Grow Box Guide: How to Build A Grow Box


Build Grow Box
Here is an example of a Grow Box made out of a dresser. It is very easy to do because the frame of the grow chamber is already made.

So you want to start an indoor garden but don’t know how to build a grow box.  Building a grow box is actually simple once you understand the mechanics.  Today you will learn every thing you need to know to build your own grow box.

The following guide will walk you through the basics of constructing a grow box out of an old piece of furniture.  A lot of indoor gardeners are also very enthusiastic about recycling, so this should really hit home for a lot of you.  The dresser grow box could be considered a grow cabinet, whatever you want to call it, the function is the same.

5 Reasons You Need Grow Box Plans:

1. Grow Room Ventilation: There is too much to say here.  You will obviously need some sort of exhaust.  The size of fan you need depends on the size of your grow box or grow room.  This simple grow box uses PC fans which can be wired to an old PC power supply very easily.  You can also control the timing of the fans by putting the power supply on a timer.

WARNING: Do not use the biggest power supply you can find.  Stick to a smaller power supply with low wattage because the fans use very little power.  If you do not know what you are doing, use a pre-made fan that you can just plug in.  For 20 bucks you can get a dryer type ventilation fan that can be attached to ducting.

Grow Room Ventilation
Cut a hole in the back of your box and screw your fan into place. You can also use epoxy or strong glue.

2. Reflective: Reflectiveness should depend on your budget.  Aluminum foil is probably the cheapest material, but it certainly doesn’t reflect the most light.  Since you will likely be using small grow lights, you will want to get the most out of it.  White poly or Mylar are the premium choice.

3. Water proof/Bug proof/Mold proof: Water proofing is one of the most important things about building a grow box.  All hydroponic systems should be in water proofed grow boxes, or outdoors where they can’t possibly make a mess.  I’ll discuss bug proof more in the next point.  Mold proofing takes a little common sense.  Don’t use carpet for the floor of your grow box or anything dumb like that.

4.  Air tight: You will want your grow box to be air tight so that light doesn’t escape, bugs will have a harder time getting in, and you will want control of the ventilation.

5. Odor control: Some people enjoy having fresh herbs, vegetables, and fruits growing in their house, but don’t want their house to smell like a garden or green house.  Some people just don’t like that smell.  You can get a carbon filter for the unwanted smells, but you will need to get an inline fan, which could dramatically raise the price.

Electrical Components

Please make sure all of your electrical components are away from possible water sources.  You should place your outlets on the out side of the grow box and hung up.  The last thing you want is water in your electrical components.

Key Components

Grow Room Fan
The small desk fan provides plenty of air movement in this small grow chamber.

Indoor Grow Lights: CFLS
Here you can see two of the small ventilation fans and a few 23w CFLs. You want to get the most surface area of each bulb facing towards the plants.

Grow room fan
Notice the fan is pushing air OUT of the box. The fan at the top is drawing the heat from the lights and pushing it outside the grow box. The lights are what make the grow chamber's temperature rise. You don't want your plants to catch a fever!

CFL Grow Light
Another angle of the CFL Grow Light

Grow Room Ventilation Made Easy


-General rule of thumb: 400CFM exhaust to 100CFM intake.  Play with these numbers to see how the temperatures and air flow change.  I suggest hanging digital thermometers in various locations and heights in the grow room.  There are thermometers that also tell you the min/max temperatures from the day.  Knowing those temperatures allows the grower to understand how their daily temps are fluctuating.  Indoor grow boxes are much more efficient when they are running cool.

-Clean Green Tip:  Clean grow rooms are happy grow rooms.  Use carbon filters on exhaust fans and HEPA filters on intake fans.  Use gas duster cans to spray away any dust on fan blades.  Spider mites love to live in dust and travel through the air.  Avoid spreading a spider mite infestation with a little preventative pest control.

80mm PC Exhaust Fans
PC fans are great for small grow box ventilation and circulation.

There are a few different ways to ventilate your grow room depending on the size.  Small PC grow boxes, and any box roughly 2’x2’x4′ could be ventilated with PC fans or one small ducting fan.  Small bathroom exhaust fans would work but may be too loud for the application.  A closet grow room will need a 4″ or 6″ inline ducting fan.  The inline fan can ventilate the room and clean the air with a carbon filter.  If you are using metal halide or high pressure sodium light bulbs you will want the inline fan to push the air through air cooled hoods.  Below is an example.

2 ducting holes for air flow.
The hot grow lights are cooled in this hood. The white ducting is the entrance for the air that is coming from the inline fan. The air is pushed through the shiny duct and to the outside of the grow box.
The grow light setup
It is essential to cool hot lights in some way. You will notice healthier plants and great results!

Key to indoor gardening: Experiment with everything to see what works in your grow room.

