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Sunday, April 21, 2024 Matt D. Connecticut

Entry 18 of 116  
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Supplemental CMH Light (Part 1 of 2)

The green timer is attached to the 315-watt CMH (Ceramic Metal Halide) grow light with a 4200K daylight bulb in it. This comes on at 4am then off at 9am and then back on at 6pm and off at 10pm. This serves two important tasks…

1.    It adds light to increase the plants perceived photo period to replicate late June. This not only helps with speeding up the plant growth rate, but also allows the CO2 to be added for a longer period of time since there is a photo sensor on the sensor that will only add CO2 when there is enough light that the plants can use CO2, since it cannot be utilize during the “night” or dark portion of the day.

2.    Most growers will wonder why LED lights are not being used, why has a CMH light been selected? This is because CMH will generate more heat and can be spaced higher from the plant to increase coverage area and allow more natural sun to reach the plant when the light is off during the day. The heat is a good thing early in the season and the more heat the better as this can warm the leaf up also increasing the photosynthetic rate making extra use of the elevated CO2 levels. Also, the increase in spacing from light fixture to plant is nice so there is less shade during the day when the sun is out and the artificial light is off.

YouTube Video Link “CMH Lighting Option” : YouTube
 



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