Laminar Flow Hood

Last Update: 7/19/2022

Ryan's laminar flow hood

What is a Laminar Flow Hood

Mushroom cultivation requires sterile work environments for several key procedures. Basically lets assume you have a specific mushroom producing fungus culture and you want to grow it. To accomplish that you will feed it some kind of nutritious substrate. If that substrate becomes contaminated by some other type of bacterium or fungus the contamination may outcompete the desired fungus and you'll just be left with moldy sawdust and no mushrooms.

There are two major solutions to creating a sterile work environment that hobbyists use. The first and most common is the still air box. Simply a box with armholes cut in it. I used one of these for a couple of years. They work great. The only problem is that working inside a box can feel a bit cramped. The alternative, the laminar flow hood, is not nearly as simple.

A laminar flow hood is basically an air purifier with the knob turned up to 11. It works by continuously flowing clean filtered air into your work area. So what's this laminar business about? A laminar flow is essentially the inverse of a turbulent flow. In the figure bellow '(a)' illustrates a laminar flow while '(b)' illustrates a turbulent flow. The air must flow in a straight line to avoid drawing in contaminates from the unfiltered surrounding air.

a diagram illustrating the difference between laminar and turbulent flow

Laminar flow hood is perhaps a bit of a misnomer as there is no hood. laminar flow cabinet may be more apt. There are designs (more often used in professional lab settings) that employ a design more similar to a fume hood with the clean air flowing from top to bottom rather than horizontally.

On the off chance you want to build one, check out this guide from Freshcap.

An animated GIF showing the mushroom art backlit by rgb lights

Did it need RBG?

No, but does it ever really hurt. I used the lazer cutter at my local maker space to cut out some cool mushroom art and back lit it using my ESP8266 RGB project.