DIY Grow Room: Build Your Cannabis Indoor Grow

If you want to start growing your own medicine but can’t find (or afford) , here's how to build a tent for cheap.
Author Enzo Schillaci
28 July 2020
9 min read
DIY Grow Room: Build Your Cannabis Indoor Grow

Contents:

If you live in a place where cannabis is illegal and you want to grow your own, the best option is to grow your plants indoors. A grow tent allows you to control the temperature, humidity, and most importantly, prevent light leaks and eliminate the smell. Despite what everyone thinks, you can build a cheap grow box if you know which materials to use and how to build it, here are a couple of homemade grow tent ideas to help you save money and start growing in no time.

1. Main requirements

Before starting to build your grow tent, you need to have a couple of things in mind.

Even though you can grow cannabis anywhere you want, what differentiates a grow tent from any other growing space is its ability to keep light from leaking, being airtight so the exhaust fans can work properly and you can keep a stable temperature and humidity.

You can build good stealth grow tent as big as you want, with everything you need to, from the appropriate structure for the light fixtures to the exhaust fan and filter, and as long as you can accomplish the main requirements, you will have a fully functioning grow tent.

A DIY grow tent doesn't stay behind a grow tent you would buy at a grow shop if you use good materials and take your time to do it and despite seeming like hard things to do, it is fairly easy.

 

Diy grow room

To avoid any problems, you want your indoor grow room to be light-proof, ait-tight and waterproof.

Light-proof

The grow tent needs to be 100% light-proof, this is to avoid the waste of precious light and avoids your plants from stressing out.

When flowering, you need to provide a 12/12 light cycle, if there is a source of light near your grow tent when the lights are turned off, that light might get in and stress your plants, making them revegetate or becoming a hermaphrodite.

This is why a grow tent must be 100% light-proof, it will not only allow you to maximize light usage but will also avoid any problems with your plants.

Waterproof

If you’re planning to build your grow tent with plywood for example, you have to cover the inside with a waterproof material like a plastic sheet (or something similar).

By doing this you keep the wood dry and avoid rotting (keeping mold away from your grow tent). It will also make it easier to clean and you won’t have to worry about water leaking to your floor.

Air-tight (temperature, humidity, and airflow) 

As you may know, growing indoors allows us to control and adjust the temperature, humidity and intensity of the airflow, because of this, your grow tent must be air-tight.

If you fail to keep air inside, your exhaust fan won’t work properly, it won’t keep the cannabis smell contained and it will be easier to get bugs.

An air-tight grow tent is a must when growing in places where cannabis is illegal, failing to contain smell (and light) in the tent can easily cause neighbors to report you to the police, so make sure you check this a couple of times throughout your growing cycles, as this can easily be fixed and will save your from a lot of headache.

2. Different types of builds

When building your grow tent, you can make it as big as you want to and out of anything you have available as long as you make it light-proof, air-tight and waterproof.

 

Diy grow room: structure of a grow tent

Structure of a DIY grow tent.
 

The easiest ways of making it are with a metal (wood or plastic) structure and a plastic sheet covering it, or building a closet-like structure with plywood.

3. Building your own indoor grow step-by-step

To start building your own indoor growing space you’ll need some basic materials and tools, some you might already have at home.

Grow tent

A grow tent is the best DIY grow space because (depending on how you build it) you can easily disassemble it when you need to and then mount it again without needing anything else.

To build a grow tent, you will need wood, metal or plastic poles, and a plastic sheet.

The size of the poles obviously depends on the height and size of the grow tent you want to build, but here’s an example to build a 1x1x2 grow tent.

First, you’ll need to cut and assemble the poles into something like this:

 

Diy grow room: Structure of a grow tent

Basic structure of a grow tent.
 

As you see in the image above, you’ll need 8 poles with 1m each for the top and bottom part of the structure, 1m x 3 poles for (E) and (F) and 2m x 8 poles for (C) and (B). If you want to make it easier to handle and assemble, you can cut the 2m poles into 1m x 8 poles and connect them with PVC fittings.

You will also need 8 PVC 3 way knees to connect (A) to (B) and (A) to (C), and 6 PVC Tees to connect poles (E) and (F) to (A).

If you’re planning on using a heavy light fixture (or more than one) and an exhaust fan with a carbon filter, it’s better to use metal poles so the structure can bear the weight.

