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Grow tent 120×120 UK: size, poles and leaks

Updated: October 2026

You are measuring a spare room for a grow tent 120×120 UK growers keep recommending, and the advert in front of you is shouting about canvas denier. Denier is a yarn weight. It does not tell you whether the poles will hold a filter, whether the ports match your duct, or whether the zippers leak light. This page stays on tents. The two shells in our [grow shop comparison](/hub/plant-accessories/grow-shop) are the Secret Jardin Hydro Shoot HS120 and the AC Infinity CLOUDLAB 844, with amazon.co.uk prices from 19 October 2026. A qualifying purchase can earn us a commission at no extra cost to you.

You are measuring a spare room for a grow tent 120×120 UK growers keep recommending, and the advert in front of you is shouting about canvas denier. Denier is a yarn weight.

Our top picks

AC Infinity AC Infinity CLOUDLAB 844 4×4 tent

Best overall

AC Infinity AC Infinity CLOUDLAB 844 4×4 tent
8.9/10about £239.00
View offer
Secret Jardin Secret Jardin Hydro Shoot 120 cm tent

Alternative

Secret Jardin Secret Jardin Hydro Shoot 120 cm tent
6.4/10about £85.99
View offer
On this page
  1. 1.Footprint and height before brand
  2. 2.Poles, ports and what the roof must carry
  3. 3.Hydro Shoot versus CLOUDLAB 844
  4. 4.Light leaks and zippers
  5. 5.Buy the poles, then inspect the zips

Footprint and height before brand

Start with the floor, then the height, then the brand. A 120 × 120 cm tent is 1.44 m², and you still want about 20–30 cm for the zips, the clearance Greens Horticulture suggest. The room needs nearer 1.6 to 1.8 m of free wall. A 4×4 is the same footprint: the CLOUDLAB 844 is 121.9 × 121.9 cm, and it will not hide beside a bed. Both tents are about 200 cm of canvas, 200 cm on the Hydro Shoot and 203 cm on the 844. Filter and duct often sit on the roof, so the ceiling must clear more than the printed height. Shop ranges put one or two plants in 60 × 60 cm. Two chillies do not require 120 cm, and a 50 W bar does not light 1.44 m².

Poles, ports and what the roof must carry

The roof carries the filter, the fan and the lamp, often tens of kilograms, for months. The CLOUDLAB listing states 1-inch steel poles and a 150 lb maximum, about 68 kg, plus extra bars. That amazon.co.uk line is the number you can point at. A higher shop figure is marketing. Denier does not stop a leak if the zipper flap is twisted. The 844 lists four 4-inch ports and five 8-inch ports, so extraction can sit high and the intake low. The Hydro Shoot table lists neither ports nor a hanging load. Greens’ HS120 roof note is up to 30 kg. Near that weight, you are at the edge of their figure, and amazon will not back you up. Match the fan to the port you have.
AC Infinity AC Infinity CLOUDLAB 844 4×4 tent

Testsieger

AC Infinity AC Infinity CLOUDLAB 844 4×4 tent
8.9/10about £239.00
View offer

Hydro Shoot versus CLOUDLAB 844

The Hydro Shoot HS120 is 120 × 120 × 200 cm, 2.88 cubic metres and 14 kg, with 4.2 from 22 reviews. Alloy-steel frame, mylar inner, polyester outer. The two UK texts are short and positive. A German review likes the space once it is up and says the canvas is miserable alone. No printed load, no confirmed tray, no light in the box. The CLOUDLAB 844 is 121.9 × 121.9 × 203 cm and 19.9 kg, with 4.6 from 6,741 reviews: stated 1-inch poles, 2000D canvas, diamond mylar, extra bars, a tray and a tool bag. No light, fan or filter. UK reviews praise the build and also describe leaks, including a pin-cushion seam. The price gap is review volume and a stated load, not a complete kit.

Light leaks and zippers

Leaks matter when a dark period can be broken by a streetlamp. They matter less for herbs on a timer. Tent closed, room dark, lamp on, eye at the zipper. A twisted zip shows light even on thick canvas. The 844’s 2000D claim has not stopped UK leak reports, so denier is not a blackout certificate. A Spanish review says zipper leaks were refused after 30 days. Look in the first week. Neither tent includes that lamp. Do not hang it from a corner seam. No British Standard in our sources approves a hobby tent. Assembly, including a second person for the Hydro Shoot canvas, is in how to set up a grow tent.

Buy the poles, then inspect the zips

If you want several fruiting plants, clearance around 120 cm, and a lamp in the hundreds of watts, the 844 is the shell with a stated 150 lb load. If you want the cheaper 120 cm chassis and a helper for the canvas, the Hydro Shoot is that buy, and you still do not have a printed load. If the room is a box room or the crop is two chillies, 120 cm is more tent than you need. In every case, look for light at the zippers in the first week.

Common questions

Is 120×120 cm the right home size?
It fits when you want several fruiting plants, clearance around the tent, and a lamp in the hundreds of watts. It is too much tent for two chilli plants, which shop charts put nearer 60 × 60 cm. A smaller room needs a smaller tent we have not scored.
How tall a tent do I need?
You need canvas tall enough for the plant plus the lamp gap, and a ceiling taller than the canvas because the duct and filter take space above it. These two tents are 200 cm and 203 cm. If your ceiling is 210 cm, a roof-mounted filter will fight you. Measure to the plaster, not to the picture rail.
Does 2000D matter more than the poles?
2000D is a heavier fabric claim than a cheap 600D shell, and the 844 prints it beside 1-inch poles and a 150 lb load. The poles carry the filter. UK reviews still report leaks, so inspect the zips in week one.
Will the Hydro Shoot hold a filter and an LED?
The amazon specification does not say. Greens publish a roof figure up to 30 kg for the HS120, which may cover a modest filter and a light if you hang them properly, and it will not comfort you if your filter is heavier. The 844 states 150 lb. If the load is unknown, do not hang first and measure the sag later.
Does the tent include a light?
No, on either listing here. The 844 includes the tent, bars, ports, a catch tray and a tool bag. The fan, the filter and the lamp are all separate purchases you add later. A finished-room photo is not the parcel.

Related pages

Best grow tent kit UK

Grow tent kit buying guide

LED or HPS grow light

Grow shop

How to set up a grow tent before your first sowing

Sources

Public UK sources used for this comparison. Shelf prices, stars and review counts are the amazon.co.uk figures captured for these seven listings on 19 October 2026.

  1. RHS, How to sow seeds indoors (retrieved 19 October 2026)
  2. Misuse of Drugs Act 1971, section 6 (retrieved 19 October 2026)
  3. CPS, Drug offences (retrieved 19 October 2026)
  4. GOV.UK, Drugs penalties (retrieved 19 October 2026)
  5. Electrical Equipment (Safety) Regulations 2016 (retrieved 19 October 2026)
  6. OPSS, YIKEDAN LED grow light 2408-0204 (retrieved 19 October 2026)
  7. CANNA UK, PK 13/14 (retrieved 19 October 2026)
  8. One Stop Grow Shop, beginner tent setup 2026 (retrieved 19 October 2026)