In nature, cannabis plants (excluding ruderalis) begin to flower in the late Summer and early Fall. When the days start to become shorter and the nights longer, flowering signals are triggered by photoperiodism, beginning the flowering process. The increasing hours of darkness signal to the plant that Fall is just around the corner. The female marijuana plant shifts its energy from vegetative growth into flowering, in order to attract pollen and produce seeds. Â By manipulating the hours of darkness, indoor and outdoor growers can delay flowering indefinitely or begin flowering whenever desired.
The traditional method used to sustain vegetative growth is to keep light on the plants between 18 and 24 hours each day. The key factor is not the hours of light, but the hours of darkness. With six hours of darkness or less, the plants will continue to put on vegetative growth as if they were experiencing an extended Summer.
When it is deemed time for the flowering process to begin, the light cycle is changed to a regimen of 12 hour on and 12 hours off. Â The increasing hours of uninterrupted darkness cause the plants to respond as if Autumn is approaching, and begin to flower. By using these two light cycles, you can control when your plants flower.
Over the years I have taught a few people how to grow cannabis. In doing so, I have learned a few lessons myself. Simply telling someone what to do is generally not enough. Unless I also explain the reasons behind the practice, it is usually only a matter of time before they forget or decide to change things up. It also seems to be a lot easier for growers to diagnose their own problems when they have a firm grip on the reasons plants grow how they do.
The Science in Layman’s Terms
Cannabis plants are referred to as long night or short day plants, because they require a long period of darkness to trigger the hormones that tell the plant to switch from vegetative growth to flowering. These light receptors are color pigments in the leaves called Phytochrome Red (PR) and Phytochrome Far Red (PFR). These pigments get their names from the types of light they absorb. PR absorbs red light between 660 and 760 nm and PFR absorbs far red light between 760 and 800 nm. These two pigments chemically react to the light, and trigger the plant to flower or not.
This is where it gets a little confusing.
In cannabis plants, the normal presence of PFR switches off the flowering signal.  The level of PFR is what you can manipulate by adjusting the photoperiod.  PFR is quickly produced when plants are exposed to light that contains far red wavelengths. When there is light, the PFR and PR maintain a balance. When the sun goes down or the lights go out, the darkness gradually switches the PFR to PR. Because of this, PR levels gradually increase and the PFR gradually decrease during the dark period. The presence of PR is a neutral condition to the plants and essentially tells them nothing. When the light returns, or if a small amount of far red light interrupts the dark period, the PR immediately switches back to PFR. If the plant is without light long enough, the PFR will decrease past a tipping point. This decreased level of PFR signals the plants that Fall is approaching; and the plant begins flowering.
In short, the presence of PFR due to long hours of light and short hours of darkness keep the plants in the vegetative phase. If the plant experiences enough hours of darkness, most of the PFR turns to PR ; and the low level of PFR signals the plant hormones to begin flowering.
Practical Applications
Enough with all of this scientific mumbo jumbo. Let us look at how we can take advantage of photoperiodism.
How to Induce Flowering
Because of photoperiodism, you can easily induce flowering in cannabis plants simply by changing your grow room light cycles–reducing the light from 18 hours a day or more, to only 12 hours each day. Again, what is really important to the plants is changing from six hours of darkness or less to 12 hours of darkness. Within two weeks of switching the light cycles to 12 on and 12 off, you should see small buds starting to form.
I need to stress the point that your plants are very sensitive to any light during the dark period. If you have any light at all leaking into your grow room, during the 12 hours of dark– even momentarily–the PR can change back to PFR. Â This means that any light reaching your plants during the dark period may sabotage the flowering process.. For this reason, Â you should never–not even for a moment–enter your grow room when the lights are turned off in the 12/12 cycle.
Before you make the switch to a 12/12 light cycle, you need to make sure your grow room has no light leaks. Enter the grow room while the lights are out and close the door behind you. Wait about 15 minute minutes for your eyes to adjust fully, then look around and make sure no light is entering the room. No light under the door, through a curtain, or shining from a CO2 generator or dehumidifier. I have made this last mistake myself. If any of your equipment produces light from the display, cover it with duct tape, making sure no photocells have been accidentally covered. Â If you can see your hand in front of your face, you have a light leak that needs to be fixed.
