November 27, 2017

Setting up a grow room can be challenging to the novice grower and plants that don't have the right environment can produce disappointing yields. If you're just starting out then you need to know all the basics to get the best start. This guide will support you by making sure all the boxes are ticked when it comes to creating the right environment. If you have any questions then please leave a comment so we can help you and others who may have the same questions.

Choosing a Grow Space

The minimum space required to start your grow is around 1.2 x 1.2 meters. This will allow you to maximise the light available from a single 600w grow bulb, which is generally considered to be the most efficient bulb to grow with. You should also make sure your space has access to power and water.

Grow TentsGrow tents are ideal for hobby grows and will provide the perfect environment for your plants to thrive. Our grow tent kits come complete with everything you need to get started! For larger grows you may want to consider converting an entire room to suit your needs, however even then you may find it easier to control the environment by setting up a series of large grow tents rather than trying to maintain an entire room.

Grow room ventilation, lights and pumps will generate some noise, so ensure that the space you choose is away from any areas where the noise could disturb you or your neighbours!

Seal in the Light

Plants need consistent light which will be provided by your grow lights. If your grow space also has another source of light, such as a window, then this can confuse the plants and lead to them being stressed. 

If you are using a grow tent then this will already be light proof, otherwise you should use blackout sheeting to seal up any external light sources. You should also line the space with reflective sheeting to prevent the light from being absorbed by walls, floors etc. This will allow your plants to maximise all of the available light by reflecting the light into hard to reach places, such as the lower branches on bushy plants.

Special grow room work lights are available should you need to tend to your plants outside of the usual photo-period. These use a green frequency of light which the plants do not absorb which allows you to work while the plants remain undisturbed.

Setting up Your Lights

As a minimum, you will need one 600w grow light system for each 1.2 x 1.2 area.

Each lighting system comprises of the following elements:

Grow Lamps

These are the grow bulbs used in your lighting system, there are various lamps available for propagation, vegetative growth and flowering cycles, the main lamp types used are summarised in the table below:

Lamp Type Usage
Metal Halide Vegetative
Sodium Flowering
Dual Spectrum HPS Vegetative & Flowering
LED's Vegetative & Flowering
Flourescent/CFL Propagation, Vegetative & Flowering



The ballast controls and regulates the power supply to your grow bulb. Some lower wattage bulbs have a built in ballast, as do all CFL and LED grow lights.

Ballasts come in two types, magnetic and digital. Magnetic ballasts are generally cheaper to buy but are bulkier and will generate much more heat than the electronic versions which contain a microchip to control the voltage.


Grow light reflectors sit above the lamp and bounce the light downwards towards your plants. The most effective reflectors have a hammered texture, smooth angels and a wide surface area. When using high wattage bulbs it is advisable to use an air cooled reflector to help prevent your grow space from getting overheated.

Timers & Contactors

Timers allow you to automate your lights and equipment to fit your photo-period. Most domestic timers are not designed to handle the demands placed by high wattage lamps and will often develop faults after continued use. To avoid this look for a heavy duty timer which is designed for indoor growing.

Contactors prevent power surges and are vital to protect your grow room equipment.

Light Hangers

Lights and reflectors will need to be supported by adjustable hangers to allow for plant growth, these should be sturdy enough for the job and regularly checked for any damage or rot.

Choosing the Correct Lamp Wattage  

You will need to use the optimal lamp wattage to suit your grow space and also allow for additional headroom as the bulb wattage increases, this will allow for the additional heat which could damage your plants and also help to prevent your grow room from overheating.

The table below provides a summary of coverage and hanging distances for the most common metal halide and HPS bulbs.

 Wattage Max Coverage Min Hanging Distance
150w 0.6m x 0.6m 7 Inches 
250w 0.8m x 0.8m 10 Inches
400w 1m x 1m 12 Inches
600w 1.2m x 1.2m 16 Inches
1000w 1.5m x 1.5m 21 Inches


Mastering Ventilation & Climate Control

Plants consume CO2 and also produce moisture while the heat from the lamps will allow the air to hold more moisture and become humid.  This can lead to a stale environment for the plants where the CO2 is depleted and humidity and temperature levels are too high.

Ventilation systems can avoid this issue by drawing in fresh air and expelling the stale air.

Extraction & Intake

You need to extract stale air and also intake fresh air to your grow room.

Extraction fans will draw out the stale air and are rated at m3/hour, to work out how much air needs extracting per hour you can use the following formula:

Grow room space ( L x W x H) x 60

Now you have a baseline figure to work out how powerful your extraction fan needs to be, you will also need to consider the following factors which can affect your final requirements:

  • Cool Environment (E.g. Basement): + 20%
  • Warm Environment (E.g Loft): -20%
  • Air Cooled Reflectors: - 30%
  • Long Ducting: + 20%

Extractor fans can also be fitted with carbon filters for odour removal and fan silencers to reduce noise. Acoustic ducting will also help to keep noise to a minimum.

Your intake fan should be around 20% less powerful than your extractor fan, this prevents your tent from blowing up like a balloon and helps to keep odour contained.

Grow Room Setup Tips

  • Avoid setting up your grow in carpeted areas as these can contain bugs and bacteria, as well as being difficult to keep clean
  • If you're growing on a concrete or cold floor then consider elevating your pots to avoid the roots from getting too cold
  • Running your lights and equipment at night will help to keep the grow room cooler and save on electricity
  • Use a hygrometer and thermometer to keep your grow room environment at optimal levels
  • Keep cables tidy and out the way
  • Avoid coiling up your light and power cables as these can cause them to get hot
  • Keep electrical items away from water unless they are designed to be submerged
  • Keep a powder fire extinguisher handy just in case!

If anything is unclear or you have a question about a setup which hasn't been covered, then please let us know in the comments and we'll do our best to provide you with our expertise.

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