Maximum Yield USA January 2017 | Page 104

SUPPLEMENTAL CO2 A good CO2 controller will essentially automate the CO2 system, controlling both the concentration (usually expressed in ppm) and the appropriate times for operation. Plants thrive in consistent environmental conditions and the concentration of CO2 is no exception. The amount of CO2 in the environment is detected by a ‘sniffer’, which will periodically sample the atmosphere’s concentration of CO2 and send a signal to the controller. If the concentration falls below the system’s set-point, the controller will then trigger the CO2 device to turn on. On the other hand, a good controller will stop the CO2 unit when exhaust fans are in operation so the CO2 is not being removed from the garden as soon as it is emitted. Newer, software-based control systems offer additional control features, such as remote access to the devices and data logging. Data logging of CO2 levels can provide valuable information over the course of a few garden cycles and can help a gardener determine the optimal concentration of CO2 for their particular crop. TEMPERATURE AND NUTRIENT REQUIREMENTS As previously mentioned, photosynthesis is a chemical reaction and, like other chemical reactions, it can be affected by temperature. A typical indoor garden 102 Maximum Yield USA  |  January 2017 will have an optimal temperature range of 70-80˚F. An indoor garden enriched with CO2 will have a slightly higher optimal temperature range (usually around 75-85˚F). It is also common for growers to increase the nutrient concentration in growrooms with increased CO2 levels. This makes perfect sense because if the rate of growth increases, the nutrient requirements will increase as well. Since nutrient requirements vary, there is no perfect way to tell the exact nutrient concentration needed. That being said, a grower can expect to increase his or her garden’s nutrient concentration " an indoor GARDEN ENRICHED WITH CO2 WILL HAVE A SLIGHTLY HIGHER OPTIMAL TEMPERATURE RANGE.� by five to 15 per cent when enriching the atmosphere with CO2. IN GENERAL Increasing the amount of CO2 in the atmosphere of an indoor garden or greenhouse can increase growth rates when all other factors are considered. This will not only equate to faster vegetative growth, but also larger yields. For some growers, increasing the rate of vegetative growth will allow them to start fruiting or flowering more quickly. A shorter vegetative cycle can mean more garden cycles per year and a more profitable garden. Growers who want to invest in CO2 equipment should go all-in. In order to reach the full potential of a CO2 enriched environment, growers will not only need equipment for creating the CO2, but also the adequate control devices to automate the system for efficiency. Without the full package, CO2 enrichment can be a disappointing venture with little gained in terms of overall financial investment. CO2 enrichment should be viewed as icing on the cake. In other words, CO2 systems should be something that growers add to an already fully functional and productive garden. The basics of lighting, ventilation, and nutrition should always be the first priorities for any indoor grower striving for success.