While simply changing to a 12/12 light cycle will induce flowering, there is a trick to jump start the process. Between the switch from an 18/6 to a 12/12 light cycle, let your plants sit in total, uninterrupted darkness for 36 hours. This will cause the PFR to drop substantially, giving the plants a strong signal to flower. After the 36 hours of darkness, begin the 12/12 light cycle. In a side by side experiment, I saw significant results from this method. Be sure to flush out high nitrogen “grow†fertilizers from your growing medium and change to a high-phosphorus “bloom†formula. Also, adding high potassium supplements for the first two weeks can help increase rapid bud development
Light Deprivation For Outdoor
Through manipulation of photoperiodism, growers can induce early flowering in outdoor cannabis plants. It is much more difficult to make the great outdoors artificially dark than it is to turn off the lights–but not impossible. Many growers have perfected the art of light deprivation, and used it to harvest their outdoor crop in midsummer, or even multiple times each year. This can be achieved by building a garden that can be covered after the sun goes down, and then uncovered part way through the morning. If timed correctly, this can lengthen the natural night to a full 12 hours of darkness. The garden must be covered for several hours each day without exception, through the entire flowering period; but the effort can bring impressive early harvests.
Spring Clones
I can’t count how many times I have received urgent phone calls from alarmed acquaintances who planted clones outside too early. Despite what anyone says, clones can do amazing things if properly grown outside. Unlike seeds, however, you need to be aware of the hours of natural light when planting outside. Because clones are likely accustomed to 18 or more hours of light, they often begin to flower once placed outside in early spring. It will depend on your latitude and the strain; but at least in California, the nights are usually too long to plant clones outside before mid-May.
By using supplemental light to decrease the hours of darkness, you can plant your clones outside as early as you like. Simply clip a florescent light with an aluminum reflector onto a stake or cage around the plants. If the light shines on the plant for even a few hours after the sun goes down, it will usually be enough to prevent early flowering. If you are afraid of late frost, you can use an incandescent bulb instead, and also take advantage of the heat it generates.
Power Outages & Light Interruption
Even with light timers and a fully automated grow room, sometimes things go wrong. If the power goes out, or you need to change lights around, keep your light cycles in mind.
When your grow room is running on a 12/12 flowering cycle, a short power outage is not a major problem. A few extra hours of darkness will not really mess things up. Of course, the plants will not grow much without light; but they should be fine for at least two days. Any longer than two days, and they will start to suffer. This will not kill them, but may cause them to become stressed.
When running on a 18/6 vegetative light cycle, a power outage resulting in long hours of darkness can trigger the plants to flower. You need to find an alternative source of light for the grow room. An electric or gas camp lantern will be enough to prevent the PFR from dropping. If you need to change things around and interrupt your normal dark period, just leave the lights on until the following dark period. A few hours of extra light will not hurt anything. Remember, you do not need enough light to keep them growing–just enough to make it not dark.
- To maintain vegetative growth, use 18-24 hours of light; six hours of darkness or less.
- To promote flowering, alternate 12 hours of light with 12 hours of darkness.
- When switching light cycles from vegetative to flowering, first give plants 36 hours of darkness.
- To harvest outdoor plants early, cut the time light reaches the plants to 12 hours each day.
- To plant clones outside before mid-May, supplement with artificial light at night to prevent early flowering.
- During 12/12 flowering, additional dark hours are acceptable if necessary.
- During 18/6 vegetative growth, additional hours of light will not cause problems.
Successful marijuana growers know how to manipulate the environment of their garden. Once you become comfortable with light manipulation and photoperiods, the sky is the limit.
Light Cycles and Flowering Cannabis,
I’m a new grower, how do you know when it’s time to start the plant to flower ” When to switch frome 18 hr to 12 hr ? Another words how big does the plant have to be to start this stage? I am growing inside.
when your plant is about 20 inches is usually a good time to switch into flowering….it is then u change from 12/12 but a good tip is to leave your plants for 36 hours before u change your cycle…this will help in the budding stage.
I have already started my 12-12 cycle, going on day 5
then i read about the 24 or 36 hr lights out
can i still do it ? or is it to late ?
new grower and wanting to learn it the right way, the first time 🙂
plants are 32″ tall and hella healthy
7x5x8 room under a 600 watt air cooled light
would love some thoughts on this
You asked a Great question that Lots of Beginners and “young style” growers as I call them.Its Most Important that you know what Strain you are dealing with first.All different Strains Need more time to Ved And More Time to Flower.They Can Start to Bud at 6″ or 26″ it all depends on the genetic.If your plant looks yummy switch that thing to 12 and 12 then Enjoy!
@Elly110
Well that can be a tricky judgement call, there are many factors that need to be considered.
first, what kind of light are you using?
higher wattage lamps produce more light and can cover greater areas, also brighter light can penetrate deeper into canopies and is effective over greater distance.
Second, What strain are you growing?
Many strains like to double their vertical height after being flipped to 12/12. Kushes are famous for this, diesels too. You don’t want to run out of head room like Big Slugger did in his blue dream grow.
http://www.youtube.com/watch?v=g3t2Mn1KY7U&context=C3ae5ee4ADOEgsToPDskJFD9zq2cYZ_skJmJDb7mQY
Third, what is your intention?
