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Grow Tent and Indoor Greenhouse Size Calculator
Pick what you are growing and how many plants. Get the tent or shelf size, the grow light watts and exhaust fan CFM it needs, what it costs to run each month at your state's rate, and a kit whose parts fit together.
Updated Oct 14, 2026
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- See the math behind every number
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Every grow tent, light and fan this tool can recommend
Tents, then lights, fans, controllers, complete kits and seed starting gear. Sizes, watts and airflow come from each listing or the maker's spec page.
AC Infinity CLOUDLAB 722 Grow Tent 2x2
- 24 x 24 x 72 in
- 4 in and 6 in duct ports
- 1 plant capacity (5 gal)
A 2x2 ft tent tall enough for one tomato or pepper plant, or a few heads of lettuce.
- 24 x 24 x 72 in
- 4 in ports (x4) and 6 in ports (x3)
- Holds 1 plant in a 5 gallon pot
- One fruiting plant at a time
$100 to $250, live price on Amazon
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AC Infinity CLOUDLAB 642 Grow Tent 2x4
- 48 x 24 x 72 in
- 4, 6 and 8 in duct ports
- 2 plant capacity (5 gal)
A 2x4 ft tent that fits along a wall: two fruiting plants or a long row of greens.
- 48 x 24 x 72 in
- 4, 6 and 8 in duct ports
- Holds 2 plants in 5 gallon pots
- Needs a 2x4 light, not a square one
$100 to $250, live price on Amazon
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AC Infinity CLOUDLAB 733 Grow Tent 3x3
- 36 x 36 x 72 in
- 4, 6 and 8 in duct ports
- 2 side doors
A 3x3 ft tent with side doors, roomy for two large plants or a crowd of greens.
- 36 x 36 x 72 in
- 4, 6 and 8 in duct ports
- 2 side doors
- Rated for 2 plants in 5 gallon pots, same as the 2x4
$100 to $250, live price on Amazon
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AC Infinity CLOUDLAB 844 Grow Tent 4x4
- 48 x 48 x 80 in
- 4 in and 8 in duct ports
- 4 plant capacity (5 gal)
The common 4x4 ft size: four tomato or pepper plants, or a salad garden.
- 48 x 48 x 80 in
- 4 in ports (x4) and 8 in ports (x5)
- Holds 4 plants in 5 gallon pots
- 80 in tall, needs about a 7 ft ceiling
- No 6 in ports
$100 to $250, live price on Amazon
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AC Infinity CLOUDLAB 866 Grow Tent 5x5
- 60 x 60 x 80 in
- 4 in and 8 in duct ports
- 6 plant capacity (5 gal)
A 5x5 ft tent for a serious indoor vegetable garden of up to six fruiting plants.
- 60 x 60 x 80 in
- 4 in ports (x2) and 8 in ports (x5)
- Holds 6 plants in 5 gallon pots
- 80 in tall, needs about a 7 ft ceiling
- Needs an 8 in fan to move enough air
$100 to $250, live price on Amazon
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AC Infinity IONBOARD S22 LED Grow Light 2x2
- Samsung LM301H
- 0 to 100% dimmer
- IP65
A 115 W dimmable board light sized for a 2x2 ft tent.
- 115 W, Samsung LM301H diodes
- Dimmer from 0 to 100%
- Works with AC Infinity controllers for scheduling
- Covers 2x2 only
$100 to $250, live price on Amazon
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AC Infinity IONBOARD S24 LED Grow Light 2x4
- 0 to 100% dimmer
- IP65
- Controller compatible
A 220 W dimmable board light shaped for a 2x4 ft tent.
- 220 W, edge to edge 2x4 coverage
- Dimmer from 0 to 100%
- Works with AC Infinity controllers for scheduling
- Rectangular, made for 2x4 only
$100 to $250, live price on Amazon
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AC Infinity IONBOARD S33 LED Grow Light 3x3
- Samsung LM301H
- 0 to 100% dimmer
- IP65
A 260 W dimmable board light for a 3x3 ft tent.
- 260 W, Samsung LM301H diodes
- Dimmer from 0 to 100%
- Works with AC Infinity controllers for scheduling
- Covers 3x3 only
$100 to $250, live price on Amazon
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AC Infinity IONBOARD S44 LED Grow Light 4x4
- Samsung LM301H
- 0 to 100% dimmer
- IP65
A 430 W dimmable board light for a 4x4 ft tent of fruiting plants.