After you have all the poles and connectors ready, you need to cut the plastic sheet.

 

Diy grow room: black plastic sheet

Black plastic sheet used to build a grow tent.
 

The plastic sheet should be measured on the grow tent before cutting so you don’t have to redo it, make sure it doesn’t have holes to avoid light leaks and if it doesn’t get too hot where you live you can use 2 layers of the sheet to make the tent more resistant.

Even though the plastic sheet is waterproof, you will need to coat the inside of the grow tent with a material that reflects light like a mylar sheet or a white plastic sheet.

 

Diy grow room: mylar

Mylar used to reflect light in a grow tent.
 

Note: Instead of using mylar, you can use a white plastic sheet, it won't reflect light as good as mylar but it works great if you can't find mylar easily. 

Grow "box"

A grow box is easier to build, although you cannot disassemble it effectively and the plywood can rot after a while because of the humidity and eventual water spills. To make a grow box out of plywood and wood beams, you’ll need a structure similar to the structure of a grow tent. 

 

Diy grow room: structure of a grow box

The structure of a grow box.
 

You need 1m x 8 wood beams for (A), 2m x 8 wooden beams for (B), and 1m x 2 or x 3 beams for (C). The amount of beams you need on top depends on the weight of your light fixture, exhaust fan, and carbon filter.

After you have the structure mounted, you need to cut the plywood to start closing the sides of your grow box.

You’ll need 1x1m x 1 and 1x2m x 4 plywood sheets, remember they need to fit perfectly so there are no light leaks and the grow box is as air-tight as it can be.

One of the 1x2m plywood sheets will need to be cut in half (for the door). You’ll also need 4 door hinges so you can open and close your grow box properly.

 

Diy grow room: grow bow

The sides of a grow box along with the light fixture, exhaust fan, and filter.
 

Tip: Even though it is not obligatory, you can glue pieces of rubber sheet where the plywood sheets meet and in between the door to make you maintain the temperature and humidity levels.

Because wood can get wet and rot, it’s a good idea to cover the inside with 2 layers of material.

4. Objective

The result of your DIY grow tent or grow box should be something similar to this:

 

Diy grow room: improvised grow room

Home-made indoor grow box.
 

With some minor differences, obviously.

After you have everything set up there are a couple more things you need to have your growing space up and running, these things are: 

  • Ventilation system
  • Carbon filter
  • Light fixture

Unfortunately, you cannot make them at home (unless you have experience with electronics), so you’ll have to buy them.

5. Exhaust fan

The exhaust fan usually goes on the top part of the grow space and is connected by a tube to the carbon filter.

The exhaust fans ensure a good air exchange, this is crucial to the growth of your plants because the air exchange will provide the CO2 your plants need while letting out oxygen.

A good ventilation system along a decent-sized fan will also help your plant’s stem develop tougher, helping them support the heavy buds in the flowering stage.

6. Carbon filter

The carbon filter goes directly connected to the exhaust fan (sometimes it’s connected by duct tubing) and it’s what will eliminate the strong cannabis smell before letting the air out, a carbon filter is crucial if you are growing indoors in a place where cannabis cultivation is illegal, this will avoid problems with your neighbors and the police.

 

Diy grow room: carbon filter

A carbon filter will eliminate the typical cannabis smell, this way you avoid getting in trouble.
 

Have in mind that when making your own grow tent or box you will have to make the holes where the duct tubing goes in and out.

7. Light fixture

As you may know, light is vital for growing any kind of plants, including cannabis.

Depending on the kind of light fixture you’re planning to use, you’ll need to make some adjustments so you can adjust the height of your light.

 

Diy grow room: light fixture support

If your lights are too heavy, remember to test the structure to see if it can withstand the weight before starting your next grow cycle.
 

Some lights are heavier than others or maybe you’ll need to use more than one light fixture. So remember to test the structure you’ve made with the exhaust fan, carbon filter, and light fixtures (and maybe add more support) so you don’t risk killing your plants if the equipment falls on them.

8. In conclusion

If you want to start growing your own cannabis you don’t need to spend a lot, despite the cost of a ventilation system and lights, you can easily build your own indoor growing space by yourself.

Make sure you’re taking the appropriate measure so it’s solid, steady, and can support the growing equipment and you’ll have a fully functional grow tent while spending way less than buying one at a grow shop.

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