When growers grow “sea of green” they veg their plants for a very short period, perhaps 2 weeks or less. On the inverse there are growers who achieve up to a pound/plant (yes indoor) by vegging much longer.
So you see it is hard to answer such a vague question. Please provide more information and we will be very happy to help. Or better yet start a growers thread on our forum and show us some pictures so we can better understand what we’re looking at, a picture is worth 1000+ words.
Great read simple and to the point. I enjoy the outside and prefer to let nature work its own magic without complicating things.
A rule of tumb for the beginer about plant hiegth
1. Always assume your plant will atleast double in hiegth. So if you want a two foot plant start your 12 hour period at 1 ft. Using is approach will allow you to plan your grow space.
A point regarding height gained during flowering. I think this only happens with plants triggered to flower young. I triggered some indoor White Gold at 2 weeks old & about 10″ tall in a hydro grow, and it hit 5′, & my lights, a month before it was ripe. Had to bend it over, and it got too dense and was lost to mold. But, I’ve planted outdoors as late as 1st of June & early as 1st of March. The most I’ve ever gotten in a height increase after the start of flowering on those has been 4 inches. And that includes varieties, Critical+, Critical Jack, Moby Dick #s 1 & 2, Skunk #1, Power Kush, White Russian, THC Bomb, & my own strain of Indica & my hybrids using Mexican land race genetics & crossing them with existing hybrids, like The Church. Has anyone experienced more than that with plants that old?
Here is a link to sunrise & sunset calendars. Select your country, then your zip code and then select the month. ENJOY!
http://www.sunrisesunset.com/
Recently I watched a friend do back to back cycles of the same blue dream strain. The first cycle he did a normal light cycle switch from 18 to 12 and the plants more then doubled in height. Then next cycle he gave them a full 36 hours of darkness between switching from 18 to 12 hours and the plants hardly put on any further height. There could be another variable that was overlooked, but so far it has not been identified. I’m not sure plant maturity has anything to do height growth after flowering but it could be possible. I think it is more likely that it has to do with strain and light intensity. If the lumens are high enough, the plants will stretch a lot less.
Absolutely love the page, dedicating my whole grow op on your advice provided above, its my first indoor grow and im really excited with the results so far, only 2 weeks in (from germination) and they looking pretty. I just have 1 question; How soon is too soon to expose the plant to the 12:12 cycle? Growing in a attic (Roof), going to get a fan up there ASAP and not much to work with, read a comment where the guy said that by exposing the the plant thats at about 1 ft in height being exposed to a 12:12 cycle will cause it to double in length. Sorry if this comment doesnt make sense, quite high at the moment. looking forward to your comment
I planted a see I found in one of my bags and it is about 3 in tall now with 3-4 internodes. When will I be able to see if it’s male or female? I know the female will generate pistils however I’m trying to figure out when this will be so I can identify.
Thanks
Al plants in nature will usually achieve their maximum height. All plants ( all life period) has a maximum growth. The Liger is one exception as it has no growth regulator and keeps on growing. Once they reach that growth they are done gaining height. Sativas can be up to 20 feet, Indicas are usually 6 feet or so. So you induce flowering at 12 inched lets say. Marijuana is pollinated by the wind in nature, so taller plants will catch more pollen than a shorter one. When you flower at 12 inches the plant knows it has to get taller ( has the genetic capabilities to be taller) so it uses its last bit of veg energy to gain height. Thus you see stretch when you flower. Most indica dominant strains will double in height. Sativas can be even greater. You really need to know what you are growing. I hope this helps.
My timer stopped working (left on) in the 10th weak of flowering 4 at least 2 days. I cut down and dried but tastes like crap if this happens again what can I do?
I seriously doubt that the taste had anything to do with your timers being left on. More likely it had to do with the strain, mold, improper cure, not flushing or something you foliar fed the plants with.
The idea of inducing flowering by 24-72 hours of darkness between veg and flower, and the myth of building up resin in 48-72 hours of darkness right before harvest, ARE NOT NATURAL. When you go from 24/0 or 18/6 to 12/12 that is all that is needed to induce. As for the 48-72 hours of darkness before harvest, which I don’t think is mentioned here but applies being it’s a similar subject and many believe in the myth, that does nothing more either. If you wish to mimic nature more indoors a simple method is to switch from 12/12 to 11/13 in late flower to mimic the shorter days of fall and winter. Another myth is in late flower you need more light then 12/12, this is untrue as in late flower the only thing happening is hormonal resin production, not actual bud growth, bud growth has stopped by the final 1 to 2 weeks, so you can go under the 12/12 norm with positive results, but only in the last week or two. It’s amazing the amount of myths and opinions of growing that exist.
