How To Build Your Own DIY Grow Room

Custom Building Your Indoor Grow

Indoor growingis perhaps the best way to control the environmental conditions of a plant organism. Many aspiring growers want a space to grow in, free from the hardships of pests and bad weather, prying eyes, cops, and thieves. A spot where you can play God; at least for a bit.

DIY Grow Room
The frosty buds you could be producing if you grew your cannabis at home.

It’s unfortunate that many beginners feel like building their own DIY grow room or custom space is just too expensive… both in terms of time and money. The task of an indoor grow can be daunting, from the outside.

Well, I am here to say that if you can use basic hand tools like a saw and a screwdriver, you can build your own grow space. It will be a step up from a tent, and likely cost less.

I am going to show my age a little here… but when I started growing, you weren’t able to find grow tents online. Well, “times have changed”. You can now go online and just buy a tent. A good tentcosts around $200 – for a fairly small footprint.

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End of article, right? Wrong. While I have nothing negative to say about these store-bought tents (other than cost and potential environmental impact), I feel like a space you have built on your own allows you to customise and enjoy the whole process much more.

If you feel similarly, this will be the guide for you.

Deciding On Your Grow Area

When choosing a space to grow in, I always like to pick an area that is low traffic. Basements are ideal, if you have one. Garages and sheds are also good; as are unused spare rooms. So long as the room has power. The idea is that the space you choose will only ever be disturbed by the gardener/s.

Once you have chosen an area, you need to determine how much of that area you can dedicate to a semi permanent space. I put mine in the basement – I had 4 feet (1.21m) for width, and 7 feet (2.13m) for both length and height. This is plenty of space.

The total cost on my build was about $150. It effectively amounted to a much sturdier and cheaper setup than a tent. You get a lot of space to grow in. Go look online for a tent that is 4ft x 7ft x 7ft … I’ll wait.

Customising To Your Needs

What’s your situation?

Are you trying to supplement your consumption to a point where you no longer need a dealer? Are you just trying to get enough to smoke your own occasionally? Identify this. It will help you determine the amount of space you need.

If you were using 5 gallon pails for either a DWC hydroponic system, or a soil/inert soilless mix, the 4 pails and plants will take up at least 3.5 feet x 3.5 feet(1.06m x 1.06m). That’s without accounting for spacing. Your plants will need to be spaced to grow independently from one another, and for each to get a proper amount of light. Determining a comfortable amount of space is the first step to your build.

The Complex Variables Involved In Your DIY Grow Room

The purpose of building a room is to control the conditions in which your plants will grow. Variables the gardener can control include:
  • Relative Humidity (RH) of the room – This can be accomplished by running a humidifier/dehumidifier.
  • Temperature – Cannabis plants like different temperatures depending on genetics/strain. This will be helpful to look up before you begin growing. Typically, anywhere between 20 and 28 degrees celsius will work.
  • Airflow/Cooling – To grow top notch cannabis, you’ll need to circulate the air. For most beginner grows, you can get away with some fans on the wall and a passive intake. The need for air conditioning will increase depending on how much heat your light produces. (I will go over how I accomplished this in my build, later).
  • Light – As I just touched upon, the light you choose may have an impact on your cooling situation. Your light will need to fit your budget (they’re expensive!) and desired yield. Growing indoors allows you to completely control the light cycle; in the good ol’ outdoors, you get what you get.

This list could be expanded upon to include many other variables, including pH and irrigation; but for a beginner, this is a good list to focus on.

Constructing Your Own Space

You will need some tools and materials.
That’s right: it’s time to take a trip to the hardware store.

Or rob a construction site, what do I care…. I’m not you*.

(*Friendly Aussie Buds does not advocate robbing construction sites – it really is your decision to own if you go ahead and do something illegal…)

A List of Tools, Materials and Resources for Your Grow Room

  • Circular Saw (or a table saw)
  • 10’ lengths of 2×4 – you can save money using cull lumber. You’ll need around 12-15 to build the same sized room I did.
  • 3” #8 Robertson, plywood screws. (I like these but any 3” plywood screw will work)
  • 2 1/2’” #8 Robertson, plywood screws (same with these)
  • 2″#8 Robertson, plywood screws
  • 1 sheet of ¾” plywood
  • Utility Knife
  • Tri square
  • Cordless (or corded) drill
  • # 8 Robertson drill bit
  • Staple gun
  • Staples
  • Black and white Polyethylene film (better known as Panda Poly)
    • Any reflective surface will work – such as mylar sheeting
  • Safety glasses – it’s good practice, protect your eyes!

From The Ground Up

Building your space will literally require you to start from the ground up.

First, you need to cut a piece of plywood that will fit the footprint you determined earlier. Then, you take pieces of 2 x 4 and cut a few lengths to make a frame for the base of the floor.

