It’s not a hard process to build your own laminar flow hood. You only need a few materials and some basic carpentry skills to get your hood set up. A laminar flow hood is your essential tool for scaling up your growing process effectively. Let’s get started!

What is a Laminar Flow Hood?

A laminar flow hood is a device that blows clean air across your work surface. The hood part is misleading as it does not have to contain an actually closed area. The device works by pumping air through a 0.3 Micron HEPA filter which traps microbes and spores. The air then travels across your work surface in clean flat currents. This is known as lamination or laminar flow.

Because of the way the air is flowing over your work area any outside contamination is pushed away by the air flow. This keeps contamination away from your materials as you work and allows you to do more sensitive techniques such as creating spore syringes or working with agar plates.

How to Build a Laminar Flow Hood


For this project you will need the following:

  • 1 4’x4′ sheet of 3/4″ hardwood plywood
  • 1 8′ long 1″x1″ furring strip
  • 1 8′ long 1″ edge trim
  • 1.5″ wood screws
  • 1″ nails
  • 1 roll of 3/8″ weather stripping
  • 1 tube of all-purpose silicone sealant
  • 1 400-500 cfm blower
  • 1 12″x24″x5&7/8″ HEPA filter, 0.3 microns
  • 1 power strip with a on/off switch


  1. Cut your hardwood plywood sheet into 5 pieces with the following measurements:
    -2 25.5″x16.75″ (top and bottom)
    -2 16.75″x13.5″ (sides)
    -1 24″x15.25″ (Back)
  2. Assemble your box being careful not to split the plywood. The sides will be outside of the top and bottom and the back will be outside of the box. Failing to assemble it this way will cause your HEPA filter not to fit.
  3. Measure and cut your edge trim and furring strip into 4 parts to fit inside your box.
  4. Install the edge trim and furring strips so that your HEPA filter will fit flush with the outside of the box when pushed against the strips.
  5. Measure the opening of your blower. Cut that size hole in the top of the box so that the blower’s output is between the back of the box and edge trim.
  6. Install the blower. It should come with mounting brackets or have them built in, but if it does not be sure to find mounting brackets for your specific blower size and model.
  7. Seal all joints and connection on your box using silicone sealant. Be sure to also make a small but complete seal around the blower connection as well.
  8. Slide the HEPA filter into the front of the box and tack it in with nails to ensure it does not slip out during use. It should be a reasonably snug fit. Make sure you can easily remove the nails as you will need to replace you HEPA filter on occasion.
  9. Plug in and test your laminar flow hood. Air should only come out of the front through the filter. Seal any leaks and test again.
  10. Your flow hood is ready for use!

Note: You may not be able to find the exact size air filter you need in your area. If that is the case you can adjust the dimensions of your box to fit what you have available. Be careful to make sure your filter can handle the airflow you put through it to prevent it from being ineffective.

Instructions For Use

When you are ready to use your flow hood be sure to work on a clean non-porous surface. Clean the area in front of the hood with 10:1 isopropyl alcohol and then switch on your hood. Clean anything that comes into the clean area to reduce your chance of contamination. You’re now ready to work.

To keep your flow hood in optimal condition be sure to replace your filter over time as recommended by the filter manufacturer. Avoid touching the filters surface or spraying it with chemicals to keep its integrity whole.

Start Using Your Hood

This project shows you how simple it is to make a huge improvement in your mushroom cultivation process. The hood can easily be built from scratch and requires minimal tools for construction. Be sure to measure everything twice before cutting as you want to reduce gaps in the box. Once you’re ready to go the flow hood will open up whole new possibilities for growing mushrooms at home without the fear of contamination.