When growing indoor the idea is not to mimic the natural world outdoors. The idea behind hydroponics and indoor gardening is to surpass the results of growing in a natural environment. If you want nature, grow outside. Inducing flowering with a solid period of darkness between 18:6 and 12:12 does work to produce a more complete drop in PFR and build up of PR which tells the plant to flower. Is this natural? NO. Does it work to induce flowing faster than a normal light cycle change? Yes. Is it necessary? Not at all.
As for the other myths you mentioned… I haven’t even heard of these ones, so I would tend to discount them not only as myths, but probably pretty recent ones. As for dropping to an 11:13 light cycle in the last few weeks… I wouldn’t suggest this to anyone. Ultraviolet light creates a chemical change in the plants trichomes that produces THCA and CBDA. You really want as much of this as you can get in the later weeks of flowering. You certainly won’t get more UV light by dropping an hour of lighting. After the plants have decided to flower, as long as the PFR stays below a certain level, the plants don’t really recognize a difference between 12:12 and 11:13 anyway.
The trick is to tweak natural enough so the plant responds positively. Remember the plant knows natural and too far from that is stress….36 hours of darkness is nowhere near close. Stick to changing 18/6 to 12/12 to 11/13, small changes the plants will understand and not stress. Remember the plant has a certain amount of programming from nature over past million plus years, don’t screw with it too much. There is much to be said on this topic, I will try to answer anyone’s questions
I love how people say this is a myth and that is a myth because it’s just not natural but yet they say they veg in 24/0 light cycle. I wonder if you even read what you have typed.
Good one. You just gotta laugh. While I’m new to this site, I love it and I am continue to learn. I agree that if you know what the plant can do and you know how to make it do it indoors, then do it. Trial and error is expensive for certain. Prefer 18/6 veg and 12/12 flower myself. Plain and simply. Although I have had power outages force me into 36+ hours of darkness out here in the country. All I noticed was a stressed out me. In nature, the sun doesn’t eclipse for 36 hours. I’d say stick as close to “natural” as you can, but take advantage of these folks personal experiences. Good advice is valuable and free.
Drango, you are bang-on here! So many empty comments; peep should understand, you only learn by asking, not telling!
Let the experienced sources inform, try a new thing with ONE plant & pass it on!
Peace, bro!
ty for ur info on the 72 right b4 harvest im having this exact discussion with a friend now , thanks for clearing it up
Thank you for all the information, I was stuck with the myths and was messing up my first grow.
You guys are very clear thanks again.
Thank you. We do out best to help people like you along. For more assistance feel free to post any questions you might have in our forum.
after googling im starting to grow but im not going extra hard im just doin it for fun i always been able to grow marijuana but i never get it to bud. im jus starting now and im going to try the light trick to see if i can make buds i dont care how much i jus wanna accomplish flowering. ps if yall have any good strands yall can mail me ill appreciate it. or any tips
i got like 4 plants goin now and one of them has the strongest smell what that mean?
If you are growing cannabis inside, the switch from 18 hours of light and 6 of darkness to 12 hours of light and 12 of darkness then you should start seeing the early signs of flowering in a week or two. Whether the buds fill in nicely will depend mostly on providing them with sufficient light, feeding them, and keeping them alive. As for the strains. While you are experimenting look for the easier to grow strains that finish in 60 days of flowering or less so you have less time to screw it up. The longer flowering strains like Sour Diesel tend to be better in the hands of more advanced growers. As for mailing strains… I would advice purchasing some clones from a cannabis dispensary in your area, or buying seeds online.
HOW QUICK CAN I START FLOWERING AND DO YOU KNOW WHY ONE OF MALE PLANTS HAS A STRONGER SMELL THAN THE OTHERS?
y do you have a male in your garden at all unless you are growing seed instead of weed?
Tony, many growers start their plants from seed. Seeds very often produce male plants. If the person has never been able to get plants to flower as was sated above, there is a good chance the plants would not have shown sex either. While it’s quite likely that they do produce different smells, I doubt the human nose can detect such a subtle difference. I have a friend who thinks he can tell the difference between male and female plants based on the smell alone. I going to call bullshit until proven wrong.
SKUNK
**I MENT DO YOU KNOW WHY ONE OF MY PLANTS SMELL STRONGER THAN THE OTHERS?
No idea why one smells different. Could be a different strain, could be a different phenotype of the same strain. Could be the one that smells is a different sex from the others, or that it has matured faster… There is even a good chance that it means absolutely nothing at all.
WHAT IF I 12/12 FROM BEGINNING TO END?
AND THE ONE WITH THE STRONG SMELL HAV UGLY FAN LEAVES SO FAR
THEY ARE FAT AND NOT 7 LEAVES SOME HAVE 4 OR 5 LEAVES AND ITS ON THE 5TH SET OF STEMS NOW
@ New Major Grower
It’s important to understand why growers “vegetate” their plants. This is simply to allow the plant to put on some size prior to forcing flowering by reducing light hours. If you where to grow clones or seed without a vegetating period they will begin to flower almost immediately. Because days shorten as winter approaches, your plants will be confused into thinking they need to reproduce in a hurry. The results would be very small plants that produce very little bud.