- 430 W, Samsung LM301H diodes
- Dimmer from 0 to 100%
- Works with AC Infinity controllers for scheduling
- More light than greens need; dim it down
$250 to $500, live price on Amazon
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AC Infinity IONFRAME EVO8 LED Grow Light 5x5
- Samsung LM301H EVO
- Built-in schedule
- Daisy-chain up to 80 lights
A 730 W bar light that covers a 5x5 ft tent, with its own schedule and sunrise dimming.
- 730 W, Samsung LM301H EVO at 3.14 umol/J
- 5 x 5 ft flowering coverage
- Built-in schedule and 10 brightness levels
- Expensive; only worth it for a full 5x5
$500 to $1,000, live price on Amazon
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AC Infinity CLOUDLINE A4 4 in Inline Fan
- 29 dBA
- EC motor
- 10-speed controller
A quiet 4 inch exhaust fan with a 10-speed controller, enough for tents up to 4x4.
- 165 CFM at 29 dBA
- 10-speed controller included
- About 18 W average draw (maker spec)
- Not enough air for a 5x5 tent
Under $100, live price on Amazon
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AC Infinity CLOUDLINE A8 8 in Inline Fan
- 42 dBA
- EC motor
- 10-speed controller
An 8 inch exhaust fan for the 4x4 and 5x5 tents' 8 inch ports.
- 724 CFM
- 10-speed controller to turn it down
- About 72 W average draw (maker spec)
- 42 dBA at full speed
- Far more air than small tents need
$100 to $250, live price on Amazon
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AC Infinity Controller 75 Wi-Fi Outlet Controller
- Wi-Fi
- 2 outlets, 1,100 W
- Schedules and timers
- Temperature and humidity triggers
Switches plug-in gear on a schedule or by temperature and humidity, from an app.
- 2 outlets with separate programs, 1,100 W total
- Schedules, timers, temperature, humidity and VPD triggers
- Wi-Fi or Bluetooth app
- Switches outlets on and off; it cannot set an EC fan's speed or dim a light
Under $100, live price on Amazon
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AC Infinity Controller 69 PRO (UIS)
- Wi-Fi
- 4 UIS ports
- Temp, humidity, VPD
- Wi-Fi app
Runs AC Infinity fans and lights over their UIS cables: fan speed and light brightness by schedule, temperature, humidity and VPD.
- 4 UIS ports, each with its own program
- Sets fan speed and light brightness, not just on and off
- Wi-Fi and Bluetooth app
- Only controls UIS devices; plug-in gear needs an outlet adapter
Under $100, live price on Amazon
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Spider Farmer 2x2 ft Complete Grow Tent Kit
- 100 W LED
- 205 CFM fan + carbon filter
- GGS app controller
A 2x2 ft, 5 ft tall tent with a 100 W dimmable LED, a 205 CFM fan and carbon filter, run from a GGS controller.
- 100 W SF1000D LED at 2.5 umol/J
- 4 in fan, 205 CFM, 27 W, with carbon filter
- App control of light schedule and fan speed
- Tent is 5 ft tall, short for tomatoes
$250 to $500, live price on Amazon
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Spider Farmer SF2000Pro 3x3 Complete Grow Tent Kit
- 200 W LED
- 205 CFM fan + carbon filter
- GGS app controller
A 3x3 ft tent with a 200 W SF2000Pro LED, a 205 CFM fan and carbon filter, run from a GGS controller.
- 200 W LED at 2.7 umol/J, dimmable
- 4 in fan, 205 CFM, 27 W, with carbon filter
- App control of light schedule and fan speed
$250 to $500, live price on Amazon
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Spider Farmer 2x4 SF2000 Complete Grow Tent Kit
- 200 W LED
- 205 CFM fan + carbon filter
- GGS app controller
A 2x4 ft tent with a 200 W SF2000 LED, a 205 CFM fan and carbon filter, run from a GGS controller.
- 200 W LED at 2.7 umol/J
- 4 in fan, 205 CFM, 27 W, with carbon filter
- App control of light schedule and fan speed
$250 to $500, live price on Amazon
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Pure Garden 4 Tier Mini Greenhouse
- 27.1 x 19.3 x 63.3 in
- 14 in between tiers
- Roll-up cover
A wire shelf with a clear PVC cover and locking wheels for starting seeds indoors.
- 27 in wide tiers, 14 in apart
- Zippered roll-up PVC cover
- Locking wheels, no tools to assemble
- 24 lb per shelf
Under $100, live price on Amazon
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Barrina T5 2 ft LED Grow Lights, 4 Pack
- 2 ft bars, 10 W each
- 5000K full spectrum
- Links up to 16
Four 2 ft, 10 W full spectrum bars that link together under a seed shelf.