I made two lengths at 7 feet and 3 lengths at just under 4 feet.Subtract the width of the 2 x 4 so that they can be placed in between the 7 foot lengths. Then, take your tri square and ensure the corners are squared off, before using the 3” plywood screws to join each 3″ 2 x 4 to the 7’ 2 x 4’s (on edge, so the 4” side is vertical).

You should end up with a rectangular/square frame, with one piece of 2 x 4 in the middle for support. After this is completed, cut two more pieces of 2 x 4 to fit between the frame you just built, parallel to the 7″ boards to add strength to the floor. (See Fig 1.1).

Use the 2” plywood screws to secure the plywood sheet to the rectangular frame you have just created, placing 2” screws along the frame to secure the floor.

My reason for building a floor first is to keep the room elevated off the floor of wherever you plan to build. This prevents any possible flooding inside the space from getting to your electrical devices (ballast, plug ins, etc.). It also helps insulate the floor of the grow room, preventing the cold from conducting into your pots.

Building A Frame

Next, you will need to build a frame to attach the panda poly to.

You can accomplish this by cutting the uprights (height is determined by you – mine was 7 feet), taking the upright lengths you have just cut, and screwing them onto the outside of the corners of the floor you just built using 2.5” plywood screws.

After you have done this, add some pieces between the upright ones. Finally, add some pieces to the roof to solidify the structure (See Fig 1.2) and to hang a light from (Fig 1.3).

This can be accomplished in much the same way as you built the floor.

It will all depend on how you choose to hang your light – and if you have a light moving system – but for the basic room, you’ll just need a place to install some eyebolt screws.

Be Sure To Fix Any Light Leaks

Once the frame has been built, all you need to do is take that trusty staple gun and put the panda poly up inside of the structure you have built (See Fig 1.3). I found it easiest to take the panda poly and wrap the walls with it, then staple it down (white side in, obviously).

The goal is to prevent light leaks… which are exactly what they sound like. Light leaks are places where light will enter into your grow room from the outside. I leave the overlap that hangs onto the floor and into the roof, for extra protection. Then, I cut a piece for both the floor and roof, and staple them down.

I do this so the plastic is as tight as it can be. I use white gorilla tape to seal the seams between the sheets, and to cover any holes made from missed staples – or tears in the panda poly.

Your Finished Product

Finally, the room should look something like this when you are done (below).

If you plan to build this structure outdoors, you will need to look at building a proper roof. You’ll also need to use plywood for the walls. I cut a square hole on the left hand side and hung a scrap square piece bigger than the hole, which functioned as a passive air intake (It’s a light baffle. This works because light does not bend around corners… Physics, read a book!!!). Any ambient light that comes in is negligible.

Using a light baffle won’t affect your crop size in flower, but it may possibly cause your plants to show signs of becoming hermaphrodites.

I added a shelf to the outer left of the room (not pictured) – but it’s basically some L brackets and a spare piece of the plywoodboard I used for the floor, as a place for my ballast to sit.

I cut a hole in the lower back left corner inside the room for power – again, making a light baffle – and installed a ground fault interrupting surge bar on the outside underneath the shelf I built. Running all power cables out of the hole at the bottom left and plugging into the Surge bar, I installed the bar off the ground (again, in case of flooding). The room I have my space built in is close to a water heater.

…And there you have it! This has been how to build a grow room yourself. I hope you give it a go – I hope this guide inspires people to build their own indoor grow space. Even if a beginner got a little bit of knowledge out of this, I’d be happy.

What I built for myself was pretty basic and inexpensive, but it works so well for me. It’s a great spot to grow massive buds, free of the worries of outdoors. Everyday, it sits at the perfect humidity and temperature – and best of all, I get to grow weed in it. Not bad, hey.

A Guest Article by Jeff Vanderwood – Edited and Published by Mitch

From all at the FAB team: Thanks for writing in, Jeff!

Author: Mitch

Mitch Keys is a young writer from Brisbane, Australia unfolding in a dynamic process of becoming (like everyone else, so don’t go thinking he’s special or anything). He likes being alive.

Mitch Keys is a young writer from Brisbane, Australia unfolding in a dynamic process of becoming (like everyone else, so don’t go thinking he’s special or anything). He likes being alive.


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1 year ago

Not too sure but I reckon 200 to 280 degrees Celsius might be a tad on the warm side for cannabis??!!?? 🙂

Joe Lagrasso
1 year ago
Reply to  Will

Scorched plants! Fixed up the typo! Thanks again!

1 year ago
Reply to  Will

Learn how to read! It says 20-28 degrees

Joe Lagrasso
1 year ago
Reply to  Brendon

We corrected it after he commented 🙂


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