Grow room and indoor greenhouse growers agree that for optimum plant growth, you should enrich the air around the plants with carbon dioxide(CO2) during the daylight growth cycle. Photosynthesis (plant growth) requires light, water, and nutrients, the limiting factor in their growth will be the amount of CO2 in the air.

While normal outdoor CO2 levels (about 400ppm) will achieve normal plant growth, doubling or tripinling the CO2 levels can increase the growth rate. However, above 2,000ppm CO2 becomes toxic to plants, and above 5,000ppm CO2 becomes potentially harmful to people. Most experts agree that 1,500ppm is the maximum CO2 level for maximum plant growth, althouth any CO2 level between 1,000 and 1,500 ppm will produce greatly improved results.

 

CO2 Grow Room Calculation

To calculate the amount of CO2 you need, you’ll need to calculate the size of the grow room. For example, if you have a 8x8x7 feet grow room, you would need to cover 448 cubic feet (8x8x7=448). To compute the amount of CO2 required to raise the level to 1,000 ppm use this equation:

 

Width x length x height x desired CO2 level in parts per million

So in our example, we have 8x8x7x0.001 =0.448 cubic feet of CO2 needed to raise the level inside the grow room to 1,000ppm CO2.

 We can roughly calculate how long the regulator will be turned on with this formula:

 

CO2 needed in cu.ft. / flow rate per minute

 Since we need 0.448 cu.ft and the regulator is set at 0.08 cu.ft. per minute, the CO2 Controller will activate the solenoid on the regualtor for approximately 5.6 minutes to raise the CO2 level to 1,000ppm(0.448/0.08).

 

CO2 Calculation Tips

Experts disagree about the optimum level of CO2 for plant growth. You can find arguments for 800ppm, 1,000ppm, 1,200ppm and 1,500ppm. We recommend starting at 1,000pppm, then adjusting your CO2 levels over time with experience. CO2 levels below 400ppm and above 1,500ppm will reduce plant growth.

 

Experts do agree that raising CO2 alone will not guarantee plant growth. Proper soil, nutrients, watering, light and cleanliness must be achieved in combination with enhance CO2 level for optimum results.

 A fan inside the grow area pointed at the end of a length of tubing from the regulator will circulate the CO2 in the air for maximum benefit. Otherwise, you can connect the regulator to a length of tubing with pin-holes strung around the top of the grow room so that the CO2 will “drop” on the pants (CO2 is heavier than air).

 If you are growing indoors, purchase an inexpensive timer to control your day/night light period. Never run CO2 during the dark period.

 Not the temperature on the indoor CO2 Grow Controller temperatures above 27°C (80°F)
over time can result in enlongated stems and lower yields of mature plants.