Cannabis is a photoperiod responsive plant. It takes cues from the daylight fluctuations for triggering flowering and reproductive hormones. In the fall, as days get shorter, the plant is triggered to flower and produce seeds for next year’s new plants. We recreate this natural response when growing indoors by having more extended hours of light for vegetative growth and shorter hours of light to trigger blooming. 

  • During the vegetative light cycle, the photoperiod of 18/6 would mean the light is on for 18 hours and off for 6 hours.
  • During darkness, make sure there is no light leaking into your growing area.
  • During the flowering stage, have your lights on for 12 and off for 12 hours.
  • Put your lights on timers to precisely control your photoperiods. 
  • Some systems have built in sunrise/sunset and increasing/decreasing cycles.


indoor lighting

When growing indoors, there are choices in lighting, including metal halide, high-pressure sodium, LED, and others.  We have found that broad-spectrum LED’s have the best energy efficiency and thermal ratings for plant lighting. They also have the best photon to BTU ratio per watt of energy used. 


Not all LEDs (Light Emitting Diode) are equal. Most of the companies selling so-called “full-spectrum” LEDs are not full spectrum at all. Full-spectrum light means all the colors of light, in the same ratio’s as found in sunlight. Most of the low-cost LED lights are single hue blue, purple, and red diodes, and none of the colors in between. If you are using the wrong color spectrum during flower, you will notice a significant decrease in yield. There ARE, however, LEDs that use entirely different technology to reproduce a white light, which is much closer to natural sunlight (full-spectrum). Quality full-spectrum LED lights are about 10x more expensive than their cheaper alternatives. However, saving money on electricity is nice unless you are losing even more money due to a decrease in yield. Using the correct full-spectrum lights with Dyna-Gro will optimize your yields. 


outdoor lighting 

Depending on where you live, your growing season will vary. For example, in northern latitudes like Maine, most harvests must be finished by September 1st to miss the first frost. Whereas some places in California and Florida will not see the first frost until November or December, if they even see frost at all, affecting which strains can be grown outdoors. Your outdoor plants will start to flower mid-July, and depending on strain, can take between 8-14 weeks to finish. Hence, growing a 14-week strain in Maine would not allow the plant to finish safely before the frost. When selecting your strains, make sure that they will mature before the earliest expected frost.