LIGHT BULB :Cannabis plants tend to grow best under HID lamps (MH or HPS). These cannabis grow lights range from 240-1000W and you will need to choose according to how big your grow room is and the intensity of light you want to give your plants. In large grow rooms 1000W lights will provide a much better quality grow, but create much more heat and cost you a lot in electricity. In a very small grow room, such as a cupboard, a 1000W light is going to be overkill, (and probably a fire hazard). The typical wattages used in most reasonably sized grow rooms are 400 -600W.

REFLECTOR :The reflector is a reflective shield that goes behind the light bulb. This bounces back any light towards the plant that would have otherwise been lost upwards.

BALLAST :The ballast is an essential safety box. HID lights require a lot of raw power and can be very demanding and damaging to your homes electricity grid. The ballast acts as limiter, making sure that the lights’ energy source is effectively managed without putting too much stress on your electricity network. If you plug HID lights straight into the mains power then you run the risk of overloading your circuits and causing a fire.

SWITCH BOXThe switch box is an indispensable tool for the indoor grower. It allows you to set timers to turn your equipment on and off at certain intervals. You will need a fairly powerful one in order to handle the power of the HID lights. A cheap 30 euro switch box will not be enough. The very top end switch boxes can be used to control pretty much everything in your grow room, including lights, ventilation, thermometer temperature control, CO2 release and automated watering devices. This quality of switch box is very expensive and only really used by advanced cultivators in very advanced grow rooms. In a basic set-up you only really need one powerful enough to manage your lighting.

FAN + FILTERA filter usually hooks up to your ventilation system (fan). It is an important part of keeping your grow room discreet by filtering out unwanted odours. If you do not have one then you may find that your home starts to smell of weed, potentially attracting unwanted attention. The most effective way to prevent this is to use the fan in combination with an active carbon filter.
A ventilation system has several functions within your grow room. It is used to:
Boost yields when used in conjunction with a slow carbon dioxide release (this is an advanced growing technique and is not necessary for small growers)
The movement of air helps keeps your plants healthy. As they grow, they use various gasses and if the air supply is not replenished, it can have a negative effect on your cannabis plants' growth. The movement of air will also help you remove any excess heat and humidity from the room caused by your lights. A slight breeze from the fan is also beneficial for your plants as they grow in the vegetative stage; simulating a natural wind, which encourages stronger stem, branch and root growth. This is because your plant thinks it needs to be stronger to resist the wind.
Hot air rises, so it is usual for the air intake to be at floor level and the air outtake to be above your lights. This allows for decent circulation - as the hot air is taken out of the room it is displaced, drawing upwards the air from below. This system is a good way of both airing your plants and replacing hot air with cool air.

POTSPots come in all shapes and sizes. You will find that for growing marijuana you need fairly large ones, (10-20 liters), as cannabis plants grow a strong and intensive network of roots. Ideally your pots should have perforations/holes in the bottom and be placed into large trays. This allows excess water to run out of the pot and into the tray, making sure your plants are not over watered. Professional growers will sometimes not use pots with holes because they have a great feel for their strain and know exactly how much water it needs. This is not recommended unless you are absolutely sure you know what you are doing. It also makes flushing your weed very hard should you need/decide to.

THERMOMETERThis essential piece of equipment will help you maintain the optimum level of heat in your grow room. You ideally need to maintain a temperature of 75 degrees Fahrenheit (23.8 degrees Celsius), but slightly warmer temperatures can help some strains grow faster. It is possible to buy digital thermometers with set parameters that may be used in conjunction with an advanced room control/switch box, heater and ventilation system. This will completely automate the rooms’ temperature control but is very expensive to maintain.

HYGROMETERA hygrometer, much like a thermometer is used to measure conditions within the grow room. A hygrometer measures humidity. Cannabis grows optimally between 40-80% humidity. If you have a good air circulation set-up, then you should not need to worry too much, as the introduction of fresh air goes a long way in helping to maintain humidity levels. If you are struggling to maintain the right levels then it is possible to buy humidifiers and de-humidifiers depending on what you need. As with temperature control, an advanced set-up can automate the control of humidity, but it is in no way necessary.

REFLECTIVE WALLSIt is important to make sure there is minimal light loss in your grow room; the more light you can get to your plants the better they will grow. Therefore, it is essential to make sure you make the walls of your grow room reflective. Any reflective surface (including your bulb reflector) should be white or made of polished metal.
A very common mistake is to use aluminum foil as a reflective surface, I mean, why not?  It’s reflective. Wrong!  Aluminum foil is a very poor reflector of light and is very heat conductive. It has a reflectivity of 30-60% at the best of times, is hard to keep clean and tears easily. The best solution is a cheap, matt white paint. Walls painted with white paint tend to have 99% reflectivity, are easy to maintain and are not a fire hazard to your grow room and home.
It is a common misconception that shiny or glossy materials are very reflective; in fact they are less reflective than the colour white (do not confuse light reflection with image reflection). Light is technically “white” as it contains all of the visible colour spectrum, thus white things reflect every part of the light spectrum without absorbing any of it.

HEATER:​ It is always handy to have a heater on stand-by in your grow room. If your bulbs die you may find that the temperature in the room drops dramatically, particularly if you live in a colder climate. A heater will help minimize damage and downtime of the plant whilst you get replacement bulbs in situ.