i have used 16/8 the whole time. i was under the impression it takes about 8 hours to complete photosynthesis.
I use 18/6, but I'm sure they all work well. The only reason I would shy away from 24/0 is because plants do very important things during the night cycle. And if you deny them this, there is a much higher chance of shock when you eventually introduce a night cycle to them. It's nature after all... you have to keep some of the rules in play. I'm sure 24/0 is very good for rooting though.
"This is a direct quote from Ed Rosenthal whom most of you know is a marijuana growing guru: Marijuana plants photosynthesize as long as they receive light as well as water, air, nutrients and suitable temperature. Photosynthesis is the process in which plants use the energy from light (primarily in the blue and red spectrum's) to combine carbon dioxide (CO2) from the air and water (H2O) to make sugar while releasing oxygen to the air. Plants use sugars continuously to fuel metabolic processes (living) as well as for tissue building. The plant combines nitrogen (N) with the sugar to make amino acids, the building blocks of proteins. They are the substance of plant tissue. When the light is off, the plant's metabolic processes, respiration and growth, continue. The plant can photosynthesize continuously so it produces the most energy and growth when the light is on, continuously. Continuous light does not stress the plant, which reacts somewhat mechanistically to it. Plants under an 18-6 light-dark regimen are producing sugar only three quarters of the time. They are thus growing at only 75% of their potential. Leaving the light on continuously will result in bigger plants, faster, which leads to higher yields." ------------------------------------------------------------- "The following information is straight from Greg Green's "The Cannabis Grow Bible" Cannabis is a light demanding plant. Professional growers keep the light on their plants using the 24/0 photoperiod for this reason. Plants that grow under 24/0 flourish and do not need a quantity of darkness in order to rest and perform photosynthesis properly. Plants that are grown in optimal conditions under 24/0 light regime grow vigorusly and the benefits of a 24/0 photoperiod can be seen actively in the results. More nodes are formed, more branches are created, leaf numbers increase, the plant is growing at its finest. Some growers opt to use 18/6 as their photoperiod. This is 18 hours of light, six hours of darkness light regime. Under these conditions the plant will grow quite naturally but not as vigorously as the 24/0 photoperiod. The 18/6 photoperiod expels 3/4 the amount of light that a 24/0 photoperiod does. Although this does not mean that a plant produces 1/4 less leaves,branches and nodes under the 18/6 photoperiod, it certainly does show the correlation between light and cannabis growth. As we have said already, cannabis is a light demanding plant. There are no problems associated with 24/0 and although some have attributed cannabis sexual dysfunction (the hermaphrodite conditon) to 18/6 photoperiod these problems are actually the result of heat stress. A 24/0 photoperiod requires that your grow room temperature be kept well monitored. The 18/6 option is cheaper to run. You use a quarter less electricity and this will have an impact on your electricity bill. Also the 18/6 photoperiod will generally extend the bulb's lifespan. During the 6 hours of darkness the grow room is allowed to cool down for this period but a well maintained good grow room setup should not require a cooling down period. 24/0 and 18/6 both share the same problem though. Once you start the photoperiod you should keep that way especially when the plants near maturity (the preflowering stage). An irregular photoperiod can cause more males than females to develop. It can also cause sexual dysfunction to appear. Whether you choose 24/0 or 18/6 as your vegetative photoperiod try to keep that photoperiod unitl your plants are mature enough to express their sex." TLDR: 24/0 is superior insofar as plant growth
Great response. I may try out that 24/0 thing as I veg with a 400w MH and Florotubes. The extra 6 hours of elecitricity should be nill.
From what I've read 24 hr light will give you the best results. But you get exponentially smaller return on investment. So is it worth it for the extra risk in electric bill / money of the bill?... Meaning 24 hour light (compared to 20 hour light) is going to cost you 20% more but you'll be lucky to see a 5% difference in yield. My buddy does 20 hours and gets really good results.
Not trying to improve yield, trying to quicken vegetive growth. If i can cut two weeks off off vegging that would be ideal.
The only reason I can see for 18/6 during veg, is to reduce heat. I don't think theres any other reason not to go 24/0
yeah but during the day my temp is going up to 100 degrees, at night when the lights are on its a cool 75-80 tops... im turnin the lights off from like 12-6 my plants are growing very well tho they are very green and healthy and growing at a faster than normal pace, ive been looking at peoples stuff from like 9 or 10 days and mine are on like 4 should i alter everything or just keep as is?
If your plants don't appear to be struggling, let them do their thing. That's my advice, let your plant tell you what it needs
Hottest part of the day is between 11am - 2pm, might help on temp to set that schedule back just an hour or two
Yea, in your case you should prolly do 18/6 then if temp is a problem, but if possible get some exhaust and try an AC, keep your temp regulated.