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Growing your own cannabis can be a very rewarding experience, but in order to do it right, you’ll need a grow room to provide the right conditions for crops to thrive.
Since cannabis plants are notoriously temperamental, the growing conditions need to be just right if you want your hard work to result in healthy yields.
In this ultimate guide to building a grow room, we’ll be walking you through the process of creating the perfect environment for your marijuana plants, from finding the ideal space to figuring out the lighting.
By the end of this article, you’ll have all the information you need to get growing!
Choosing A Space For Your Grow Room
Obviously, the first thing you’ll need to do when building a grow room is choose a suitable space.
This can be more difficult than it sounds because you need to make sure that your chosen space ticks all the boxes when it comes to factors such as size, temperature, ventilation, and more.
Here is everything you should consider while looking for a space to transform into a grow room:
The good news is, you don’t need to find a large space to turn into your grow room. In fact, the best grow rooms are often based in smaller places such as closets and mini tents.
We’ll be exploring some examples of ideal growing spaces later in this guide, but for now, what you need to know is that the minimum recommended size for a grow room is 4 x 2 x 2 feet.
A room of this size should provide enough space for novice growers to house all their plants as well as the necessary equipment, although if you’re planning to grow a lot of plants, you’ll need to increase the size of your chosen space accordingly.
Temperature is key to growing a thriving crop of marijuana plants. If the temperature in your grow room is off, you’ll have a hard time growing healthy plants with good yields.
Of course, you can install heaters in your grow room at a later stage, so your chosen growing space doesn’t need to be the perfect temperature from the outset.
However, you do need to ensure that you’ll be able to efficiently regulate the temperature of the room.
This is one of the main reasons why closets are one of the most highly recommended grow spaces (see below), because it’s easier to regulate the temperature of a room inside your home.
As we’ll discuss later, basements and garages are also popular grow spaces, but if you choose this type of space to grow your cannabis plants and you live somewhere with colder weather or fluctuating temperatures, you will probably need to install some heaters.
Arguably, humidity is even more important than temperature when it comes to the health of your marijuana plants, so don’t neglect this factor.
Again, like temperature, the humidity of your chosen space doesn’t have to be perfect from the start.
However, if you don’t want to have to run a humidifier or dehumidifier constantly (which can get very expensive) you should try to choose a space that is neither too dry nor too humid.
With that being said, we’ll be discussing methods of humidity control later in this guide, so if you’re worried that the humidity levels in your otherwise ideal grow space aren’t optimal, you can fix this quite easily.
Cannabis plants rely on CO2 levels to thrive, and in order for CO2 to circulate through your grow room, you’ll need to prioritize proper ventilation.
If you’ve chosen to grow your marijuana plants in a closet or cupboard, you’ll need to be prepared to make some adjustments to the space so that stale air doesn’t stick around and harm your plants.
For example, you may need to install some intake fans and an exhaust to make sure that the airflow in the space is continuous.
Flooring material probably isn’t the first thing you think of when it comes to setting up a grow room, but it’s actually more important than you think.
Firstly, since your grow room will be a relatively humid space, you’ll need to ensure that your chosen floor material is resistant to moisture, otherwise you could end up with a mold problem on your hands.
Many first-time growers assume that concrete is an ideal flooring material since it’s so durable, but in reality, the porousness of the material means that it will soak up humidity from the air and release moisture and chemicals as it breaks down.
This could potentially be harmful for your plants.
If your chosen grow space doesn’t already have a suitable flooring material and you don’t want to have to take up the existing floor and replace it, you can usually create a solid flooring situation by covering concrete flooring with paint or epoxy.
Alternatively, you can put down vinyl flooring or mylar.
Accessibility And Discretion
We don’t recommend growing cannabis if doing so is not legal in your state of residence.
However, even if marijuana is legal where you live, the reality is that your neighbors might not appreciate the smell or light leakage from your growing room, so it’s best to make an effort to be as discreet as possible.
If your growing space is somewhere people can see into or light can leak out of, it’s better to avoid colorful LED lighting and ultra-bright HID lighting (we’ll discuss your lighting options in a moment).
While you obviously want your grow room to be accessible to you, you don’t want other people or animals getting into the space.
Therefore, it needs to be located in an area that other people can’t easily access without your permission or knowledge. This is especially important if you have children or pets in your home.
The last thing you want to do is contaminate your cannabis plants through improper cleaning practices, so when you first start constructing your grow room, you should make sure it’s as clean and free from contaminants as possible.
Rake up any rugs or carpets in your room because they can harbor pathogens, bacteria, and even parasites that can eat up your crops.
It’s also best to clear the room of any items that aren’t directly related to your growing project to eliminate potential sources of contamination.
When your grow room is clear, you should disinfect all the surfaces before adding any other items.