Different strains behave differently, some plants will double in height during flowering, others will only put on a few additional inches, it really depends on genetics.
I was in the flowering stage and my timer messed up, Can I put back into a 36 hour state again?
Messed up how? Your best bet would be to just go back to the 12/12 light cycles but I suppose if you lights got left on for a long period to time there might be some argument for giving it a 36 hours of dark first. While I don’t honestly know, I suspect a long period of light followed by a really long period of dark may do more harm to the plants than simply dropping back to your 12/12. Either way, watch for herms.
WHAT THE BEST WAY TO MAKE MY BUDS SMELL AND TASTE GOOD?
CAN I MALE PLANT FERTILIZE A FEMALE BEFORE IT SHOWS ITS SEX?
While we love comments about our articles. Some of these questions have very involved answers and are better asked in the forum.
DO YOU KNO ANY UP TO DATE FORUMS?
Up to date forums? I’m not sure what you mean by up to date, but you are welcome to use the forum on this page. It’s a bit new so there aren’t a ton of people on it but most of the ones who are know what they are talking about. http://www.marijuanagrowershq.com/forum/
I have a question regarding preflowers, any helpful information would be appreciated. on June 5th I placed two clones outside in 5 gal containers( one harlquin and one super sour og). They are both growing rapidly, however the super sour appears to be flowering. Should I be concerned, is it possible this strain preflowers more than other indicas?
It is definitely true that some strain will start developing flowers long before other. It does seem a bit early for flowering but some plants will show flowering signs but keep vegging strong for months before really flowering. If you want to drive it back into veg you could try breaking up the darkness at night with some supplemental light.
what if you went from a 18/6 to a 12/12 without doing the 36 hours of darkness to jump start flowering.. is it okay and still helpful to leave lights off for 36hours? and its within the first couple days of switching light cycle…
If you have already done a normal switch to 12/12 then I would just leave the plants alone and let them flower. 36 hours of darkness can be helpful but is not necessary. At this point I think confusing them with light could potentially do more harm then good.
i won,t have any electric 4 two weeks and i have my plants one week into flower . what can i do
That’s a really tough one. Short of buying a gas generator and running your lights off of it, I’m not sure there is much you can do. If it was just a day or two a battery powered or propane camp lantern would be enough to keep the light cycles correct but I think two weeks with no real light would lead to some pretty messed up plants. If possible, I think your best bet would be to move them outside during the day for 12 hours and back into the dark room at night. Good luck with this one. Let us know if you come up with any creative solutions.
Sunlight for two weeks…the sun-power is uhhhh…free!!!!!!!!!
The questions was posted in June when the days were at their longest. The plants had already be switched to a 12/12 light cycle so they would not have done well if placed outside. While the sunlight is free to many hours of it will either send the plants back into veg, make them larfy, or worse make them herm. The could of course be covered to shorten the hours of sunlight, or brought in and out of the grow room to impose 12 hours of darkness… Lots of work
hey! first of all im not american, so im sorry for any language mistakes in advance! now, to the point! my plant is in the flowering stage for about 3 weeks now. i switched to 12-12 and within 3 days it was clear i was lucky enough to have a female plant. buds started to develop, plenty of white hair etc. then i had to leave for 1 week, and my friend who was supposed to take care of it, accidentaly switched off the timer. as a result, my plants suffered bout 5 days (!!!) of constant light and heat (i live in a pretty hot country during summer) during their very first days of flowering. since then i dont see any significant development in the buds. some brown hair showed up, but still, buds arent growing for the last 10 days or so. Also, i wasnt aware they need absolute dark so i didnt check it out the way u suggest. i assumed that since lights are off, they have what they need! anything to suggest? any way to save it?! thank you..
The constant light for 5 days would have sent the signal to the plants that they should go back to vegging instead of flowering. This back and forth in addition to the extra heat has probably shocked the plants a bit. You have two options, you can switch back to 12/12 and at some point they should start to flower again, or give them the 36 hours of darkness followed by 12/12 and hope for the best. At this point the 36 hours may just confuse and stress the plants even more so I’m not sure its a great idea. Sometimes these things happen. Wish I could be more help. We’ll cross our fingers for you.
i did set them right back to 12-12 as soon as i got back to my place! that was bout 10 days ago but i cant notice any real progress since then! i think i ll keep it for another 10 days and if no progress made, i ll let it…rest in peace! Man growing that plant is a real pain in the ass regarding the level of difficulty and sensitivity! thanks for the info!
