When choosing where to build a groom room you need to take into consideration how many plants you want to sustain, what kind of lighting fits your heat and electricity needs and whether you want to grow in soil or hydro. A cannabis grow can be small (in a closet or crawl space) or HUGE (full buildings & warehouses) but the general needs of cannabis plants will always be the same. Lets say that you have a 10ft X 10ft space in a garage. First you need to choose a tent (a light tight portable grow tent that just needs to be popped up) or a wooden/metal frame that you can construct yourself and line with reflective material or flat white paint. Once you have your room set up its time to think about ventilation.
You need to put a hole near the top of your grow room in order to duct out hot air from lights and excess humidity!
Ventilation is needed in order to bring in fresh, Co2 rich air from outside and pull hot stale air from the grow environment. First thing you need to do is choose a type of fan, inline fans which come in 4″ 6″ and even 10″, these fans can be used to pull air through your light hoods in order to take heat and humidity directly off the bulbs and out of the room. Fans can also be installed high and low in the room (high for outtake because heat rises and low for intake because the air will be cooler and Co2 sinks to the ground) but this would only be fully useful for an air tight larger scale room. Any intake should have some sort of filter to keep out unwanted pests and mold spores! In this 10 X 10 room you should place at least two osculating fans to keep the air from becoming stagnant on the leaf surfaces and to also move around your plants creating stronger branches to support even bigger flowers! Lighting Lighting choices are covered Here and each have their own strengths and weaknesses but generally speaking HPS is the go-to lighting choice for most cultivators. When it comes to this 10 X 10 we would recommend 600 Watt HPS bulbs for flowering because the 600 W bulbs put out the most usable light per watt than any other wattage bulb! (Pro Tip: Try mixing spectrum’s IE mix in a few blue spectrum UV lights to aid in maximizing THC potency!)