The perfect cannabis grow room

The perfect cannabis grow room

Indoor cannabis cultivation has never been more popular and the great news is it’s never been easier to create the perfect cannabis grow room. Cannabis is a resilient plant, but if you want to get the most out of your crop, you must cultivate your weed in as close to perfect a habitat as possible.

Our guide to the perfect cannabis grow room will help you plan, prepare and operate the optimal indoor grow room. No matter the cannabis strain you choose to crop, nor the cultivation style, success is measured in grams of bud come harvest.

Every successful cannabis crop starts with a grow plan before even a single seed is germinated. The first step is to establish a suitable area for use as your indoor cannabis garden. This can be a spare bedroom, an attic or a cellar.

Just make sure it is private and absolutely will not be disturbed by any third party for the duration of the grow. Use common sense and avoid growing on the ground floor or close to the entrance of your property.

A cannabis grow is the definition of a “need to know” operation and only the grower should be aware, that a grow is underway on the premises. This is your personal unacknowledged “green site”.


The simple solution to grow room construction is to buy a cannabis grow tent. These days grow tents come in a range of sizes and you can easily find one that’s a perfect fit for your grow.

Moreover, grow tents are typically lined with highly reflective silver Mylar and they are also 100% light-tight, so your plant’s dark cycle won’t be interrupted. LED growers can even get special white Mylar interior grow tents for maximum reflection of the LED spectrum.

Using the entire floor space of a spare room and/or building your own grow room is unnecessary for the contemporary home grower and ill-advised. DIY grow rooms are usually only required for commercial cannabis cultivation and unless you’re filling a multi-kilo order for a dispensary or club stick with a grow tent.

Furthermore, grow tents are very affordable and the cost of building your own custom grow room could easily exceed the price of a tent. Also, stretching Mylar tightly and light-proofing can be a tricky business.

As for using the whole room, the same reflection and light sealing problems will arise. Sure it’s the cheapest to start up with and you can always just paint the walls with dull white paint.

But a big odour problem could be in lurking, waiting to perfume your grow room and perhaps the whole dwelling as soon as the transition to flowering begins.

Larger carbon filters and more powerful fans will be required if you crop the entire room. Every time you open the door, the scent of marijuana will escape and if you enter during the dark cycle, the light from the hallway will leak in. Get a green bulb for the room if you insist on pursuing this option and entering during lights out.

Perhaps the most overlooked advantage of the grow tent is how easy they are to maintain and run. Cleaning is no sweat, all you need is some soapy water and a cloth. Hanging lights, extractor fans and carbon filters from the ceiling of a grow tent is a lot less work and doesn’t require any power tools.

Rope hangers or chains, cable ties and a roll of duct tape are all you need to secure all of the heavier grow room equipment and light weight accessories like ducting into position in a grow tent. The modern grow tents create the perfect microclimate for cannabis cultivation and you should definitely invest in at least one.

Two or more m² grow tents are usually possible to fit in most spare rooms. A simple rotation system can be implemented by the grower.

By using one grow tent for the vegetative growth phase or to house mother plants and cuttings, the second grow tent can be used simultaneously to bloom another batch of mature plants. This kind of flexibility is not possible using the whole room.


How much light per m²In general terms, if you are using an old school HID setup with a standard configuration, MH for vegging plants and HPS for flowering housed in a reflector, then 400-600W lamps supply ideal coverage per m².

Whereas the latest LED full spectrum grow lights provide comparable if not slightly better output with approximately 50% of the power draw, the newer 200-400W systems should suffice without any bulb switching required.

CFL bulbs in the cool white spectrum are ideal for the vegetative growth stage, economic 150-300W CFLs are a great alternative to hot running MH lamps and help to keep internode spacing tight, as CFLs can be positioned just a few cm from the canopy as opposed to the typical 50-60cm required for both HID and powerful LED lights.

Blooming with CFLs is not recommended, as they just don’t deliver high bud yield. Great supplemental lighting for bloom, but not a viable independent option.

In the interest of good housekeeping and safety make sure all ballasts and electrical connections are outside the grow tent and nowhere near water, this is especially important with hydro grow ops. Mount everything on the wall if possible and always keep it tidy so you won’t be tripping over wires.




Before you rush out to the hydroponics store or start furiously searching online growshops for cultivation equipment, come up with a grow plan. First, you must be clear on your objective. Are you aiming for marijuana self-sustainability? Or supplementing your stash with occasional crops?

Next, you must carefully choose cannabis seeds. Only then will you be ready to put the pieces of your grow-op together.


Grow tents are the obvious choice. These days, there is a fantastic selection of ultra-reflective, mylar-lined grow tents designed in various shapes and sizes. Whether you have a large empty garage or limited floor space in the spare bedroom, you can find a grow tent to fit your needs. A grow tent is a self-contained and sealed-off environment that few DIY grow-ops can match.