Please Help! I’m at 9wks of flowering Mr. Nice and the lighting schedule (timer issues) must have varied enough to cause my plants to start to return to veg. I should be harvesting in a week or two…. Should I harvest early? Cut light back? Shut lights out for a bit? Help please!! They look awesome but new little green nodules look kinda alien like. HaHa
First I think we need to know more about these timer issues. Even plants given 13 hours of light will generally still flower. Of course if you have been sneaking in the grow room every night with a flashlight then you have been interrupting the darkness and this could certainly screw them up. As for them returning to veg… Im not sure what you are seeing, but a picture in the forum would probably help more then 1000 words. While I have never grown Mr. Nice before, my understanding is that it is a 8 week (60 day) strain. Many plants that have fully matured buds but are allowed to continue flowering will begin to open up again, thought usually not after only an extra week. Tight buds can suddenly begin to open up and begin new growth. Take a magnifying glass and check out the trichomes, if they are becoming milky or amber instead of clear, it’s time to harvest. Changing the light cycle at this point isn’t going to do a bit of good. If you decide to keep flowering, keep them at a 12/12 but your about done anyway. Very few strains take longer then 10 weeks indoors. Good luck.
hey boss this has nothing yo do with any of these topics. long story short, somehow some way i left my 1000w hps light on , turned off the fans snd shut the door as they were going into their night cycle and i went to my 10 hour a day job. i got home and yeah….they were dry as all get up but still had some moisture to them. can they be saved?
Further research and I’m finding that Mr Nice is a 9-10 week strain. Still, I think you are probably close to done and can safely harvest without sacrificing much potency.
I accidently set my veg timer to 12-12 for two days..then when I reliezed what I did I switched it back to 18-6. What do you think I should expect happen?
I think you will probably start seeing some flowering signals, but as long as you keep them on 18/6 and keep them on high nitrogen nutrients they should snap out of it. This is a common way for outdoor seed growers to sex there plants early long before the normal switch from veg to flower in early august.
I started several tga subcool strains from side indoors andf vegged for about 3months. Then i put them in greenhouse in end of april and they got huge and began flowering in mid-may. Now at end of june, some not all are reverting back to veg. When they do eventually finish up will the reverted ones have an inferior yield because of its confusion?
Karen,
You’ve made the same mistake that many growers make. It’s fine to start early inside and move out into a greenhouse or into the ground but if done before about mid May, you’ll need to add a few hours of supplemental light to make the days long enough to keep them from flowering. This is not a problem with seeds, but clones will start flowering almost every time. The supplemental light will prevent this until the days are long enough to keep them in veg. As for dealing with the problem… you have two options. You could keep them flowering and do an early harvest with light deprivation, or you can wait and see what happens. Really it will depend on how far into flowering they were before they went back to vegging. I expect it will diminish your fall harvest considerably if they were far along… but you never know. It’s a hard lesson to learn, but your not the first, and you won’t make that mistake again.
I do this nearly every year, it gets them sexed, then they grow more and then produce a bunch of well developed buds. Just make sure you keep them well nourished for such a long grow.
Thanks Rambo..even if it might have been 3 days? Thanks again..There deffinantly in shock but have my fingers crossed..PEACE
I have been going a couple years now but have had some bad luck lately. let me tell u i have a 8×8 tent, filled it with babies i mixed ss early budd with jackhearer. now i pushed them to sex them then vegged, then flower. they all looked diff but the more shorter ones were beautiful and fat. then all of a sudden BAM, no more growth, then i saw seeds. harvested early. i at no time seen it coming. it was potent but tasted like garbage. now i am doing in and out and i have 4 outta many in full cola bloom, why? i was terrified to turn them herrmy soo i bring them in early but not the same time due to work so sometimes they r in 15hrs of night. they look amazing but am i at risk. sorry so long. Dez
Dez, I wish I could help, but I don’t have a really clear picture of what you are up to. Let me see if I have this right. You crossed ss early bud and jack that you started from seed and decided to sex them before allowing them to veg. Then you planned to go back to veg after sexing but they wouldn’t grow any larger and instead they started to flower out, but then you found seeds so you harvested early. Either you missed a few mails or you had some plants herm on you. This could be from a lot of things you are doing wrong, or possibly the genetics you created from the cross or the parent genetics have a predisposition to herm. As for why they stopped growing… it seems pretty evident that they didn’t like being sexed, so I would suggest not pre sexing them if you are going to grow from seed. Let them sex themselves or grow from clone.
So now you are doing indoor and outdoor with the same strain and 4 of them are in full cola bloom. This makes me think you may have unlocked some kind of recessive determinant gene from some long lost ruderalis heritage and they are wanting to flower regardless of hours of light. I’m not really sure what this has to do with your fear of them herming though. I apologize for not having a clear cut answer, but honestly I’m not even sure I know what your questions is. The more articulate you are with your questions the easy they are to answer. In the future, the forum is probably a better place for longer questions like this.
