CO2 Generator by The Green Pad — Humidity Activated CO2 Pads
GPJR
Humidity-activated CO2 pads that enrich a sealed tent or grow room with no tank, regulator or burner. Junior for domes and clone tents, Original for 200-400 cu ft, Grand Daddy for 800 cu ft per pad.
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Pairs well with
The Green Pad is CO2 enrichment without the hardware. Each pad is a layered sheet of natural carbons and acids that reacts with the moisture already in your grow space — hang it up, and once humidity passes about 35% it starts releasing CO2 on its own. No cylinder, no regulator, no solenoid, no gas line, and no burner adding heat and water vapour to a room you are already trying to control. Three sizes cover everything from a propagation dome to a full grow room: Junior for cuttings and seedlings, Original for small tents, and the Grand Daddy for larger sealed spaces. Made in the USA.
Specifications
Grower's Tip
- Seal the space or do not bother. CO2 enrichment of any kind only works in a room that holds air. If your extraction is running continuously you are pulling the CO2 straight back out — run the pads while the tent is closed, or put your inline on a controller.
- This is why pads and clone tents go so well together. A sealed propagation tent is already warm and humid, which is exactly the condition a pad needs to activate, and there is no fan fighting you.
- Hang it above the canopy, not beside it. CO2 is heavier than air and settles downward, so the pad wants to be over the plants rather than on the floor next to them.
- A light mist gets a pad going faster if your room is drier than it likes. Do not soak it — you are triggering a reaction, not washing it.
- Stagger your replacements rather than swapping everything at once. Original pads peak at the end of week one, so adding a fresh pad partway through keeps the output steadier than a hard changeover.
- CO2 displaces oxygen. In any sealed room you are enriching, air it out before you spend real time working in there — basic practice, and worth the habit.
Which Pad Do I Need?
How To Use
Pairs Well With
A sealed 0.75 x 0.5 x 0.7m propagation tent. Warm, humid and closed — the ideal home for a Junior pad.
Clone Tent Propagation KitTent, LED bar, heat mat, humidifier and a 10-pack of Juniors bundled together at a saving.
Humidity ControlThe pads run on humidity. A humidifier and a decent hygrometer make the whole thing predictable.
Environment ControlFan controllers and timers so your extraction cycles instead of running flat out and venting your CO2.
All CO2 GeneratorsThe rest of the CO2 range if you have outgrown pads and want a regulated system.
Propagation GearDomes, trays and plugs — the setup a Junior pad was designed to sit inside.
Frequently Asked Questions
How does a pad actually make CO2?
It is a layered sheet of natural carbons and acids. Moisture from the air is the trigger — once ambient humidity reaches roughly 35%, the layers begin reacting and release carbon dioxide steadily as the pad works through itself. There is no power, no combustion and no moving parts involved. A light misting speeds the reaction up if your room is on the dry side.
Do I need to seal my tent for this to work?
Effectively, yes — and that applies to every form of CO2 enrichment, not just pads. If an extraction fan is running continuously it removes the enriched air about as fast as the pad can produce it. Run the pads with the space closed, or put your inline fan on a controller or timer so it cycles rather than runs flat out. This is exactly why pads suit sealed clone tents and propagation domes so well.
Which size do I need for my space?
Junior is for humidity domes, cloners and clone tents — it sits inside with the cuttings. Original covers 200 to 400 cubic feet on one to two pads, which suits most single grow tents. Grand Daddy covers 800 cubic feet per pad with the output of four or more Originals, for grow rooms. Work out your volume in cubic feet first: length by width by height, or multiply cubic metres by about 35.
How long does a pad last?
It depends on the size. A Junior in a propagation dome is swapped every other day until the cuttings root. An Original runs about two weeks and peaks at the end of the first week, so the manufacturer's guidance is to add a fresh pad weekly. A Grand Daddy gets a fresh pad added every 10 to 12 days, with older pads left in place for up to 20 days.
Do unused pads go off in storage?
No. The pads stay dormant until they are exposed to humidity, so an unopened pack is not on a countdown the way a mixed nutrient or a compressed gas cylinder is. Keep them sealed and dry and take out only the pads you are putting to work.
Where should I hang the pad?
Above the canopy. CO2 is heavier than air and drifts downward, so a pad hung over the plants puts the gas where it can settle through the leaves. Original packs include two hangers and Grand Daddy packs include one. Juniors do not need a hanger — they simply sit inside the dome or tent with the cuttings.
Is it safe to be in the room?
Pads are a passive, low-output source with no flame, no fuel and no pressurised gas, which makes them the mildest CO2 option available. That said, carbon dioxide displaces oxygen in any enclosed space, so treat an enriched sealed room the way you would treat any of them: open it up and let it air before you spend an extended stretch working in there.
Select Pack Size
CO2 Without The Cylinder
Pick the pack that matches your space and hang it up. Free shipping over $499*.
