Growlab 120 3ft 11inch x 3ft 11inch (4×4) grow tent

The GrowLab 120 is a 4×4 portable horticultural grow room measuring 3ft 11in wide by 3ft 11in deep by 6ft 7in tall. It is designed to house a complete ventilation, lighting, and growing system, and features a thermally insulating reflective interior, a powder-coated steel frame, adjustable ducting ports, and a removable waterproof floor that simplifies cleanup between grow cycles.

GrowLab 120 Specifications

The following table lists the core dimensions and construction details for the GrowLab 120 (model HGC706835) as documented in the manufacturer’s product information.

Specification	Value
Model	GrowLab 120 (HGC706835)
Footprint	3ft 11in × 3ft 11in (approximately 4×4 ft)
Interior height	6ft 7in
Frame material	Powder-coated steel (thicker gauge than previous models)
Roof load capacity	100 lbs (via roof cross-members)
Fabric heat reflection	97% of radiant heat reflected
Interior reflectivity	Highly reflective (improved vs. previous models)
Floor	Waterproof; removable second floor for cleaning
Viewing windows	Clear viewing windows included
Ducting ports	Multiple intake/exhaust ports; two opposite each other at reflector level
Toxicity	Non-toxic; no off-gassing under light and heat

Why Choose the GrowLab 120

The GrowLab 120 is built for growers who want a dedicated, light-tight environment that holds a complete system — lights, fans, filters, and a growing medium — without requiring a permanent installation. Here is what distinguishes it from simpler tent designs:

• Thermally insulating fabric: The tent material is designed to reflect 97% of all radiant heat, which helps maintain interior temperature consistency and reduces the thermal load on your climate control equipment.
• Powder-coated steel frame: The frame is coated to resist rust and is built thicker than prior GrowLab generations, providing a more stable structure for heavy lighting fixtures or CO₂ equipment hanging from the roof cross-members.
• 100-lb roof load rating: Cross-members across the roof are designed to support up to 100 lbs, which covers most HID or LED fixtures along with carbon filter and fan combinations.
• Adjustable ducting ports — no clamps or reducers needed: The intake and exhaust ports use an adjustable attachment system so standard ducting fits directly without requiring adapters. Two ports are placed opposite each other at reflector level, which is the correct position for air-cooling a reflector hood.
• Removable second floor: The inner floor layer can be lifted out for rinsing after a crop cycle, which makes cleanup practical rather than a chore.
• Non-toxic materials: The fabric is documented as completely non-toxic and will not off-gas under the elevated heat and light conditions that occur during a grow cycle.
• Clear viewing windows and moveable cross-members: Observation windows are included on the GL120 model (not all GrowLab sizes offer this), and the roof cross-members can be repositioned to adjust lighting height or hang accessories at different points.

Best Uses for the GrowLab 120

The 3ft 11in × 3ft 11in footprint places this tent in the practical 4×4 category, which is one of the most common sizes for home and small commercial setups. The 6ft 7in interior height adds headroom for tall plants or for hanging both a light and a carbon filter simultaneously without crowding.

• Vegetative and flowering cycles with HID lighting: The 100-lb roof capacity and reflector-level air-cooling ports make this tent a good match for 600W or 1000W HID setups. If you are considering a high-output bulb, the Eye Hortilux 600W Ceramic HPS is a well-regarded option in this footprint.
• Full-cycle cultivation in a limited floor area: The 4×4 footprint fits in a spare room corner, closet, or utility space. The tent encloses the environment without requiring structural modifications to the room.
• Hydroponic or soil systems up to 4×4: The waterproof floor liner protects against nutrient solution spills and condensation drips. The removable inner floor makes it practical to run recirculating systems inside the tent.
• Setups requiring observation between cycles: The clear viewing windows on the GL120 let you check on plants, read meters, or inspect foliage without opening the door and disrupting the light cycle.
• Growers moving between locations: The tent is a portable structure that can be disassembled and reassembled, making it suitable for growers who rent or expect to move their setup.

GrowLab 120 vs. Similar Grow Tents

The 4×4 grow tent category includes a range of options at different price and quality levels. The GrowLab 120 occupies the mid-to-upper segment of that range, distinguished primarily by its frame gauge, fabric specification, and port design. Here is how it compares to what you might encounter in a comparable search:

Frame construction: Entry-level tents commonly use thinner-gauge, uncoated or paint-dipped poles that are more susceptible to bending under heavy loads and to surface oxidation in humid grow rooms. The GrowLab 120 uses powder-coated steel, which adds a bonded protective layer rather than a surface coat, giving it better long-term rust resistance. The frame is also documented as thicker-gauge than GrowLab’s own prior generation.

Fabric and insulation: Many budget tents use standard mylar-lined Oxford cloth. The GrowLab 120 uses a thermally protected fabric rated to reflect 97% of radiant heat. This matters particularly in warm ambient environments or when running high-wattage HID systems, where tent-wall heat absorption can work against your climate control.