- Four 2 ft, 10 W bars
- Link up to 16 bars in a row
- Clips, tape and ties included
Under $100, live price on Amazon
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BN-LINK Seedling Heat Mat with Thermostat
- 20 W
- Thermostat and probe
- IP67
A 10 x 20.75 in heat mat with a thermostat, sized for one 1020 seed tray.
- 20 W, fits one 1020 tray
- Thermostat with probe, 40 to 108 F
- IP67 waterproof mat
Under $100, live price on Amazon
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AC Infinity 4 in Ducting, 25 ft
- 4 in x 25 ft
- 2 clamps
- 4-layer foil
25 ft of 4 inch aluminum duct with two clamps, to run the exhaust out of the tent.
- 4 in, 25 ft, cut to length
- Two stainless clamps included
- Keep runs short and straight for full airflow
Under $100, live price on Amazon
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AC Infinity 5 Gallon Fabric Pots, 5-Pack
- 5 gal each
- 5-pack
- Handles
Five 5 gallon fabric pots, the pot size tent plant counts are rated for.
- True 5.39 gallon capacity
- Air-prunes roots
- Machine washable
- Dries out faster than plastic; water more often
Under $100, live price on Amazon
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AC Infinity 8 in Ducting, 25 ft
- 8 in x 25 ft
- 2 clamps
- 4-layer foil
25 ft of 8 inch aluminum duct with two clamps.
- 8 in, 25 ft, cut to length
- Two stainless clamps included
- Keep runs short and straight for full airflow
Under $100, live price on Amazon
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AC Infinity 4 in Carbon Filter
- 4 in flange
- 210 CFM rated
- 12 in long
A 4 inch carbon filter that hangs inside the tent on the fan's intake side to stop smells leaving.
- 4 in flange, rated 210 CFM
- Australian virgin charcoal
- Two pre-filters and hangers included
- Charcoal wears out; replace every 12 to 18 months
Under $100, live price on Amazon
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AC Infinity CLOUDRAY S6 Clip Fan
- Oscillating
- 10 speeds
- UIS link
A 6 inch oscillating clip fan for the tent pole that moves air across the canopy; it links to a UIS controller.
- Clips to a tent pole
- 10 speeds, oscillates
- Links with UIS controllers
- Uses one of the controller's UIS ports
Under $100, live price on Amazon
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AC Infinity 8 in Carbon Filter
- 8 in flange
- 770 CFM rated
- 20 in long
An 8 inch carbon filter for 8 inch fans, rated 770 CFM.
- 8 in flange, rated 770 CFM
- Australian virgin charcoal
- Two pre-filters and hangers included
- 20 in long; takes headroom in the tent
$100 to $250, live price on Amazon
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Some of these links pay us a commission and some do not; each card says which. Commissions do not affect which models the tool picks or how it ranks them. See our disclosure.
How this calculator works
- Light target. A daily light integral for each crop: about 10 mol/m2/day for seedlings, 15 for leafy greens and herbs, 25 for tomatoes and peppers. PPFD = DLI x 1,000,000 / (hours x 3,600).
- Size. Fruiting plants use the tent maker's capacity in 5 gallon pots (1 in a 2x2, 4 in a 4x4, 6 in a 5x5). Greens use about 2 plants per sq ft. Seedlings use one 1020 tray per shelf tier.
- LED watts. PPFD x canopy area in m2, divided by 2.5 umol/J and by 0.85 for the share of light that reaches the plants in a reflective tent.
- Fan. Tent width x depth x height in cubic feet, once a minute, plus 25% for ducting and a carbon filter. The fan's duct size must match a port on the tent.
- Cost. LED watts x light hours plus the fan for 24 hours at the speed the tent needs (its rated watts x the share of its airflow you use, never under 30%), x 30 days, at your state's average residential rate.
Worked examples
Four tomato plants through the winter
- Tomatoes and peppers, 4 plants
- 16 hours of light
- US average rate, 17.3 cents/kWh
A 4x4 ft tent, about 300 W of LED, a 134 CFM fan. About $27 a month to run.
A 4x4 tent holds 4 plants in 5 gallon pots. Fruiting plants want a DLI of about 25, which over 16 hours is 434 PPFD; across 16 sq ft that takes about 304 W of LED at 2.5 umol/J. The tent holds 107 cu ft of air, so 134 CFM with the 25% allowance, which a 165 CFM 4 inch fan covers. 304 W for 16 hours plus the fan turned down to 134 CFM (about 15 W) all day is 5.2 kWh, about $27 a month.
