What You Need for a Grow Room
Everything that goes in a grow room, and what each part actually does.
If you have never set a room up before, the hard part is not any one piece of gear. It is knowing what the pieces are and why they are there. Here is a whole room, labelled. Tap any number on the diagram, or read the list underneath.
Every number is a link — tap one to see what we stock for it. On a phone, swipe the diagram sideways, or just work down the numbered list below.
The parts, one at a time
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1
The tent or the room
The shell. It holds your light in, keeps your smell and your climate under control, and gives you something to hang gear from.
Common mistake: buying for floor space and forgetting height. Your light needs room to hang above the canopy, and the plants grow into that space.
See tents → -
2
The light
The engine of the whole room. Everything else exists to keep the plants comfortable underneath it.
Common mistake: buying on a headline wattage number instead of actual power draw and coverage, then hanging it too close and bleaching the tops.
See LED lights → -
3
Light hangers
Ratchet hangers let you raise the light as the plants grow, one click at a time, without taking anything down.
Common mistake: tying the light off at a fixed height. You will want to move it every week.
See light hangers → -
4
The inline fan
Pulls hot, stale, humid air out of the room and pulls fresh air in behind it. This is your climate control before you buy any climate gear.
Common mistake: undersizing it. A carbon filter and a long duct run both cut airflow, so the fan has to be rated well above the bare volume of the room.
See inline fans → -
5
The carbon filter
Scrubs the air on its way out. Sits inside the room, with the fan pulling through it.
Common mistake: putting the filter on the wrong side of the fan, or pairing a small filter with a big fan so air moves through faster than the carbon can work.
See carbon filters → -
6
Ducting
Joins the filter, the fan and the outside world. Insulated duct also cuts fan noise.
Common mistake: long runs full of sharp bends, or duct left crushed behind the tent. Every kink costs you airflow you already paid for.
See ducting → -
7
A circulating fan
Moves air around inside the room. Keeps leaf surfaces working, stops damp pockets forming, and gently strengthens stems.
Common mistake: aiming it straight at the plants at full blast, or only moving air above the canopy and never underneath it.
See fans → -
8
Humidity control
A dehumidifier pulls moisture out as the plants get bigger and drink more. A humidifier does the opposite for young plants in a dry room.
Common mistake: forgetting a dehumidifier is also a heater. In a small room it will change your temperature as well as your humidity.
See dehumidifiers → -
9
A controller or timer
Runs your lights on a schedule and your fans off temperature and humidity, so the room manages itself while you are at work.
Common mistake: running an expensive light on the cheapest mechanical timer in the shop. That is the one part you do not want drifting or sticking.
See controllers & timers → -
10
A thermometer and hygrometer
Tells you what is actually happening in the room rather than what you assume is happening.
Common mistake: reading the air near the floor or up by the light. Measure at canopy height, where the plants live.
See thermometers & hygrometers → -
11
Growing media
What the roots live in. Soil is forgiving, coco drains fast and responds quickly, and each one wants a different watering habit.
Common mistake: using garden soil from outside, or treating coco like soil and watering it on the same schedule.
See growing media → -
12
Pots
Fabric pots let air reach the rootball from the sides, which keeps roots branching instead of circling the wall of a plastic pot.
Common mistake: potting a small plant straight into a very large pot. The media stays wet far too long and the roots sulk.
See fabric pots → -
13
Nutrients
Your media will not feed a plant for a whole run on its own. A base feed plus the extras your media actually needs covers it.
Common mistake: going in at full label strength from day one, and adding extra bottles to fix a problem that was really pH.
See nutrients & additives → -
14
pH and EC meters
pH decides whether the plant can take up what you feed it. EC or PPM tells you how strong the feed actually is.
Common mistake: never calibrating. An uncalibrated meter is worse than no meter, because you trust the number it gives you.
See pH & EC testing → -
15
Trellis netting
Holds the canopy flat and even, spreads the light across more sites, and stops heavy branches folding over later on.
Common mistake: putting it up too late. Net goes in before you need it, and you tuck growth into it as it comes.
See trellis netting → -
16
What you start with
A rooted plant start or a seedling. Trays, domes and plugs keep the young ones humid while their roots catch up.
Common mistake: moving a fresh start straight under a light running at full power. Ease it in over several days.
See seed starting & cloning → -
17
A reservoir
Somewhere to mix and hold water. Letting it sit and come up to room temperature before it reaches the roots is half the benefit.
Common mistake: mixing feed in whatever bucket is handy and watering ice-cold tap water straight onto warm media.
See reservoirs →
Still not sure?
This is exactly what our free Saturday classes cover, in person, with the gear in front of you. Bring your questions and nobody will sell you anything you do not need.
Come and see it set up
Free grow classes every Saturday in the store, and a room full of this gear you can actually put your hands on. Or call and talk it through with someone who grows.
See the class calendarWebster & MilfordMatt’s Hydroponics, Webster and Milford, Massachusetts. Part of our Grower Resource Center — see also the grow calculators and feeding schedules.