Grow Room Setup: Sheeting, Flooring, Ducting and Loft Grow Tents

A grow room is a spare room, cupboard or loft made light-tight and reflective, with a floor that takes spills and a way for air in and out. This guide covers sheeting, the floor, ducting, ceiling hangers and loft tents, step by step. The sheeting, Velcro and gaffa tape are in our sheeting section, with the ducting and fittings to go with them.

A tent in the room, or line the room?

A grow tent is already a light-tight, reflective room in a box, so in a spare room it saves lining the walls: our grow tent setup guide covers it. Lining the room uses the whole floor, whatever its shape, and Total Blackout 3m Wide, white on both sides and fully light-tight, its page says, can split it in two: one side on 18 hours of light for vegetative growth, the other on 12, the usual for flowering. A cupboard can be lined the same way.

Which sheeting for a grow room?

For a full blackout, the Black and White page points to Total Blackout, which also splits a room; Diamond Grow's embossing, its page says, matters mainly with several HID lights.

Total Blackout's 3 m width covers a wall up to 3 m high in one run, so order the distance round the room in metres, plus enough to cover the ceiling and a little for overlaps. Seal the joins with Silver Gaffa Tape, or near a lamp with Metal Tape - Heat Resistant, light-proof and rated to 110°C, its page says. Velcro Strips (50 mm wide, self-adhesive, sold by the metre with both sides) make the door: a flap of sheeting that, their page says, closes light-tight and opens as often as you like.

The floor

Lay Floor Secure first, running it a little way up the walls so spills stay on the sheet. Its page calls it a damp-proof membrane thick enough for heavy foot traffic, and says that laid over carpet it stops pests such as spider mites getting into it. Stand the pots in Flexi-Trays or a 1.2m Square Tray, which takes about nine 15 litre pots; more are under garden trays and saucers.

Grow room ventilation: ducting out of a room

A grow room works like a tent, says our intake and ventilation guide: extract high, let air in low on the opposite side, and keep extraction a little ahead of the intake.

To use a window without cutting the glass, growers commonly fit a board in the opening and fix the wall plate to that.

How big a fan? Size it with the sum in our fan and carbon filter guide. A box room 2.5 m by 2 m with a 2.4 m ceiling holds 12 m³. For one air change a minute, the demanding end of the usual rule, multiply by 60: 720 m³/h. Add about 25 per cent for the filter and ducting: an inline fan rated at 900 m³/h or more, with a carbon filter rated at or above the fan.

Hanging from the ceiling

A tent has roof bars; in a room, the hanging equipment needs fixings. The Rope Ratchets page says to put a few in the ceiling first and hook onto those; a pair holds 68 kg, enough, it says, for the heaviest reflectors and carbon filters. As a rule, fix into a joist or a batten across the joists, not plasterboard alone. Jack Chain hangs lights and small to medium carbon filters from the same fixings, and Easy-Rolls (pair), one pack per light, raise and lower it by hand, up to 10 kg.

Lofts and attics

The Budbox Pro Roof tents have a pitched roof to sit under a loft's slope: side walls 140 cm high, rising to 180 cm at the peak, so the tallest plants go in the middle.

Lofts are the hottest room in summer and the coldest in winter, our tent size guide says: vent the extraction outside, not into the loft, and insulate the ducting. For winter nights our heaters guide suggests a tube heater in each tent on a thermostat, such as Gorilla Tube Heaters (60 to 240 W). A loft floor is often bare joists: board it first, and ask a builder whether it will take wet pots and full trays. Flexi-Trays fold to go through the hatch.

Setting up a grow room, step by step

1. Plan the air and hangers. Cut the duct holes, high out and low in, and put in the ceiling fixings first.
2. Floor, then walls. Floor Secure, then sheeting, joins taped, a Velcro door and, for two light cycles, a Total Blackout divider.
3. Hang the kit. The fan and filter high, then the light and a circulation fan: for a room, our airflow guide suggests oscillating wall fans or pedestal fans.
4. Power. Several lights go on a contactor, such as the Loadstar 8-Way Contactor (up to 8 lights, on a separate timer) or the 12+2-Way Contactor Board and 16+2-Way Contactor Board, which have a built-in timer; up to four can share a Maxiswitch Quad Timer (see Step 4 of the setup guide). The contactor pages say to check the load against the rating and have an electrician check the supply for a large room. Keep plugs and leads off the floor, with a drip loop.
5. Test run. Everything on for a day and a night: look for light getting in with the lights off, and check the temperature and humidity at plant height (see grow tent humidity).

Quick answers

Is black and white sheeting light-proof?

Not completely, its page says: it reduces outside light and reflects your lamps. For a full blackout, use Total Blackout or Diamond Grow.

How do I work out the m³ of a room?

Multiply length × width × height in metres: 2.5 × 2 × 2.4 m is 12 m³. Times 60 is the m³/h for one air change a minute; add about 25 per cent for the filter and ducting.

Which grow tent fits a loft?

A Budbox Pro Roof, if your loft has the height: 140 cm at the side walls, 180 cm at the peak, in 120 × 120, 150 × 150 and 120 × 240 cm.

More Growers' Guides

• How to set up a grow tent
• Grow tent intake and ventilation
• Fan and carbon filter size
• Grow room running costs

Not sure what you need? Call the shop on 0117 971 3000 or pop in to the Bristol store and we'll help you pick.