A dozen heads of lettuce and herbs
- Leafy greens and herbs, 12 plants
- 16 hours of light
- US average rate
A 2x4 ft tent, about 90 W of LED, a 60 CFM fan. About $8.40 a month.
At about 2 plants per square foot, 12 plants need 6 sq ft, so a 2x4 tent. Greens are happy at a DLI of 15, or 260 PPFD over 16 hours, which takes about 91 W over 8 sq ft. A 220 W light dimmed to about 40% does it. With the 4 inch fan turned down to 60 CFM (about 6.5 W), that is about $8.40 a month.
Starting 4 trays of vegetable seedlings
- Seed starting, 4 trays (288 cells)
- 16 hours of light
- US average rate
One 4-tier shelf, 80 W of T5 lights and 4 heat mats. About $12 a month.
One 1020 tray per tier fills a 4-tier shelf. Two 2 ft, 10 W bars over each tray give the 8 to 12 mol/day seedlings need, 80 W in all. A heat mat under each tray gets peppers and tomatoes up in days instead of weeks; four 20 W mats cycling on their thermostats add about 1 kWh a day, for about $12 a month in all.
Frequently asked questions
What size grow tent do I need for 4 tomato plants?
A 4x4 ft tent. Makers rate a 4x4 for 4 plants in 5 gallon pots, and tomatoes need the 80 inch height most 4x4 tents have. For 1 plant use a 2x2 that is 6 ft tall, and for 2 plants a 2x4 or 3x3.
How many watts of LED do I need for a 4x4 grow tent?
About 300 W for tomatoes and peppers on a 16 hour day, and about 180 W for lettuce and herbs, using a current LED at 2.5 umol/J. Buy a dimmable light rated for 4x4, often 400 to 500 W, and turn it down to what your plants need.
How much does it cost to run a grow tent?
Light watts x hours a day x 30 x your rate, plus the fan running all day. A 4x4 of tomatoes at about 304 W for 16 hours and the fan at about 15 W uses about 5.2 kWh a day, about $27 a month at 17.3 cents. A 2x4 of greens is closer to $8.
What size fan do I need for a grow tent?
Multiply the tent's width x depth x height in feet to get cubic feet, then add 25% for ducting and a filter. That replaces the air about once a minute. A 2x4x6 tent needs about 60 CFM and a 4x4 that is 80 inches tall about 134 CFM. Match the fan's duct size to a port on the tent.
What is PPFD and DLI?
PPFD is how much usable light lands on the plants each second, in umol/m2/s. DLI is the total for the day, in mol/m2/day: PPFD x hours x 3,600 / 1,000,000. Plants respond to the daily total, so a longer day needs less light per hour.
How much light do lettuce and herbs need indoors?
A DLI of about 12 to 17. Cornell's controlled environment lettuce program grows at 17. On a 16 hour day that is roughly 200 to 300 PPFD, much less than tomatoes and peppers, which want 20 to 30.
How many hours of light do seedlings need?
14 to 18 hours a day, with 16 the common choice. Keep the light 3 to 6 inches above them; tall, pale, leaning stems mean the light is too far or too weak.
Do I need an exhaust fan in a grow tent?
Yes, for anything bigger than seedlings. Lights add heat and plants add humidity, and a closed tent quickly gets warm and damp enough for mold. A small inline fan on a speed controller pulls stale air out the top while fresh air enters a low port.
Grow tent or mini greenhouse shelf: which do I need?
A shelf with a clear cover is for starting seeds and small plants, and costs very little. A grow tent is for growing plants to harvest: the reflective lining puts more of the light on the plants, and the fan controls heat and humidity.
Can I use a grow tent in a basement or garage?
Yes, as long as it stays roughly 65 to 80 F. A cold garage needs a heat source in winter, and a damp basement may need the dehumidifier you already run. Check the tent height: an 80 inch tent needs about a 7 ft ceiling to hang the light and fan.
Marcus Reed
Founder and Editor, CrunchYourDollars
Marcus Reed builds the sizing tools on CrunchYourDollars. He is a software engineer with a long-running PC hardware and power supply habit, which is where the watts, watt-hours and surge math on this site comes from. Product specs are pulled from manufacturer data sheets, electricity rates from the U.S. Energy Information Administration, and water chemistry rules from the Water Quality Association. He is not a licensed electrician or plumber: the tools show the math and the matching models so you can make the call, and anything involving your electrical panel should be checked by a licensed pro.
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