Green Pad CO2 Generator, Pack of 5 pads w/2 hangers

The Green Pad CO2 Generator is a humidity-activated CO2 release system for indoor gardens. Each pack includes 5 pads and 2 hangers. Hang 1–2 pads above your plant canopy per 200–400 cubic feet of garden space. The pads absorb ambient humidity to trigger a natural chemical reaction that releases measured amounts of carbon dioxide — no tanks, regulators, or electrical connections required. Made in the USA by Hydrofarm.

Green Pad CO2 Generator Specifications

Key specifications for the Green Pad CO2 Generator, Pack of 5 pads with 2 hangers (SKU: GP6050), as sourced from the manufacturer’s product data.

Specification	Value
Brand	Hydrofarm (Green Pad)
SKU	GP6050
Pack Contents	5 CO2 pads and 2 wire hangers
CO2 Activation Method	Ambient humidity at 35% or higher; or light water misting; or moist sponge contact
Coverage per Pad	200–400 cubic feet (hang 1–2 pads per zone)
Recommended Placement	Above plant canopy
Replacement Schedule	Add new pad weekly; discard after 2 weeks of use
Pack Weight	0.5 lb
Country of Origin	Made in USA

Why Choose the Green Pad CO2 Generator

The Green Pad CO2 Generator addresses a straightforward problem: getting reliable CO2 supplementation into an indoor garden without investing in pressurized cylinders, regulators, solenoid valves, or CO2 controllers. The pad format lowers the barrier to entry and removes most of the maintenance overhead that comes with tank-based systems.

• No equipment to buy or maintain. The pads work through a natural humidity-driven chemical reaction. There is no pressurized tank to refill, no regulator to calibrate, and no electrical connection required. You hang a pad and the ambient moisture in your grow space does the rest.
• Humidity-activated chemistry. At 35% relative humidity or above — typical for most indoor grow rooms — the pad begins releasing CO2 without any manual intervention. You can also initiate activation more quickly by lightly misting the pad surface or folding a moist sponge inside the pad.
• Scalable coverage. Each pad is rated for 200–400 cubic feet. Running a larger tent or multi-light room? Add more pads proportionally. The system scales with your garden without any additional infrastructure.
• Useful as a tank backup. For growers already using CO2 cylinder systems, keeping a pack of Green Pads on hand provides a buffer if a tank runs empty or a refill is delayed. The pads have no expiration issues when stored, making them a low-cost insurance option.
• Made in the USA. The pads are manufactured domestically under the Hydrofarm brand, a US-based horticultural products company with an established distribution network.

Best Uses for the Green Pad CO2 Generator

The Green Pad CO2 Generator suits growers who want passive CO2 supplementation without equipment overhead. The following use cases reflect what the product is designed for, based on the manufacturer’s own application guidelines.

• Small to mid-sized sealed or semi-sealed grow tents. In a tent or small room where the ambient humidity stays at or above 35%, the pads activate reliably and continuously without adjustment. The 200–400 cubic foot per pad rating covers typical 2×4, 3×3, and 4×4 tent footprints at standard ceiling heights.
• Home hobbyist gardens seeking passive CO2. Growers who want to provide their plants with elevated CO2 levels — particularly during the vegetative and early flowering phases — can do so without learning to operate cylinder-based equipment or investing in a CO2 controller.
• Emergency CO2 backup for tank-based grows. If your primary CO2 cylinder runs empty between refills, hanging a Green Pad maintains some level of supplementation while you arrange a refill. The pads can be stored until needed without degrading.
• Gardens with good baseline humidity. In an environment where humidity control is already part of the grow setup and RH regularly sits at 35% or above, the pads activate consistently without manual misting. They are a natural fit alongside existing climate management equipment.
• Growers transitioning from no CO2 supplementation. The pads provide a low-commitment starting point for adding CO2 to a garden before deciding whether to invest in a full CO2 delivery system.

Green Pad CO2 Generator vs Similar CO2 Products

The main alternatives to humidity-activated CO2 pads are CO2 bags (mycological/fungal fermentation), pressurized CO2 cylinders with regulators, and CO2 burners (propane or natural gas combustion). Each has different cost, control, and complexity trade-offs.

vs CO2 bags (fungal fermentation): CO2 bags like the popular mushroom-based options activate through the CO2 produced by fungal metabolism. Both bags and pads are passive and equipment-free. The primary difference is activation: pads activate through humidity chemistry, while bags activate through temperature and moisture over a longer fermentation period. Pads have a defined two-week active window per pad and a predictable replacement schedule. Bags often have a longer but less consistent active period. For growers who want a shorter, more defined supplementation cycle, the pad format is more predictable.