My question is can the four i bring in to create longer night cycle screw up my plants because it is diff everyday but never short enough to revert back to veg?i mean outta 50 outdoor 4 are in full bloom and they get direct sun all day.so can a plant have too much darkness?
If they are in full bloom, I’m not sure how much good it will do to extend the hours of daylight, but it’s worth a try. It’s possible you can talk them into vegging again but upping the light to 18hours a day. Remember, you don’t necessarily need grow lights for this, any light with some red in the spectrum will do. You could even leave them outdoors and give them a shop light or something. If the plants already have some size to them, you might consider keeping those four in flowering with a light deprivation system. To many hours of darkness won’t really hurt a plant, but it will make them flower, and even they don’t receive enough light they won’t grow or flower very well. Hope this helps
Thanks for the info,yes my plan was to keep these going in bloom but i was hesitant because my darkness fluctuates
I thought males made themselves known early, meaning, even in veg state they start to change before the ladies. I grow outdoors and lost track of month because of the season lol and my Sativas are almost 3 Ft tall flowering now on week 3 but it took 3 months for 3 of my 5 plants to show their balls
Any advise would be great
Best way to cover the smell indoors?
As this is an article about light cycles, you question would be more appropriately asked in our forum.
http://www.marijuanagrowershq.com/forum/
I am 6 weeks into my light dep. Is it OK to leave the tarps off all day/night now?
I guess it really depends on the number of hours of daylight/darkness at your latitude. If your nights are long enough then it should be fine. On the other hand, if you are only a few weeks away, why risk it?
I am in northern california and can not be home to cover for 5 nights. Wondering if I should continue to cover after those 5 nights? Also is the extra sunlight beneficial in any way?
Hi Bonny,
Missing 5 days of covering your dep house is unfortunate but not disastrous. The worse case scenario is that the plants will begin to vegetate again during this time, and then revert back into flower after you return to your schedule. Please excuse the expression but I often refer to this condition as “photofucked”. This refers to buds that have begun to branch out, the result is hundreds of tiny crystal covered branches instead of tight flowers.
I’m tempted to recommend that you leave them covered while you are out and just stick a 4 foot florescent light in the enclosure on a timer, but the forecast calls for higher temperatures in the following days and that could cook them.
If stepping out for a few days is unavoidable and there is no one you can ask to cover the plants, they you have few options, I think they should be alright. Best of luck on your dep project and I hope you have a wonderful time while you are out.
I’m going to agree with Gore. Currently the sun is up for about 14.5 hours between sunrise and sunset. This is not an ideal day to night ratio for flowering. I suspect they plant will wonder what the hell is going on, but probably not respond to poorly over only 5 days. I think if you are already pretty deep into flowering then you should be fine.
I’m a 3rd-year med grower in Montana with 3 plants about 5′ tall in a greenhouse. Autumn comes on cold and fast and I’ve found my plants struggle to finish, so I’d like to get them flowering just a week or 2 early via light dep, but then allow the shorter natural days to take over. Is this possible?
I have seeds grown by a former caregiver (MT’s law has changed drastically for the worse and my options were limited) but they’re all sisters of an 8-ish week strain – his “Honeymoon A” x with a Sour Bubble dad.
So the question: How do I know when they’ll begin flowering but NOT revert to veg after I stop with the light dep?
Thank you in advance for any help!
In California seed start plants will usually start flowing on their own around August first. This is of course dependent on the strain but its a pretty safe general rule. I think if you started with a dep right about now, you can probably go back to natural light by about mid August without taking any real risk at reverting back to Veg. I would say this is playing it safe, and you might be able to get away with a lot less dep time. Remember, cool nights are usually not the problems for finishing up. It’s usually more of not enough days of intense light in the summer. This is particularly true of more equatorial sativa strains. You might have more luck with a higher altitude indica strain.
Can i start the flowering process after only 2 days of vegetation?
You certainly can, but with only two days of veg I would probably not expect very large plants. Even in see of green (SOG) setups, I usually see people doing at least a week of veg to help get the roots established.
I started plants the end of April. I had one plant get to 12″ and then bud. It has only grown about 3 since budding. All the other plants are in normal cycle. I took the height challenged one inside at night allowing only a 12/12 cycle. I’m not optimistic about it growing any larger but…I’m not sure what may happen, bringing it to a 12/12, but it does look nice and swewt smell. BTW, I’m unsure of the strain. I’m thinking it could be a low height strain. Any ideas?
Not sure what happened to that little one. It could be some auto flowering genetics got worked in at some point.
