Also Know as the Gas Light Routine


We don’t care where the name came from but we do know that the GLR will save money on energy bills and encourage your plant to start flowering a little bit faster.

The GLR is only used for the vegetative cycle.

This light routine is a little different with three objectives:

  1. Giving the plant the light it needs for vigorous root and foliage development
  2. Save energy resulting in a lower energy bill
  3. Causes the plant to flower faster than any other light schedule

The GLR light schedule is as follows:

  • 12 hours of light on
  • 5.5 hours of light off
  • 1 hour of light on
  • 5.5 hours of light off

This results in running the lights for 13 hours each day resulting in a significant savings and when it comes time to start the flowering cycle, your buds will start forming quicker.

NOTE: some strains will flower using GLR so watch for that. If you do see the flowering cycle commence, just revert back to your regular vegetative hours.


12 Hours on7 PM - 7 AMAdjust listed times to your schedule
5.5 Hours off7 AM - 12:30 PM
1 Hour on12:30 PM - 1:30 PMThis one hour keeps plants in veg cycle
5.5 hours off1:30 PM - 7 PM


Some growers use a full 24 hours of light and others use 18 hours of light and 6 hours of darkness. On one hand, the grower is trying to mimic the summer daylight hours (18 on 6 off) while on the other hand the grower is trying to push their plants to grow  faster (24 on) with no rest or relief from the light.

We have tried both and see no advantage to running the lights 24 hours on. The plants look fine and the yields are similar what ever method you use. Of course running your lights for 24 hours will increase  your energy bill. Try the GLR and watch your energy bills drop.


Most growers use a 12 hours of light on and 12 hours off.

Other growers, including us start with 12 on and 12 off than every 2 weeks increase the off by 30 minutes trying to mimic the end of summer/fall sunlight.

Here is a flowering cycle lighting schedule we are following right now.


8.29-9-128 PM - 7 AMLights on
This column are dates7 AM - 8 PMLights off
9.12-9-268:30 PM - 7 AMLights on
7 AM - 8:30 PMLights off
9.26-10.109 PM - 7 AMLights on
7 AM - 9 PMLights off
10.10 - 10.249:30 PM - 7 AMLights on
7 AM - 9:30 PMLights off
10.24 - 11.710 PM - 7 AMLights on
7 AM - 10 PMLights off

    2 replies to "GLR Gas Light Routine"

Please leave your questions below to start a question and answer thread about your subject. I monitor the comments and will respond ASAP!

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Note to readers: If you purchase something through one of our affiliate links, we may earn a commission