Safety is of the utmost importance when it comes to putting together a grow room.
Your grow room will probably contain several electrical appliances and outlets, and since you’ll either need a built-in water source like a sink or buckets of water coming in and out of the room for watering, you must be very careful not to allow sources of electricity to come into contact with water.
If you have reflector cables in your growing space, you should ensure that they are never coiled up since this can cause them to overheat and create a fire hazard.
Examples Of Grow Spaces
Grow rooms can be made out of unexpected places and spaces, but there are 4 main spaces that work really well for grow room transformations. These are as follows:
While garages may need some work to turn them into proper grow spaces in terms of temperature and humidity, they are some of the most popular places for building grow rooms because they are conveniently connected to homes and aren’t typically relied on for living areas.
The issue with turning a garage into a grow room is that in addition to needing heaters and humidity control appliances to maintain an optimal growing environment, you may need to soundproof your garage if you don’t want your neighbors to pick up on the noise of your ventilation system.
Additionally, it’s difficult to stop the odor of cannabis from escaping a garage, and since garages lead outside, this can be an issue.
That’s why people who grow in garages will usually invest in a grow box or a grow tent to enclose the plants in a more discreet way.
Like a garage, a basement is a good space to create a grow room.
In fact, it’s more discreet because the average basement doesn’t lead outside, so it’s easier to stop the noises and odors that come with growing cannabis from being noticed by neighbors and passers-by.
Temperatures in basements tend to fluctuate, becoming very warm in the summer and very cold in the winter, and there is often more humidity in a basement than is needed for growing cannabis.
However, all of these things can be controlled with the right appliances.
You’ll need to seal any windows in your basement to stop the smell from escaping, although you may need to install a ventilation system to stop the air from getting stale.
The beauty of a grow tent is that it can be placed in virtually any room, providing an enclosed space in which the temperature, humidity, and ventilation can easily be controlled without having to do a lot of construction work.
Grow tents are also pretty affordable, especially when you consider that they come with all the necessary equipment and are most often made of mylar sheeting which reflects light onto your plants.
A closet or wall cabinet can also be transformed into a great growing space for cannabis plants, as long as it is big enough.
Obviously, you’ll need to install some form of ventilation because your average closet doesn’t have much air circulation, but since your cabinet is likely to be inside your home, you can control the temperature and humidity more easily than in other popular grow spaces like garages.
You could even build a cabinet from scratch if you don’t already have a suitable one at home.
How To Build A Grow Room: Step By Step
We’ve already discussed how to choose and start preparing a grow room, but if you’re planning to actually create a grow room from the ground up, you’ll need a step-by-step plan.
Here’s everything you need to know and do to turn any space inside or outside your home into a space for your cannabis plants to thrive:
You Will Need
Before you get started, in addition to an empty room to transform, you’ll need to have the following tools and equipment:
- Wood or other building materials to construct your frame
- A measuring tape
- Scissors, screw drivers, and a drill
- Reflective paint or materials
- Equipment for ventilation
- Growing lights
This is just the bare minimum of what you will need, and depending on the plan you come up with for your room (see below), you might need to install more equipment.
For example, if there isn’t already a sink in your room and you don’t want to have to carry buckets back and forth all the time, you might need to purchase and install one.
The key to success when building a grow room is meticulous planning.
That’s why we recommend not only drawing a diagram of what you want your grow room to look like, but actually building a 3D model before you start working on the real thing.
Building a model of your grow room might seem like a lot of effort, and it may not feel necessary at the time, but this is the best way to get a real feel of what the space will look like and, more importantly, how functional it is likely to be.
Use your tape measure to take all the necessary measurements, making sure to write them down as you go.
From there, you can start working out how your plants and equipment will fit in the room, bearing in mind that you need to leave a fair amount of distance between plants and things like heaters, fans, and dehumidifiers.
Be sure to consider the height of your space as well. Remember, depending on the cannabis varieties you’ll be growing, you might need anywhere up to 10 feet of space.
Using the measurements you took earlier, you can calculate the square footage of your room and base the number of plants you’ll be able to grow on this calculation.
As a rough guideline, you can expect to grow between 3 and 6 pants in a 2-foot by 4-foot area.
Creating A Frame
Once you have a completed model to work from, you can start on the real construction work. The first step of this process is building your frame.
Usually, this will be a cuboid structure with 3 horizontal wooden bars across each of the sides. You’ll want to leave the top and bottom unobstructed.
Consider fixing the frame to one of the walls in your grow room to increase its stability. Remember, your frame will need to be able to support your fans and lighting appliances, so it needs to be sturdy.
Covering And Light-Proofing
Once your frame is finished and sturdy enough for your standards, it’s time to cover it, either with reflective materials or additional walls.
