening at its bottom, linking in with a small opening in the top of the workstation box where the HEPA filter goes. The ventilation fan is placed in the top box, connecting into the filter, then the top of this box is left open with a fine mesh to help prevent dust and other large particles from entering. You should be left with a system that takes air from the top box, filters it, and blows out into the workstation box, keeping it contaminant free.

Of course, the actual process of making it is a bit more in-depth and involving, but there are plenty detailed user made instructions available across the internet, giving a step by step guide as to how a DIY flow hood is created.

We highly recommend that anyone who is serious about growing mushrooms takes a further look into the matter, and makes their own. It can be the defining factor that eventually helps a blundering novice become a seasoned pro. Good luck!