vs CO2 cylinders with regulators: Cylinder systems give you precise, controllable CO2 delivery — especially when paired with a CO2 controller that manages dosing to a target PPM. The trade-off is cost and complexity: you need the cylinder, regulator, solenoid valve, tubing, and a controller or timer. The Green Pad asks none of that. Cylinders are appropriate when you need fine-grained PPM control or are supplementing CO2 in a large commercial space. The Green Pad is appropriate when a simpler, low-cost approach is sufficient.

vs CO2 burners: Propane or natural gas CO2 burners produce CO2 as a byproduct of combustion. They are typically used in large commercial greenhouses where heat generated by the burner is not a concern. In a sealed tent or small indoor garden, the additional heat and the requirement for proper ventilation and gas supply make burners impractical. The Green Pad has no heat output and no combustion risk.

Compatibility

The Green Pad CO2 Generator is compatible with any indoor garden where ambient relative humidity is reliably at or above 35%. No electrical connections, no plumbing, and no specific equipment pairings are required.

Grow tent compatibility: The pads work in any enclosed or semi-enclosed tent. A basic hook or the included wire hangers allow you to suspend them above the canopy from a tent crossbar or grow light rail. The pads work independently of your lighting setup, so they pair with HID, LED, or fluorescent systems without modification.

Ventilation considerations: The Green Pad is not intended for use in fully open, high-airflow spaces where CO2 would be immediately exhausted before reaching plants. In tents with active inline fans, run the fan on a schedule or reduce airflow during peak CO2 release periods to allow PPM levels to build. Using a pre-filter on your intake alongside controlled exhaust helps maintain the enclosed environment needed for the pads to be effective.

Humidity range: Activation begins at 35% RH. Standard vegetative and flowering humidity targets (40–70% RH) are well within this range. Growers running very low humidity environments (below 35%) may find activation inconsistent without supplemental misting.

Temperature: No specific temperature operating range is published by the manufacturer. The pads are designed for typical indoor garden environments. Extremes of heat or cold outside normal growing ranges may affect the chemical reaction rate, though no specific data is available from the canonical product documentation.

Usage Guidelines

The manufacturer’s guidance from the product description covers placement, activation, and replacement. Follow these guidelines to get consistent CO2 output from each pad.

Placement: Hang 1–2 pads above the plant canopy for every 200–400 cubic feet of garden space. Placement above the canopy (rather than below or at plant level) allows CO2, which is denser than air, to settle down through the canopy where stomata on leaf surfaces can absorb it.

Calculating how many pads you need: Measure your garden volume in cubic feet (length × width × height in feet). Divide by 300 (midpoint of the 200–400 range) to get a starting pad count. For a 4×4×8 ft tent (128 cubic feet), one pad is sufficient. For a 10×10×8 ft room (800 cubic feet), hang 2–4 pads distributed across the ceiling area. Adding more pads increases CO2 PPM in the space proportionally.

Activation: In a grow space at 35% RH or above, the pad activates passively once hung. To speed activation — useful when first setting up or if humidity is lower than usual — lightly mist the surface of the pad with water, or fold a damp sponge inside the pad. This provides the moisture the pad needs to begin its chemical reaction immediately.

Replacement: Add a new pad each week throughout your supplementation period. Each pad has a useful life of approximately two weeks; discard it after two weeks of use. Running overlapping pads on a weekly replacement schedule (hanging a new pad while the previous week’s pad finishes its second week) maintains a more consistent CO2 output level over time.

Storage: Unused pads store without expiration issues. Keep the pack sealed until use.

How to Set Up the Green Pad CO2 Generator

1. Calculate coverage needed. Measure your garden space in cubic feet (length × width × height). Divide by 200–400 to determine the number of pads required for your space. Start with 1 pad per 300 cubic feet as a baseline.
2. Attach the wire hangers. The pack includes 2 wire hangers. Thread or clip each hanger through the pad’s hanging point (hole or loop provided on the pad). These hangers are reusable across multiple pad replacements.
3. Hang above the plant canopy. Suspend the pad from a crossbar, tent pole, or light hanger at a height above the top of your plants. CO2 is heavier than air and will drift downward through the canopy after release. Distribute multiple pads evenly across the ceiling area of larger spaces.
4. Confirm humidity or initiate activation. Check your grow space’s relative humidity. If it is at or above 35%, the pad will begin activating passively. If humidity is below 35% or you want immediate activation, lightly mist the pad surface with water or place a damp sponge in contact with the pad.
5. Monitor and maintain a weekly replacement schedule. Mark the installation date on each pad or set a weekly reminder. Add a fresh pad each week. Remove and discard any pad that has been in use for two weeks.
6. Scale up as needed. If you want to increase CO2 PPM, add additional pads. More pads in the same space directly increases the CO2 output in that zone.

Sources & Further Reading