Grow Tent vs Grow Room for Cannabis: Pick the Tent First
A 4x4 grow tent costs $100 to $500 and holds 16 sq ft of canopy. A built grow room runs $2,000 to $8,000. Pick the tent first.
Short answer
A small cannabis grow tent setup uses 2 ft by 2 ft or 2 ft by 4 ft of floor space. The parts list is short: a tent, a 100W to 200W LED bar light, a 4 in inline fan with a matched carbon filter, a 6 in clip fan, fabric pots, a timer, and a hygrometer. Parts cost $300 to $600. A 2x2 tent yields 2 oz to 4 oz of dried flower in 10 to 14 weeks from seed under a 100W light.
Grow Tent vs Grow Room for Cannabis: Pick the Tent First
Tent size and height
Pick a tent with 60 in of height or more. A 2x2x4 ft tent fits one plant in a 5 gal pot. A 2x4x5 ft tent fits two to three plants. Short tents limit light distance and plant height. Measure the ceiling and the door width before you buy.
small cannabis grow tent setup
Light
Use 30W to 40W of LED draw per square foot. A 2x2 tent needs 100W to 150W. A 2x4 tent needs 200W to 250W. Look for a PPFD spec, not a marketing watt number. Target 400 to 600 PPFD in veg and 600 to 900 PPFD in flower at the canopy. Keep 18 in to 24 in between the light and the top of the plant.
Air and smell
An inline fan pulls air through a carbon filter and out of the tent. Size the fan to move the tent volume once every 1 to 3 minutes. A 2x2x4 ft tent holds 16 cubic feet, so a 4 in fan rated 100 CFM or more is enough. Run a clip fan inside the tent to move air across the leaves. Run the exhaust 24 hours a day during flower. A carbon filter lasts 12 to 18 months.
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Pots and medium
Use 3 gal to 5 gal fabric pots. Fabric pots air-prune roots and dry faster than plastic. Soil or a peat and perlite mix works for a first grow. Coco coir needs feeding every day and suits growers with a pH meter.
Climate targets
- Temperature: 70 to 80 F with lights on, 65 to 70 F with lights off
- Humidity: 60 to 70% in veg, 40 to 50% in flower
- Light schedule: 18 hours on and 6 off in veg, 12 and 12 in flower
- Water pH: 6.0 to 6.5 in soil
What it costs to run
A 100W light plus a 15W fan draws 115W. Four weeks of veg at 18 hours a day uses about 58 kWh. Eight weeks of flower at 12 hours a day uses about 77 kWh. At $0.15 per kWh the grow costs about $20 in power.
Common mistakes
- Buying a light sold in "equivalent" watts with no PPFD number
- Skipping the carbon filter, then dealing with smell in week 6 of flower
- Filling a 4 ft tent with a tall sativa that doubles in height
- Running exhaust on a timer and trapping humid air
Check before you buy
Confirm the plant count and canopy limits in your state. Some states cap home grows at 6 plants and require a locked space. A tent with a zipper counts as a closed space in most rules, but read the local text.