What size grow tent should I get?

Q: What size grow tent should I get?

For a first grow, a 60 × 60 cm (2 × 2 ft) to 90 × 90 cm (3 × 3 ft) tent, 160–180 cm (5.3–6 ft) tall, is the forgiving choice: one to three plants and a 100–320 W LED. A 120 × 120 cm (4 × 4 ft) tent suits two to four plants and 400–650 W. Check your legal plant limit and ceiling first.

Short answer

For a first grow, a 60 × 60 cm (2 × 2 ft) to 90 × 90 cm (3 × 3 ft) tent, 160–180 cm (5.3–6 ft) tall, is the forgiving choice: one to three plants, a 100–320 W LED and a small fan. A 120 × 120 cm (4 × 4 ft) tent yields more but costs more to light, cool and run. Grower practice. Plant-count limits vary by place, so check your local rules first: they decide the tent.

Why

Yield indoors scales with lit canopy area and light intensity ^[1]; light and planting density were among the main yield factors in a cannabis meta-analysis ^[2]. A bigger tent only pays if you can light it properly.

Light cost scales with area. A 4 × 4 ft tent has four times the floor of a 2 × 2 and needs roughly four times the light, a bigger fan and more cooling. Efficacy sets what that costs to run ^[4].

Bigger pots give bigger plants within reason ^[3], traded against feeding frequency; 11–19 L (3–5 gal) is the forgiving middle.

Height catches people out. Photoperiods commonly stretch 50–150 % after the flip.

The numbers

Tent	Plants (pot)	Efficient LED (flower)	Exhaust fan
60 × 60 cm (2 × 2 ft)	1–2 (11 L / 3 gal)	100–150 W	100 mm (4 in)
90 × 90 cm (3 × 3 ft)	2–3 (11–19 L / 3–5 gal)	225–320 W	100–125 mm (4–5 in)
60 × 120 cm (2 × 4 ft)	2 (19 L / 5 gal)	200–300 W	100–125 mm (4–5 in)
120 × 120 cm (4 × 4 ft)	2–4 (19 L / 5 gal)	400–650 W	150 mm (6 in)
150 × 150 cm (5 × 5 ft)	4–6 (19–25 L / 5–7 gal)	650–1,000 W	150–200 mm (6–8 in)

What to do

Check your legal plant limit.
Measure floor, ceiling and the nearest outlet; leave 30 cm (12 in) around the tent.
Pick the footprint; when unsure, go one size smaller.
Pick height: 140–160 cm for autos, 180–200 cm for photoperiods.
Size light and fan to the footprint.

Common mistakes

Buying the biggest tent that fits.
Too many plants, too little airflow.
No headroom for the stretch.
A big tent with a small light.

Full article: Your first grow
Guide: Choosing your setup
How many plants can I fit in my grow tent?
What wattage LED do I need?
Terms: tent · plant-count limit

Follow-up questions

Is a 2x4 or a 4x4 tent better?

A 2 × 4 ft (60 × 120 cm) tent suits two plants in 19 L (5 gal) pots and a 200–300 W LED, and fits narrow spaces. A 4 × 4 ft (120 × 120 cm) tent suits two to four plants and 400–650 W, with roughly twice the canopy and running cost. Choose 4 × 4 if you have the space, power and cooling; 2 × 4 if you don't.

How tall should a grow tent be?

A grow tent should be tall enough for pot height plus the plant plus a 30–45 cm (12–18 in) light gap plus the fixture and hangers. That is usually 140–160 cm (4.6–5.3 ft) for autoflowers and trained plants and 180–200 cm (6–6.6 ft) for photoperiods, which commonly stretch 50–150 % after the flip. Flip at about half the final height you can fit.

What size tent for two plants?

Two cannabis plants fit well in a 60 × 120 cm (2 × 4 ft) or 90 × 90 cm (3 × 3 ft) tent in 11–19 L (3–5 gal) pots, with a 200–320 W efficient LED. Two well-trained plants fill a 3 × 3 ft canopy as well as six cramped ones, with better airflow and less mould risk. Check your local plant-count limit before buying.

Sources

Rodriguez-Morrison V, Llewellyn D, Zheng Y. 2021. Cannabis yield, potency, and leaf photosynthesis respond differently to increasing light levels in an indoor environment. Frontiers in Plant Science 12:646020. doi.org/10.3389/fpls.2021.646020

Backer R, Schwinghamer T, Rosenbaum P, et al., 2019. Closing the yield gap for cannabis: a meta-analysis of factors determining cannabis yield. Frontiers in Plant Science 10:495. doi.org/10.3389/fpls.2019.00495

Poorter H, Bühler J, van Dusschoten D, Climent J, Postma JA. 2012. Pot size matters: a meta-analysis of the effects of rooting volume on plant growth. Functional Plant Biology 39(11):839-850. doi.org/10.1071/FP12049

Kusuma P, Pattison PM, Bugbee B, 2020. From physics to fixtures to food: current and potential LED efficacy. Horticulture Research 7:56. doi.org/10.1038/s41438-020-0283-7