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Category: DIY equipment & Teks

How I built my first Laminar Flow Hood for home mycology for $99.86

written by @PsychonautJim

Make your own cheap and simple laminar flow hood for home mycology
Complete guide on DIY laminar flow hood for mushroom growing at home

Cheap and simple DIY Laminar Flow Hood setup for mushroom growing at home

Hey Shroomers!

I am @PsychonautJim, member of Shroomok Growers Community on Discord.

I grew mushrooms for a short time nearly 20 years ago. I had a good experience back then with great flushes. After recently listening to a podcast featuring Paul Stamets, I went down a rabbit hole of information about all the positive benefits of microdosing.

This reinvigorated my interest in growing mushrooms and I was also reminded of how much fun mycology is. I almost have as much fun growing mushrooms as I do eating them!

I promised Shroomok to share my experience and details on how I built my very first laminar flow hood for my amateur mycology hobby. Now I finally have a pleasure to fulfil my promise.

Let's get started!

What is laminar flow hood

Laminar flow hood — a fan-powered HEPA-filtered device that produces a laminar flow of air that moves across the workspace allowing for open sterile work without the hassle and inconvenience of a still air box (SAB) or glove box. The air input goes through the HEPA filter and particles less that 0.3 microns in size are filtered out and the sterile air is pushed across the work plane. Flow hood is usually used for manipulations, that require high sterility level: inoculation, working with agar, transfers etc. Mushroom cultivation glossary

Why I decided to make a laminar flow hood

I wanted to use a flow hood as opposed to a still air box (SAB) or glove box, because of how cumbersome dealing within the confines of a SAB can be.

On the other hand, I’m building my tek on a budget and have space constraints to consider; and typically flow hoods are expensive and bulky.

So, I began a search to MacGyver my way to a sterile environment.

List of stuff for DIY laminar flow hood

My total costs for current setup: $99.86*

*Prices listed are at time of purchase. Current prices may vary

🔶 1. Lasko FF305 Air Flex 2-in-1, 20-inch Box Fan and Air Purifier in one with MERV10 Air Purifying Filter for Cleaner Air and a Cooling Breeze ($59.99). I bought it on Amazon:

Air Flex 20” Box Fan and Air Purifier in One $69.99

Fan and air purifier for DIY laminar flow hood. Laminar flow hood guide
Fan with air purifier for DIY laminar flow hood

🔶 2. L brackets with screws. I bought on Amazon ($8.99):

L Brackets 5" x 3" with screws, 4 Pack $8.89


🔶 3. Two air filters Filtrete 20x20x1, MPR 1500 filtration level. I bought them for $30.88 in Walmart, also available on amazon

Filtrete 20x20x1, MPR 1500 filtration level, 2 Filters $35.62

Filtrete 20x20x1, MPR 1900 filtration level, 2 Filters $45.94


🔶 4. Some additional tools for assembling components: drill and marker

Drill Set Bundle with Ryobi 18V ONE+ Drill Driver

Prepare all tools and components
Prepare all tools and components for setup

That's it, we are ready for assembling!

How to assemble laminar flow hood

⚙️ 1. Prepare all required components are listed above (fan, filters, L brackets, screws) and some additional tools for setup (drill, marker)

⚙️ 2. Lay the fan flat and place the filter on top to get right measurements for the L Bracket placement. Mark the holes to drill with a marker

Mark the holes to drill with a marker

⚙️ 3. Drill holes. Ensure to use a drill bit size that fits with the screws being used to attach the L Brackets

Drill holes in a fan frame

⚙️ 4. Attach the L Brackets using the screws

Attach the L brackets

⚙️ 5. Ideally have one L Bracket on each side toward the top facing inward, along with two evenly spaced L Brackets on the bottom facing upward (4 pieces in total)

Attach L bracket on each side

⚙️ 6. Now you have additional slot for air filter

Four L brackets on each side create a slot for air filter

⚙️ 7. Slide the filter on the backside in the pre-made filter slot

Slide the filter on the backside in the pre-made filter slot

⚙️ 8. Slide another one in the slot you’ve created as well

Slide the filter in the slot you’ve created

❗️Ensure you face the filters the correct direction!

⚙️ 9. Turn fan on and kill stop contaminant monsters! Now you are ready for your mycological journey 😉

DIY laminar flow hood in action
My DIY laminar flow hood in action

How my laminar flow hood works

The idea is that doubling down by using two air filters with a high Microparticle Performance Rating (MPR) we will closely mimic the mechanisms of a flow hood. Basically, by working in front of the fan we ought to be blowing away unwanted particulates and spores, thus creating a more sterile work environment free of contamination.

My laminar flow hood in action. How I use it for inoculation, working with agar, transfer

Here I forgot about the stand to raise my petri dishes a little bit higher from the table, in front of laminar flow

Pros and cons for this setup


👍 Low cost

👍 Easy assembly

👍 Easy storage, compact, mobile

👍 Open air sterile work, more convenient than SAB or glove box

👍 Has successfully worked in my testing


🔴 Potentially not as effective as a professional and more expensive setup for laminar flow hood. Although it works great for my home mycology

Possible upgrades for this flow hood setup

Maybe I'd like to add another unit to direct clean air from two different angles

Write it up!

Hope my experience will be helpful and this simple device bring more opportunities for your mycological experiments.

Feel free to ask any questions regarding my flow hood in comments to this post or in 🔧diy-growing-set-up channel on Shroomok Discord

Enjoy your home mycology and have a happy growing!

Made with love by @PsychonautJim 🍄

Promoted by ©Shroomok


This is what i've been using for months and it works amazingly well. I cannot tell you how much of a game changer it was vs driving myself crazy doing things in a SAB. Tip for using this type of device: turn off all airflow in your workspace and run a HEPA filter in the room for an hour or so before starting your work. I've left agar plates open for an hour in front of this with no contamination. Ive done agar to agar, grain to grain, liquid culture to grain, lc from bottle to syringes, and more with this setup and had zero contamination. If you're starting out, this thing is your magic bullet seriously.


Curious; the filters aren't HEPA filter-rated.... surprised these have enough filtration

Also; you do get decent laminar flow from these? I guess since you don't have any contam issues it must be fine. Did you use the filter that comes with the fan at all?


Found a higher rated filter that might work better; maybe it's overkill but it does have a higher MERV rating


Found a better filter; MERV 16 (HEPA's are rated at MERV 17) - this one has the same form factors as the ones you posted too, including thickness

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