How many hours of light are needed for vegative growth and why do you think so?

When asked how much light do you give your plants for vegative cycles you may get many different answers. When asked why or how they learned of their choice answers get a little fuzzy. The most common answer is hours on and 6 hours off in a hour cycle... yes there are other cycles but that's for later. Also a very popular technique is 23 hours of light allegedly giving the plants the maximum amount of light, or even 24 hours of solid light in some cases. What's the difference? Well, 5 to 11 hours of electricity to start. Since power costs are one of if not THE biggest out of pocket expenses why keep giving it to the power company? Because you read it in a book? Because somebody told you? Perhaps you are of the mind "it works great for me why wouldn't I?" A common mistake of logic. If you don't know a plant's potential, you will never realize it.


To understand what is required for a plant to have vegative growth we first have to know what makes it flower.


Most cannabis requires 12 hours of uninterrupted darkness. This happens with a on off light schedule in indoor grows, in the late summer/fall of the U.S. and Canada and nearly year round in Hawaii. Most everyone knows this already but did you know that Cannabis grows at night? The plant photosynthesizes light, water and CO2 into sugars in the daytime and "eats" those sugars at night when it does most of it's actual growing. So, if your plants get 6 hours of darkness they get 6 hours to grow, much less with a 23-24 hour light schedule. Yes, they also grow in the daytime but not nearly as much. Resin production is also at night as it "burns off" during the day by the sun or lights. That's why is best to harvest pre- dawn or as early in the morning as possible.


The only thing needed to grow vegatively is an interruption in the dark cycle. That is it.


If a simple interruption in the dark cycle is all that is needed then the question is how much light and when? This is an elementary question in horticulture. In fact, this whole technique is Horticulture 101 and the fact that people have been wasting money, time and yield for decades not knowing why lends to the term "zombie growers". Mindlessly throwing away money like in a daze or stupor. 18/6 is not the best way to veg plants. What is the best or nearly perfect is 12/1. The schedule goes like this:


12 hours of light/sun

5.5 hours of darkness

1 hour of light

5.5 hours of darkness


First of all notice the 2-5.5 hour periods of darkness as opposed to only the one in a 18/6 cycle. This gives your plants almost twice the time to grow resulting in bigger plants. Since you will have your lights come on for only one hours in the middle of the night you will be saving over 30% on your power bill and that savings will add up. Why only an hour or why that long? That is a very good question that can be answered this way. It is a combination of intensity and time. The more powerful the light source the less time is need to erase the hormone buildup that occurs in darkness. Once certain plant hormones reach certain levels the plant switches on flowering mode. These are photosensitive hormones that are destroyed by light hence the interruption with one hour of light. Some growers swear by as little as 15 minutes of light and the University of Oklahoma did an experiment with large greenhouses of Chrysanthemums that have the same photoperiod as Cannabis or Poinsettias. The plants were exposed to very powerful strobe lights for only one very fast flash in the middle of the night. We're talking a fraction of a second of super bright light. No plants showed any signs of flowering.


12/1 will save money on power, grow bigger plants and hasten flower times for larger yields in the end. If you are a commercial grower of growing for the traditional market you are wasting money everyday you do not switch to 12/1. If you grow 18/6 or 23 or 24 hour schedules and don't switch you are a zombie grower. For many of you this is the best information you have ever learned about growing so please pass it along to everyone and don't stop. Share this article, spread the link...open dialog on social media. Do experiments of your own and post results. This isn't new....this isn't hype...this is Horticulture 101.


Mahalo for taking the time to learn more about growing....don't forget, the first and most important single thing you can do to grow the kind of herb you will love (the best) is "Strain Selection". Hawaiian is some of the very best on Earth and the spot to find these genetics is Big Island Genetics, the sponsor of this blog. Please feel free to read more from the Professor and checkout the seed shop where most seeds come with a free T-shirt too (or other way around) https://www.bigislandgenetics.org/shop


BLOG15OFF coupon code- use at checkout for 15% off ALL SEEDS!


Professor Potgrower



Featured Posts
No posts published in this language yet
Stay tuned...
Recent Posts