Marijuana Growing Rooms: Starting Out

Guide on Starting your Marijuana Growing Rooms

How to Design your Grow Space

Setting up an optimized space for your marijuana grow room is an inevitability if you expect to start bringing in better harvests. In fact, the space you design and build is as important as the strain of cannabis and your growth strategy. This can be set up outdoors but if you’re in North America, chances are you’ll need to seriously look at setting up an indoor weed grow room.

Choose Your Weed Grow Room

The first decisions will be to choose a space, and all other aspects of your cannabis grow room setup will depend on this. In theory, you only need as little as 1 square meter, but most growers taking the step-up will choose a dedicated spare room rather than an attic corner or closet. Your weed grow room design will ultimately need to include space for watering, airflow and possibly some large hot lights.

Marijuana Growing Rooms Essentials and Needs

The room will also need the following as a minimum:

  • Power – Enough electricity, so sufficient wall sockets to run everything safely
  • Oxygen – Ventilation with inline fan and (optional) carbon filter and CO2 regulator
  • Water – Easy access with excessive hosing.
  • Security – Not too obvious for neighbours or prying eyes..
  • Temperature – The area must stay above 60°F (15°C) all year round
  • Solid walls – to maintain heat insulation, minimise fan vibration and prevent light leakage.

If you’re already in the process of scaling up you will obviously need more space than 1 square meter! A semi-pro marijuana grow room will need about 3000 cubic feet (about 100 cubic metres) which is a normal 9ft high room about 18 x 18ft in size. Every flat surface will be covered in reflective material such as mylar, ballasts will be drilled into the walls and your plants will be individual pots or troughs separated by grow lights. You will need multiple air ducts and extraction fans and an ozone generator to scrub the air of the very strong weed smell. You will also need a humidity controller and be thinking about more optimal ways to arrange plants light a suspended light rail.


Your cannabis grow room design will also need to consider the environment you need. During your plants vegetative and flowering stages the more oxygen the plant has access to the more vigorous the growth will be. In a small space, this may be as simple as opening a window from time to time. In bigger grows multiple extraction fans and free-standing fans will be necessary. These will not only replace and clean out stale air but the movement of air will mimic the external environment, which is good for the plant. It also prevents the buildup of carbon dioxide around the plants.

Ventilation is also essential as the biggest likely problem in any grow space is heat build-up. A 1000w light can increase the room temperature by 10-15°F by itself so your cannabis grow room setup will need to address heat and cooling options.

Any fan you buy will have a rating that tells you how many cubic feet of air per minute (CFM) it will move. You want to exchange the air at least 3 times per minute, ideally 5 or more. So if you have a large marijuana grow room using a 10x10x10ft space, you will need to move 1000 cubic feet of air. This means you should get at least 3 well placed 1000 CFM fans with extraction units. If you are using a closet, on the other hand, just opening the door will be enough!

At no point must the temperature fall below 60°F (15°C) or go above 90°F (32°C). Exceeding these limits even for short periods at best stresses the plant and at worst retards growth. Optimum temperature is 70-80°F (21- 27°C).

Humidity is also vital to control. Low humidity causes stress so aim to keep humidity levels at 50-60% until the final 2 weeks of flowering when the air needs to become very dry - this encourages the plant to seal itself with extra resin.

Getting a Second Grow Room

If you want to be really productive with your cannabis grow room setup, you will need a second grow room. One is kept just for vegetative growth/cloning and the other dedicated to flowering plants. The vegetative area uses standard fluorescent tube 24hr lighting and the flowering area uses HPS lights on a 12/12 cycle. With this method, while the flowering plants are going through their growth cycle the germinated seeds will have a few months to develop inside their separate room. After the flowering plants have been harvested, the plants in the vegetative area are ready to move to the flowering area.

The rooms need to be completely separate as the flowering plants need absolute darkness 12 hours per day. However, the dual room setup uses less electricity because of this. Another result is that yields will also be much more potent.


Before you start building you should be aware of what the end result will look like - you need to have a good idea before building of how much height you want from your plants, where lights and ventilation will be. Remember access to water and humidity control. Be prepared to clean the area continually, so as few grow facilities as possible should be fixed to the floor - spilled dirt, water, plant cuttings etc should be cleaned away as quickly as possible. The area also needs to be secure from pests - a single mouse can destroy a germination room very quickly!

Whatever you do have fun! Creating your own marijuana grow room is hard work but with time, energy and a goal it can be very rewarding, whatever your needs are.


Micro Lab Farms

3353 Needles Hwy

Needles, CA

(951) 266-6096