It’s faster to cover the frame with reflective material because if you add walls, you’ll need to add reflective materials inside as well.
Try to make sure that light is reflecting into the frame from every side since more light reflection will increase the yield of your cannabis plants.
The best reflective materials are:
- Flat white paint. This reflects anywhere up to 85% of the light in your grow room and doesn’t cost a lot, so it’s good if you’re on a tighter budget. If you’re worried about mold, you can prevent growth by adding a fungicide to the paint before you apply it.
- Mylar. A popular light proofing and reflecting material, this is one of the best ways to ensure a good yield from your crops. Make sure to get aluminized/metalized mylar, though, since other varieties aren’t as good for reflecting.
- Black and white nylon. If you need to stick to a budget, you may prefer to use nylon sheets in black and white. The white nylon sheets reflect the light while the black material keeps it inside the frame.
Before you start actually using your grow room, you should inspect all walls and connections to make sure no light will leak through.. You can use tape (light proof tape, ideally) to block light leaks.
Airflow And Ventilation
Ventilating your grow room is easier than you might think. You don’t necessarily need a complex ventilation system – in most cases, portable fans will make a big difference.
You may also need some intake fans and exhaust fans to keep the air circulation fresh and constant.
For the best results, install your intake fan near the floor and put the exhaust fan on the opposite wall towards the ceiling. Adding a CO2 filter and an oscillating fan on top of this will ensure perfect ventilation.
Temperature And Humidity Control
You’ll want your grow room to stay at around 50% humidity most of the time, although optimal humidity levels can vary depending on the growing stage your plants are in.
In terms of the temperature, you should aim to keep it between 70 and 80 degrees fahrenheit. This, again, will vary depending on the plant variety you have chosen to grow.
You can use a thermometer or humidity sensor to measure the temperature and humidity in your grow room, and if you need to adjust either factor, you can introduce humidifiers, dehumidifiers, or portable heaters.
You can even just place a heating blanket underneath your growing pots during the winter if you need to warm your plants slightly.
If you are using heaters in your grow room, make sure they’re always on a timer so you don’t accidentally overheat your plants.
As we discussed earlier, you will want to clean your grow room before you start construction, but you will also want to clean your room before you introduce any plants to the space.
This will ensure that contaminants from your construction materials don’t harm your plants.
You’ll also want to put a collection tray in your grow room to collect any water, leaves, or soil that would otherwise fall on the floor during the growing process.
These trays should be swept out and cleaned on a regular basis to prevent the accumulation of mold or bacteria.
Choosing Your Grow Light
We’ve talked a lot about lighting in this guide, but we haven’t provided you with much information on what lighting you should use in your grow room.
That’s because lighting is such a key factor in successful marijuana growing, so we felt it needed its own dedicated section.
There are 3 main types of lighting cannabis growers typically use to get the best results from their plants in terms of health and yield, and these are:
HID or High-Intensity Discharge lights are incredibly bright, so if you use this kind of lighting, you will never need to worry about whether your plants are getting enough light.
However, bear in mind that if you want to get the most out of your HID lights, you’ll need to attach them to a reflector so the light reflects directly on the plants.
It’s very important to leave enough space between HID lights and your plants, though, since they burn very hot and could cause a fire hazard if you don’t pay attention to distance and ventilation.
Some things to bear in mind with HID lighting is that because it’s so bright, it can draw unwanted attention if your room isn’t light-proof.
Also, these lights can be expensive to run because they consume so much energy.
LED lighting is another popular form of lighting in the growing space. They don’t run hot, so you don’t have to worry about burning your plants, and they don’t consume much energy, so they’re budget-friendly.
Just make sure to avoid colorful LED lights (such as purple lights) if you don’t want to alert all of your neighbors to what you’re doing.
Many marijuana growers like to use fluorescent lighting because they run cool and don’t use very much electricity.
They also provide a full light spectrum, which is a recipe for success when it comes to the health of your plants.
If you choose to go with fluorescent lighting, though, you must do your research and figure out what bulb shape and size will be best for you.
For example, you can have T5 grow lights, which are the best choice for indoor grow spaces due to their flat, wide shape, or CFL bulbs, which are ideal for smaller spaces.
Hopefully, you should now have all the information you need to create your own cannabis grow space.
The best way to successfully build a grow room for marijuana plants is to start by creating a 3D model based on the measurements of your chosen space.
From there, you can decide where to place your plants and equipment, using measurements of temperature and humidity in the space to decide which appliances to install.
Safety should always come first, so pay close attention to hot appliances and water sources throughout the design and construction process.
I’m an avid gardener and cannabis enthusiast. You can usually find me in my garden caring for my plants or at my computer crafting helpful blogs for my readers.