Does the 12-1 Lighting Method Increase Yield and Potency?

An increasing number of states are allowing MMJ patients to grow their own weed at home. Producing a few plants can be a cheaper option if you live far from your nearest dispensary. However, cannabis can be a tricky plant to grow.

Each strain has its own particularities. It’s a good idea to read up on the strain you’re trying to grow; here at WayofLeaf, we have tons of guides on cannabis cultivation, including instructions and tips for specific strains.

Even when armed with these guides, however, we recommend having a little general knowledge behind you. One thing you should be clued up on is lighting. Indoor growers require a way to control the lighting in their grow room, encouraging their cannabis plants to enter particular stages of the life cycle.

Recently, the 12/1 lighting method has gained some notoriety, but is it really the best method? In this brief rundown, we explain the 12-1 lighting method and give you some crucial information.

What Is the 12-1 Lighting Method?

If you know anything about lighting, you might be a bit puzzled. Many growers recommend an 18-6 lighting method, in which you leave the lights on for eighteen hours and switch them off for six. Eighteen plus six is twenty-four, covering all 24 hours in a day.


But twelve plus one is… thirteen. What about all the other hours? The 12/1 lighting method is actually as follows:

  • 12 hours of light
  • 5.5 hours of no light
  • 1 hour of light
  • 5.5 hours of no light
  • Repeat

This way, you cover the full day. Proponents argue that this method is better during the vegetative stage of growth. Some believe that the 18-6 lighting method has surged to popularity through some sort of conspiracy theory, but we won’t go into that here! Let’s stick to some of the reasons why the 12/1 lighting method is a good idea.

Benefits of the 12-1 Lighting Method

There is actually a third method of marijuana growing: The 24/0 method. This technique involves having your lights switched on for the whole day, with no dark periods. Not only will this land you with a high energy bill, but it’s also bad for your plants!

Think about it. Cannabis is a naturally occurring plant. When it evolved in the wild, it grew in places with light and dark periods. Plants use the night-time, when it’s dark, to utilize the energy they generate from photosynthesis during the day. This makes dark periods vital to their growth.

While 18/6 is a better method, advocates of the 12-1 lighting scheme argue that it’s more natural. Plus, you save tons of energy! Some internet estimates guess that you could save 30–50% on your energy costs by using this method.

Other growers have argued that they have seen better results and higher yields when using the 12/1 method rather than the 18/6 process.

At the end of the day, it might take a little trial and error to figure out what works best for you and your favorite strain. However, due to the savings that you make in energy costs, giving the 12-1 method a shot is definitely worth it!

When Should I Use 12-1 Lighting for My Cannabis?

Although the 12-1 lighting method is excellent, you can’t run for the entire lifespan of your cannabis plant. If you do, it will never flower! Wasting time in the vegetative stage is not ideal because you never get to reap the rewards of your work.

12-1 lighting is excellent for the vegetative stage, but you need to switch it up as your plants reach maturity. When you want to begin flowering, change the lighting schedule as follows:

  1. Switch to 11 hours on and 13 hours off.
  2. Two weeks later, decrease the light period by half an hour. In other words, 10.5 hours on and 13.5 hours in darkness.
  3. Do this every two weeks, reducing the lighting period by 30 minutes and increasing the dark period by 30 minutes.
  4. When you hit 9 hours on and 15 hours off, your plants should be ready to harvest.

Remember, each strain is different and has a varying flowering time. As a result, you need to pay careful attention to your crop to get the best yields.

Choosing the Right Lights for Your Grow Room

None of this information is worth it if you’re using the wrong lights! There are plenty of options for marijuana growers, but the three most common are HID, CFL, and LED. Here’s a quick summary of each:

  • High-Intensity Discharge (HID): This old-school lighting has been used for decades. Since it’s older, it tends to be less energy efficient. New HIDs are a bit better, but they’re not the best option.
  • Ceramic Metal-Halide (CMH): Although expensive, CMH or CFL lighting is ideal for smaller spaces because it gives off less heat. If you have a tiny grow room, consider CFLs.
  • Light-Emitting Diode (LED): Nowadays, LEDs are probably the most common form of lighting. LEDs are cost-effective and don’t get too hot. Plus, they are really energy-efficient, which spells good news for your bills.

LEDs grow plants a little slower, which makes them ideal for the 12-1 lighting method. Many marijuana cultivators favor LEDs these days for a variety of reasons. This would be our number one choice for indoor growing.

However, CFLs can be a better and safer option if you have a super small grow room. You have to take heat into account, so be careful.

Final Thoughts on the 12-1 Lighting Method

If you ask any advocate of the 12-1 lighting method why it hasn’t taken off, be prepared for a long rant about other lighting techniques. Proponents of this method argue that it is much more cost-effective and better for your cannabis plants.

At the end of the day, growers find success using a variety of different techniques. There are lots of benefits to 12-1 lighting, but the only way to find out if it works for you is to try it. Considering the energy savings you could make, we encourage you to give it a shot!

Have you tried the 12-1 method before? How did it go? Let us know your opinions on the 12-1 lighting method in the comments.

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