Port system: Lower-cost tents often use fixed-diameter fabric rings for ports, which require reducers or clamps to connect standard ducting. The GrowLab 120 uses adjustable attachment points that accept standard ducting directly. The dual opposing ports at reflector level are positioned specifically for air-cooled reflector hoods, a design detail that not all tents share.

If you are comparing the GrowLab 120 to another 4×4 option in our catalog, the Grow Shop Outlet 48×48×78 grow tent is a direct size comparison worth reviewing before making a decision.

Compatibility

The GrowLab 120 is a passive structure — it does not itself draw power or require electrical connections. Compatibility considerations are about what equipment you plan to run inside it.

Lighting: The 100-lb roof load capacity and 6ft 7in interior height accommodate most residential and small commercial lighting configurations. This includes HID setups (HPS and MH) as well as panel-style LEDs. The reflector-level ducting ports are sized for inline fan and duct combinations typically used with air-cooled reflectors. Confirm your duct diameter against the port specifications before purchasing a fan.

Ventilation: The tent includes multiple intake and exhaust ports. Two are positioned opposite each other at reflector level for active air-cooling of a lighting system. Remaining ports can be used for passive intake, carbon filter exhaust, or sensor cabling. The adjustable port attachments accept standard duct diameters without reducers.

Growing systems: The waterproof floor liner is compatible with hydroponic systems, deep water culture buckets, and soil containers up to the tent’s footprint. The removable inner floor layer allows drainage or spillage cleanup without requiring full tent disassembly.

Controllers and accessories: The moveable roof cross-members provide flexible anchor points for CO₂ emitters, environmental monitors, or ratchet hanger systems. The tent does not include built-in electrical features, so all controllers and timer systems are external to the tent structure.

Usage Guidelines

The GrowLab 120 is not a self-contained growing system — it is the enclosure around one. These guidelines describe how to use the tent’s specific features effectively once it is assembled.

Roof cross-members and load management: The cross-members snap into position and can be moved to different points along the frame to distribute load or adjust where equipment hangs. Spread load evenly across multiple cross-members when hanging heavy fixtures. The 100-lb capacity is the combined rating for the roof structure, not per cross-member.

Ducting ports: Place the primary exhaust fan connection at one of the reflector-level ports if you are using an air-cooled reflector. Connect intake at the opposing port at the same level. This creates a horizontal airflow path through the reflector hood. For environments where the reflector does not require active cooling, use the ports for standard top-exhaust and bottom-intake ventilation instead.

Viewing windows: The clear windows on the GL120 are designed for visual inspection without opening the tent. During photoperiod-sensitive stages (lights-off periods), use the viewing windows rather than the door to check plants, as opening the door introduces light.

Floor management: The removable inner floor layer should be lifted and rinsed between crop cycles. For hydroponic systems, place a secondary tray under your reservoir or buckets to contain any drips above the inner floor layer. The outer waterproof floor layer is a permanent part of the tent construction.

Zippers: The GrowLab 120 uses heavy-duty zippers. Do not force a zipper that meets resistance — check for fabric caught in the teeth. Lubricating the zipper teeth with a wax-based zipper lubricant periodically extends their service life. Seal unused port openings with the included covers to maintain the light-tight environment.

How to Set Up the GrowLab 120

1. Sort the frame components: Lay all poles and connectors out on a clean floor. Identify the corner connectors, top-frame pieces, vertical uprights, and roof cross-members. Group them before beginning assembly to avoid searching mid-build.
2. Build the base frame: Connect the lower horizontal poles to the corner connectors to form the rectangular floor frame. Insert the vertical uprights into each corner connector.
3. Complete the top frame: Attach the upper horizontal poles to the tops of the vertical uprights. Insert the roof cross-members into their mounting positions. The cross-members snap into place — position them where you plan to hang your lighting and fan.
4. Drape the fabric shell: With one person holding the frame steady, drape the fabric shell over the top frame. Align the door zipper panels with the door openings and pull the fabric down evenly over all four sides.
5. Secure the shell: Fasten any velcro straps or corner ties to hold the fabric flush against the frame. Check that the zipper seams are straight and that no gaps exist at the base corners.
6. Install the floor: Lay the inner floor layer flat inside the tent. Position any growing trays, hydroponic reservoirs, or containers on top of it before introducing plants.
7. Route ducting and cables: Open the appropriate port covers and feed ducting through for your fan and filter combination. Use the adjustable port attachments to secure duct connections. Route power cords and sensor cables through separate port openings. Seal unused ports.
8. Install lighting: Hang your fixture from the roof cross-members using ratchet hangers. Start with the light at the upper position and lower it to the correct height once plants are introduced. Connect power outside the tent before running the cord in through a sealed port.
9. Test for light leaks: Turn off all room lights and run your grow lights inside the closed tent. Check all seams, zipper edges, and port covers from outside for any light bleed. Correct any gaps before beginning a photoperiod-sensitive grow.

Sources & Further Reading