How-to guides
Grow Tent Setup for Beginners, Step by Step
Run the numbers for your own space: fan cfm calculator and grow light calculator.
Step by step
- Choose the spot. Pick a level floor near an outlet on a circuit that isn't already loaded, with room to open every door and reach the back. A cool, dry room makes temperature and humidity much easier to control.
- Unpack and inspect everything. Lay out every part and check it against the parts list before you build. AC Infinity asks for physical defects to be reported within 30 days of delivery, and Vivosun requires visible damage to be reported within 30 days of receipt.
- Assemble the frame on a flat floor. Build the steel frame where the tent will stand. Gorilla's setup guide puts first-time assembly at 30 to 45 minutes for a 4x4.
- Fit the canvas and check for light leaks. Stretch the canvas over the frame, close every zipper and port, then sit inside with the room lights on (or shine a flashlight from outside in a dark room) and look for pinholes and gaps at zippers and seams.
- Hang the light. Hang the LED from the top bars with adjustable rope ratchets, centered over the canopy. Start at the manufacturer's recommended height for your growth stage and adjust from there.
- Install the carbon filter and inline fan. Hang the carbon filter high in the tent, where the warmest air collects, with the inline fan pulling air through the filter and exhausting it out a top port. Keep the duct short and with as few bends as possible.
- Open a passive intake. Open a low port on the opposite side for fresh air. LONGWELL recommends at least 1 square foot of passive intake per 400 CFM of exhaust so the tent stays under slight negative pressure.
- Add circulation. Clip a small oscillating fan to a pole so air moves gently through the canopy rather than straight at the plants.
- Run cables and place the sensor. Route power cords through the electrical ports, keep plugs off the tent floor, and hang the temperature and humidity sensor at canopy height, out of direct light.
- Do a 24-hour dry run. Run the light, fan and controller for a full day and night cycle with no plants. Note the temperature and humidity at lights-on and lights-off, and adjust fan speed before anything is growing.
Setting up a tent is mostly about doing things in the right order. Build and light-proof the tent before anything heavy goes in, get air moving before the light runs for long, and run the whole system empty for a day so you can fix problems before plants depend on it.
The steps above are the short version. Below is what to watch for at each stage.
Before you start
You will need the tent, a light, an inline fan with a carbon filter and duct, a clip fan, a controller or timer, and a temperature and humidity sensor. If you haven’t picked these yet, start with the best grow tents or a complete 4x4 kit.
Size the exhaust before you buy it. Our fan CFM calculator uses LONGWELL’s published formulas: one air exchange per minute, plus about 25% for a carbon filter, 5% per 5 feet of flexible duct and 10% per 90-degree bend.
Building the frame and canvas
Assemble on the spot where the tent will live; a fully built tent is awkward to move. Push every pole fully into its connector so the frame is square, or the zippers will strain.
Gorilla’s recommended order is frame first, then canvas, then zip the door closed to check light-tightness before installing anything inside.
Light-leak check. Light leaking in during the dark period can disturb some plants, and light leaking out is a nuisance. With the tent zipped, check the zipper tracks, corners and ports. Small pinholes can be covered with foil tape on the inside.
Hanging the light
Use the rope ratchets supplied with the light so you can raise it as plants grow. Start from the manufacturer’s recommended hanging height. As a reference for how much height matters: in Coco For Cannabis’s PAR test of the Mars Hydro FC-E4800, raising the light from 13 to 16 inches lowered the average light level slightly (751.2 to 731.5 µmol/m²/s) but brought nearly every corner above 500. Even coverage often matters more than peak brightness.
Not sure if your light is strong enough for the space? Our grow light calculator and 4x4 grow light guide cover that.
Ventilation: the part beginners get wrong
The most common mistakes are pushing air through the filter instead of pulling it, long sagging duct runs, and no intake.
- Filter at the top, fan pulling. Hot, humid, smelly air rises. Hang the filter high, attach the fan so it draws air through the filter, and exhaust out of a top port.
- Short, straight duct. Each 90-degree bend costs roughly 10% of airflow by LONGWELL’s figures.
- Passive intake low and opposite. At least 1 square foot per 400 CFM of exhaust. The tent walls should pull in slightly when the fan runs; that’s negative pressure, and it keeps odor inside.
- Run the fan below full speed. LONGWELL suggests an EC fan will usually sit around 50–70% speed. A controller that ramps speed with temperature or humidity does this automatically.
Our inline fan guide covers fan choice in detail.
Heat and power
Every watt your light draws ends up as heat in the room: about 3.4 BTU per hour per watt, according to THCFarmer’s guide, which works out to roughly 1,640 BTU per hour for a 480 W light. If your room is already warm, plan for more exhaust or room cooling.
The same guide estimates the running cost of a 480 W light at 15 cents per kWh at about $26 a month on 12 hours a day and $39 on 18. Check your own rate.
Plug everything into a properly rated outlet or the controller’s outlets, and keep connections off the floor in case of spills.
The 24-hour dry run
Run the light on its schedule with the fan and controller for one full cycle before plants go in. Note:
- Temperature at canopy height at the end of the light period
- Humidity when the lights switch off (humidity usually rises when the tent cools)
- Fan noise at the speed you need
If humidity stays high even with good exhaust, you may need a dehumidifier; see dehumidifiers for grow tents.
How this guide was put together
The steps follow manufacturer setup guidance (Gorilla), published ventilation formulas (LONGWELL), warranty terms from AC Infinity and Vivosun, and THCFarmer’s member-data guide. We did not set up a tent for this article; see how we research.
FAQ
How long does it take to set up a grow tent?
Gorilla puts first-time assembly of a 4x4 tent at 30 to 45 minutes. Allow longer for hanging the light, filter and fan, and a full day for a dry run before plants go in.
Where should the carbon filter go in a grow tent?
At the top of the tent, where the hottest and smelliest air collects, with the inline fan pulling air through the filter and pushing it out through the duct. LONGWELL notes the filter's CFM rating should be equal to or higher than the fan's.
Do I need an intake fan?
Usually not for tents up to about 5x5. LONGWELL recommends passive intake vents of at least 1 square foot per 400 CFM of exhaust, which keeps the tent under negative pressure so odor doesn't escape.
How much heat does a grow light add to a room?
Every watt ends up as heat, about 3.4 BTU per hour per watt. THCFarmer's guide works out that a 480 W light adds roughly 1,640 BTU per hour.
How much does it cost to run a grow tent light?
THCFarmer's example: a 480 W light at 15 cents per kWh costs about $26 a month on a 12-hour schedule and about $39 on 18 hours. Multiply your light's real wattage by hours and your own electricity rate.
Sources
Specs and measurements change between product revisions. We list the date we last checked each source.
- Manufacturer Gorilla Grow Tent Pro 4x4, product page, Gorilla Grow Tent. Checked Nov 13, 2026.
- Reference Grow tent fan size calculator: formulas, LONGWELL Fans. Checked Nov 13, 2026.
- Manufacturer AC Infinity warranty program, AC Infinity. Checked Nov 13, 2026.
- Manufacturer Vivosun warranty policy, Vivosun. Checked Nov 13, 2026.
- Owner feedback Best grow lights by tent size (member grow data), THCFarmer. Checked Nov 13, 2026.
- Independent measurement Mars Hydro FC-E4800 PAR test and review (tested June 29, 2021), Coco For Cannabis. Checked Nov 13, 2026. Earlier production unit; 48 × 48 in test area.