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How To Use The 12/1 Lighting Method For Efficient Marijuana Cultivation


Marijuana PlantBy Dennis Ford

I’d like to talk about a subject you will here about often on Cannabis Dynamics. The 12/1 lighting method.

The 12/1 is a very simple concept, but for some reason has been very hard to catch on. People just don’t believe its that easy or that it works as well as it does.

In a standard lighting scheme, we have all come to believe in basically one or two camps. I won’t get into who’s behind the whole “conspiracy” of keeping 12/1 out of the masses, but if you want to hear some good shit please see John P. RN (you know who!) or Joseph Pietri on Facebook. There are some interesting stories, but the truth is the current methods that 99% of growers use create a very telltale footprint for LEO to follow if they begin to suspect you.

I’ve found that for veg growth there are the two camps of 18/6 and 24/0 (18 hours of light and 6 hours of darkness, this is not how 12/1 works though, that will be explained below). The fact is that all plants need a darkness period to process the days energy into food and growth. Therefore your doing yourself absolutely no favors using a 24/0 for anything other than cloning. All you have to do is look outside, there are only 2 places on earth that ever get 24 hour light at any point, and you aren’t going to find ANYTHING growing there. Cloning of course is not of nature, we are tricking nature, so we put the plant into a constant light period to facilitate this. We’ll talk a lot more about cloning someday in another post. 18/6 works on the other hand, but the truth is your wasting light. Its time to wake up! Its time to trick nature again!

Truth is you really only need to break up the photosynthesis dark period with an hour of light to maintain veg, and in doing so you give the little lady a massive darkness processing/growth period. 12/1 is simply 12 hours on, 5.5 hours off, 1 hour on, and 5.5 hours off. Then repeat through your entire veg period.


12 hours ON, 5.5 hours OFF, 1 hour ON, and 5.5 hours OFF for each 24 hour period.

This is only for VEGETATIVE PERIOD, we have another simple process to follow for flowering.

We are also not going to discuss nutrients or tea’s just yet either. Those will be other posts coming soon.

For vegetation, this is all you need to know lighting wise. Trust me, I was skeptical at first too, but John P. RN really convinced me after spending a couple years of listening to Joseph Pietri to try it. It worked great for him, and now it works great for me.

One of the obvious first things you’ll see is a significant drop in your power bill. Who doesn’t love that? But also your doing one other thing, breaking up the light period to prevent a multi-year footprint that LEO might find matches footprints they are looking for.


Flowering is simple as well, but its important during this delicate period in a plants life cycle to follow as closely what the evolution of the plant is looking for. Veg is different, the plant just wants to grow as big and lovely as it can. During flowering the plant is following a very specific genetic code for its conduct to continue the propagation of its species. This is why we adjust our lighting every 2 weeks.

When we begin flowering, move everything to 11 hours on, and 13 hours off. You will keep this for 2 weeks, then drop the lighting period by 30 minutes, I.E. after two weeks you will switch to 10.5 hours on, and 13.5 hours off. Continue this 30 minute drop every 2 weeks until you reach 9 hours on/ 15 hours off. Finish your flowering at this lighting.

Trust me, have a look at some of the pics below. These plants were all grown, in the various stages you see here, using these methods.

12/1 works people, save yourself some money, and maybe just save your ass!

Dennis Ford, Cannabis Dynamics

Big thank you to John P. RN and Joseph Pietri!

12/1 Lighting For Marijuana Cultivation

12/1 lighting method for marijuana cultivation

12/1 lighting method for marijuana cultivation

Article From cannabisdynamics.com


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  1. I have been using 12 1 lighting for years…they actually grow faster with two naps. Flower starting at 11 too. No problem. Healtjy vigorous plants. Saves a buck, been my experience. You can’t argue with plant physiology.Eh? Hope my experience helps.Peace

  2. P.S. Not surprising the guy who wrote this is the same one that posted about “push pop pipe” and suggesting people use flimsy plastic right near a hot bowl you are smoking out of.

  3. First of all, calling this 12/1 is stupid. Second of all, I have no doubt this works in Veg, but your Flowering times are suspect, confirmed by the fact that you only provide pics of your plants in Veg and give no evidence that your flowering times are efficient. Yes the plants will finish earlier, with less yield. Nothing here suggests it’s worth doing in Flower and all evidence points to the fact that 11.5.

    This suggestion should only be considered if you are growing a sativa-dominant strain that you want to finish earlier than usual…otherwise you are just limiting the amount of energy the plant can use by shortening the light cycles more than needed to trigger flowering.

  4. I used to race and breed pigeons and we would manipulate the light/dark to keep the birds from molting or force them to molt early. Most guys would try and turn lights on early in the am or build expensive lofts to that they could darken them and shorten the day. I always used a technique similar to the 12/1 you described and it worked wonders on manipulating the birds molt.

  5. Hello, I recently saw an article that discusses the 12-1 vegging technique with a twist. As opposed to having the lights on for 12 hours straight, the author stated they had a 30 min on 30 min off for 12 hours, with the same 5.5 then 1 hour on 5.5 off. I’m currently giving it a try and will report back. I had a concern that I’m doing this with seedlings and am wondering if this would ‘stress” the plants to predominantly show males? I guess we’ll see. I would think this technique would be good with clones only as there wouldn’t be a sexing issue. Any thoughts ……

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