If you do decide on a DIY grow-op, don’t expect to save much cash. But you will definitely have some extra labor. A light-tight grow tent can be assembled in minutes right out of the box, while a custom grow room must be covered in highly reflective mylar or matte white paint from wall to wall by you.

Plus, you will likely have to plug cracks and holes in surfaces to prevent light leaks. Moreover, unlike a grow tent which can be disassembled rapidly, a full grow room conversion is a permanent change to the property.


A 600W digital dimmable ballast with a dual-spectrum HPS bulb and basic reflector can be found for bargain prices these days in most grow stores. Complete lighting kits like this give you the option to upscale your grow-op later with minimal additional hardware costs. Ideally, a dimmable ballast with 4 settings: 250W, 400W, 600W, and 660W is preferred.

Micro-growers can use this system in a tight space on the lower settings. Or if you have plenty of room, you can get a larger reflector and push it to the limit. Watch out for bundle deals, and you can grow with pro tools at discount prices.


A surge-protected digital timer plug with a programmable LED display will keep your light schedule on track and under control. Photoperiod cannabis strains are sensitive to disturbances to the light-dark cycle, and even hardy autoflowers will perform better with a consistent schedule.

Make no mistake, this is an essential piece of kit.


You really need three fans. An extractor fan to draw out hot stale air, an intake fan to suck in cool fresh air, and an oscillating fan to create an artificial breeze for the cannabis plants. How powerful your intake and outtake fans need to be depends on the size of your grow space and how much light you plan to use. Use an online calculator to figure this out before you buy any fans.

Carbon filters are the most popular choice when it comes to odor control. Keep your ducting straight when making connections for optimal performance. Remember, a filter is not forever and will need replacing after a few months. Otherwise, a pungent weed aroma will return.



Cool, fresh air in; hot, stale air out. That’s how every grow-op should run. Air exchange is a critical factor in cannabis cultivation. You need a window, a hole in the wall, or a vent with two access points for an inlet and an outlet.

Your intake will be joined to the inlet with ducting to suck in air. Meanwhile, your outtake fan, also joined with ducting to the carbon filter, will exhaust the hot air via more ducting through the outlet.


How many plants do you really need? And how much floor space do you have? Still unsure? Be cool and keep it simple. 11l black square pots with plenty of drainage holes in the bottom are a solid choice for an ordinary home-grow.

This is a pretty versatile, inexpensive container suitable for a high-volume SOG or a single monster plant. Moreover, you can transplant directly or start in a smaller container and pot-up later.


If you are growing at home, it makes sense to grow organic. Soil is more forgiving than coco or hydro substrates, and is ready-to-grow right out of the bag. Natural, cannabis-specific soils are available in 50l bags for less than €20.

The best soils are a premixed blend of peat, coco, and perlite, with light to heavy nutrient contents. If you want to supplement with organic fertilizers, a light mix is best. Or keep it simple with a richer soil and just add water. The choice is yours.


This little device is another grow room essential that doesn’t get enough attention. A thermo-hygrometer will give you the data you need to maintain optimal environmental conditions.

Accurate temperature and RH readings are vital. Make sure this unit has a fresh battery and is inside the grow-op from day 1.


If your thermo-hygrometer is displaying worrying data, you need to make adjustments. The grow-op needs to be a cannabis-specific microclimate. The following grow room accessories are not essentials for every grower, but have come in handy in our experience.

In the case of low RH in vegetative growth, you may need to add a humidifier. However, in contrast, with high RH during flowering, a dehumidifier is the solution. During cold winter months, you may even need to have a heater running in the grow-op during the dark cycle to keep temperatures above a minimum of 15°C.

Good airflow is essential to temperature control and maintaining optimal environmental conditions for cannabis plants to thrive. Intake fans need to be securely connected to straight ducting to keep the fresh air flowing in from either a window or vent.

Similarly, the outtake fan and carbon filter ducting must be tight and as straight as possible. Get this right and not only will the plants appreciate it, but pungent marijuana aromas won’t be a problem.

To mimic the outdoor breeze carefully position pedestal fans and/or clip-on fans around the grow tent. Make sure not to place fans too close or turned up on too high a setting; we’re shooting for a calm breeze rather than a tornado.


Once you get your grow show perfectly tuned from equipment to nutrients, you need to maintain the perfect conditions. A simple thermometer with built-in hygrometer will enable you to keep an eye on the microclimate in the grow tent. Make accurate adjustments with this inexpensive essential piece of kit.

Now it’s time for you to get busy and decide which marijuana strains and which particular cultivation method are the right fit for your perfect cannabis grow room.


  • Light bulb, reflector and ballast
  • Switch Box
  • Fan + Filter
  • Ventilator
  • Pots
  • Thermometer
  • Hygrometer
  • Reflective Walls
  • Humidifier ( if necessary ... )
  • Heater ( if necessary ... )