The Light Cycle Debate

Another great article!! During my limited time growing indoors I have experimented with what I consider to be the 3 most common vegetative light cycles (18/6,20/4,24/0) for photoperiod plants and my experience has been on par with what you have written here. What I have found is that plants in my garden require 675-700 kWh of light to reach the growth that I desire before the flowering cycle. I have been able to achieve this growth in 28-30 days with a 24/0 light cycle, 34-38 days with a 20/4 light cycle, and 37-42 days with a 18/6 light cycle. In all 3 cases the difference in kWh used is marginal when taken in the context of the entire grow but growing a receptive plant under 24/0 vs.18/6 could save as much as 14 days of vegetative time . I personally want to make the switch to 12/12 as quickly as possible with photoperiod plants because the longer light cycle of the vegetative stage is the most costly. Having said that, I don't think you can simply compare the cost of light cycles when addressing Auto- flowers due to their need for increased light in order to maximize yield. While I agree that the increased yield of a 24/0 light cycle for an Auto-flower comes at the expense of increased cost, if compared to a photoperiod grow of the same yield the cost increase is almost negligible due to their overall rapid maturation rates. I can have a photoperiod plant in the vegetative stage for 28 days @ 24/0(672kWh) and flowering cycle for 70 days @ 12/12(840kWh) for a total of 1512 kWh used while an Auto-flower that matures in 60 days under 24/0 uses a total of 1440 kWh.

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