You are hereSo I'm growing an auto-flowering cannabis strain, what is the best light schedule?

So I'm growing an auto-flowering cannabis strain, what is the best light schedule?


Most strains of marijuana rely on the amount of light, or their light schedule, to determine whether to spend energy on growing or making buds. Generally, if a marijuana plant receives 14 hours of light a day or more, than it will focus more on growing bigger instead of producing buds.

This is called the vegetative stage. If the plant receives 12-13 hours of light a day or less, it will switch to the flowering stage and start focusing more of its energy on creating buds. This happens naturally outside when the seasons change and days get shorter. Fflowering can also be artificially induced by changing the light schedule when growing indoors.

(Have questions about buying cannabis seeds online?)

Lowryders or "Auto-Flowering" varieties of cannabis have different light requirements

Auto-flowering strains of marijuana don't rely on a change in light schedule to determine when to flower. These strains (the most common strain is called "Lowryder") will finish their whole life cycle in two to three months, regardless of how much light they receive a day. The next question, then, is how much light to give auto-flowering or Lowryder marijuana plants if you are growing indoors? 

Most people seem to agree that the optimum amount of light to give is 18-24 hours of light a day for auto-flowering strains of marijuana. I have spoken with two people who have grown Lowryders personally and they have both told me that their auto-flowering plants seemed to do best when given 18 hours of light a day (as opposed to 24 hours a day). They both said that their plant's leaves seemed to be more green and healthy looking when given a 6 hour "dark period" every day. This obviously isn't a large sampling of people, but from what I've read on forums online, there does seem to be a general consensus among experienced Lowryder growers that 18 hours of light a day is best for auto-flowering strains. 

In contrast, many in-the-know people (such as Jorge Cervantes, who wrote  Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible) seem to agree that regular indica and sativa strains of marijuana get the most growth if given 24 hours of light a day when in the vegetative stage. I know that when I am growing indica, sativa, or hybrid strains of marijuana, I give them 24 hours of light a day during the vegetative stage and get great results!

Light Spectrum

Another consideration when growing auto-flowering plants is what light spectrum to use. Normally you would optimally use more 6500k (blue) lights for the vegetative period and more 2700k (red) lights for your plant during the flowering period. With Lowryders, follow the same principle by using the 6500k lights before the plant has showed signs of it's gender, and then switch to more 2700k lights once you see the first signs of gender.

However, marijuana plants are weeds, and will usually grow at least okay under either spectrum of light during either stage. For the hobbyist grower who may be low on cash and can't change up the lights, your best bet would be to get a few of both types of light for the whole grow. You may want to get a slightly higher percentage of 2700k lights since your plant will be bigger during the flowering stage and therefore need more light coverage than when it's younger and in the vegetative stage.

If you have any thoughts or opinions about light schedules and light spectrums, for any sort of marijuana strain including auto-flowering, I'd love to hear about your experiences!