MY : How much do your supplemental lights really have to work ?
MATT : We have 20 DE lights in a 30x96-foot greenhouse that we use during both the vegetative and flowering cycles . During the veg phase , we run the lights from 4 p . m . until 1 a . m . to provide 18 hours of light during the short winter days ( currently the sun rises at 7 a . m . and sets at 4:45 p . m .). Once we reach flower , we use our lights only on cloudy days . But , when it ’ s sunny , like it is most days in California , we don ’ t need to turn the lights on at all because the short days trigger the 12 / 12 photoperiod . So I ’ d say , during flower , we use the lights on one-third ( 33 per cent ) of the days .
When it ’ s sunny , like it is most days in California , we don ’ t need to turn the lights on at all because the short days trigger the 12 / 12 photoperiod .”
MY : What are your estimates on power savings when compared to traditional indoor growing ?
MATT : You have to consider the size of your canopy against what you are paying in electric bills . It ’ s tough to give an exact figure because the amount of time we use our lights ( during flower ) is totally dependent upon the weather . However , our canopy is 1,720 square feet ( 86x20 ) with 20,000W in electricity . When you compare this figure against an indoor operation canopy at 400 square feet ( 20x20 ) and 16,000W of electricity , the savings per square foot are already quite evident , even during vegetative growth . When it comes time to flower and we only run the lights one-third of the days , the savings are astronomical .