If you understand the principles behind the practices – you will be able to make things work with what you have.  Try using a bathroom exhaust fan as the grow room exhaust.  Bathroom fans are rated with CFM just like inline fans.  They practically work the same.  Control the flow of air with quiet insulated ducting.  The noisy vibrations will certainly get annoying.  Look for more posts in the future about ventilation and grow room air circulation.

Click Here to read about the 4″ Inline Fan with Carbon Filter on Amazon.com

How to Create a Grow Room: Indoor Grow Closet


Indoor Grow Closet
This grow tent is air tight and opened with a zipper. Inline fans exchange the old air with fresh air from the outside environment.

The first step to creating a grow room is a plan.  Growing plants indoors can be tricky and you want to plan what you are going to use to achieve your goal.  Without a plan you will build a random grow room built for just growing plants indoors.  Depending on the plant you are growing, you may want different things in your grow room.  You will want to plan the type of hydroponics or drip system you are going to use.  Draw out every component of your planned Grow Tent.

Start with the frame.  How do you plan on creating a frame for your environment.  You will want an enclosed chamber.  Air tight and light tight are the goal.  Water proofing is MANDATORY. Water proofing your grow room set up will protect your house from taking heavy water damage and allow you to see any spills or leaks in your hydroponic system.  Your frame will also need to support the weight of your grow light and the heavy hood that comes with it.  You will also want to hang fans and filters from the frame so make sure you use a sturdy material.

Grow Closet Frame
The arrows point to the PVC pipes that connect to make the frame of the grow box.

Different materials will suit the needs of different growers.  The grow closet in the pictures uses 1 inch or thicker PVC pipes for the frame.  Wood and braces can construct a very sturdy grow box.  If you are going to have a lot of weight hanging from the walls and ceiling, wood will be a good material choice for the frame.  For PVC frames you will just use PVC joint connections to bring the pipes together.  You can use PVC glue, epoxy, or industrial strength tape to secure the connections.

The walls are made of black and white poly.  Black and white poly is similar to mylar on a roll but is usually cheaper.  The black and white poly is overlapped at the connection points.  Sewing the pieces of black and white poly and sealing

Grow Closet Frame
The arrows point to the joins connecting the top of the frame together. The frame is a cube so the same connections are used in every corner.

them with duct tape seems to produce a decent seal at a very low cost.  Cheap hydroponic grow boxes are hard to find, but making your own can save you quite a bit of money for a sacrifice of time.  You could also use a giant tarp to create the walls of the box, but black and white poly already reflects light.

Doors are a tricky part to building a grow room.  This is where a good plan will come in handy.  Building a wooden door is simple with the right tools.  You can cut a square hole in a wooden board to create a door frame.  Add hinges and a board that will cover the hole and you have a simple door.  To make a simple door in mylar or black and white poly you can get a tarp zipper.   The tarp zipper is meant to be sewn to the right and left sides of where the door is supposed to be.  To open the door you simply unzip the zipper.  Refer to the picture.

Grow Tent Door
The blue part is sewn to the walls and the white is the zipper door.

Once you have an enclosed grow room, you will need to ventilate it and create air circulation.  Powerful inline fans can push air through ventilated grow light hoods and air filters.  If your grow room is air tight, an exhaust fan should create negative pressure, drawing air from any cracks or holes in the walls.  Its important to draw the air out of the room by pulling air through filters before it enters or exits the grow space.  Carbon filters will remove any odors before they leave your grow room.  HEPA filters will filter out dust, pests, and mold through your intake fan.  Small grow tents will not require an intake fan if

Powerful Inline Fan
Inline fans are connected to ducting to push air through desired paths.

the temperature is low enough.  A good rule of thumb is a 4:1 exhaust/intake ratio.  That means 400 CFM(cubic feet per minute) exhaust for every 100 CFM intake.

Next hang your grow lights and the necessary accessories.  Hang your thermometers and preventative pest control gear.  You should be nearing the completion of your grow closet.  You will have to make a few minor tweaks to get exactly what you want.

Grow Room Electrical Set Up
The arrows point to the hole in the grow tent where cords enter/exit and the outer surge protector the cords plug into.

TIP: Run all of your electrical components to the outside of your grow tent.  Make a small hole for plugs to get to the outer environment.  If your cords do not reach from the inside of your grow room to the outside, you can run them to the top of the frame.  Secure a surge protector up on the wall so that it cannot be possibly touched by water.  Run the plug of the surge protector to the outside of the grow box so you have no electrical components exposed to any potential water damage.  Protect yourself and your investment!

I’ll be posting more tips and guides on grow room/grow box building in the near future.  Sign up for the RSS feed on the side bar or subscribe via email below because you won’t want to miss them!  If you have questions about building indoor grow rooms, please spark up the conversation below!