I got a plant thats about a foot tall and Iv had it outdoors for about 2-3weeks. I’m about to bring it inside and put it under 12/12 and I was wandering how long does it take for the buds to actually start forming. And how long will it take for the buds to actual get decent size where I can be done with the plant and harvest it.
Any ideas or suggestions??
Jacob,
There are a few factors that you did not mention on your question, most importantly perhaps, is what strain it is. Indica land-races will form flowers and ripen faster than Sativa land-races. In general you should begin seeing flower formation in 2-3 weeks and the plant should be ready for harvest 8-10 weeks after 12/12. Please remember that these numbers are generalized and you should expect your results to vary.
ive been growing my baby for three months outside. Its 3ft tall, beautifil, and the smell is amazing. unfortunatlly i have no buds. how can i start 12/12 if my plant has been outside the hole time? Please help!!!!
There is no reason for concern. Many outdoor plants don’t begin to flower until early August or sometimes even later. If you want to induce flowering early, you can use light deprivation to reduce the hours of sunlight and shorten the day. I’m not sure I would recommend it at this point though. Just let them do their thing and be patient.
I started may plant in May outdoors. Will it produce buds naturally without light deprivation?
Don’t over think it. It’s a plant. They flower on their own in the wild just fine. As long as the plant is getting plenty of light, water, fresh air, and some kind of fertilizer you should be just fine.
but dnt know the strain.
Its growing so tall it’s getting hard to hide. I have mirrors surronding it for extra light. Hopefully if i let it be, and do it’s thing outside it will produce.
I don’t seem to be able to give you the answer you are looking for. I suggest you take your delima to our forum so others can try to help you.
won’t reflecting the light with a mirror produce heat?
Yes. Mirrors can create hotspots which can damage plants. Flat white materials usually reflects the most light and work much better.
This may be off topic but I got a clone that’s not very tall but I just now transplanted it into a bigger pot and brought it outdoors and I looked at it today and the leaves are all droopy down. Is it about to die or something? I know for a fact I didnt over water or under water it, so i dont know caused it but any suggestions on how to make the leaves stand straight back up…
Yes this is off topic and better suited for our Forum. Take it out of the sun and make sure it has plenty of water. The plant is most likely in shock from being transplanted to roughly and needs a few days to adjust.
Just a curious question when u switch into flowering is there anyway u can trick ur plants? For instance let the lights go 24hrs one day on an the next day 24 hrs off.. or every 6 hrs switch the lights on and off. An if so what are the results????
Sure you can trick the hell out of them with whatever light cycle you want and results will vary based on hours of darkness. Read the article again and I think it answers all of these questions. 24 on and 24 off will produce flowering, and 6 on and 6 off will keep them in veg. The hours of darkness is what is important, not the hours of light.
So ur saying that I can do 24on/24off for flowering? I’m a beginner an just tryin to get certain tips on things! As far as my veg stage I’m gonna keep it 18/6. I wanna try something different as far as the flowering stage to see which way will produce more progress then just 12/12. So as for the 6 on 6 off id probably be better off doing a 6 on 12 off an 6 on again or 36 off 12 on? Like I said I’m a beginner an trying to learn different things that’s all…
you could do 24/24 or 6/6 but that is a lot different that me suggesting that you should. If you are just learning the ropes don’t try to reinvent the wheel. You have a pretty steep learning curve as it is. 18 on 6 off for veg, 12 on 12 off for flowering. Don’t make it more complicated then it needs to be.
when starting to flower, what is the best hour to start the new 12/12 cycle? If my veg cycle was 6am-1am would it be best to start the new flower cycle at 6am, ending at 6pm or to start it at 10am, ending at 10pm?
All other things being equal your plants won’t really care. The biggest factor here should be what hours are convenient for you to work in the garden. If you go to work at 8 am and don’t get home until 6pm then you’ll probably want those extra evening hour with the lights on to get you chores done.
In addition to what Rambo mentioned, consider temperature. Some growers prefer to run their lamps in the evening when it’s cooler.
my buds are just about done was just wondering whens the best time 2 harvest them in their light cycle or dark cycle and is not watering them for a few days before harvest good idea?
Water the plants up until the day of harvest. However you can stop fertilizing up to a week before harvest to allow the plants to flush out some stored nutrients. Terpenes build up during the dark period and begin evaporating under the strong light, harvesting just as the light come on and then drying in a dark or dimly lit area will help preserve these terpenes.
Just had a quick question.. I leave my (indoor) flowering tent open during the lights on period, for ventilation, and zip it back up before lights out (it is in the the same room as vegging plants). The last two nights I have been roughly 5-10 minutes late zipping it back up, and I am concerned about hermies popping up as a result. Should this be a concern, or am I over-reacting? I have plants in early, mid, and mid-late flower. Any feedback would be helpful.
OMMP
The practice of leaving manually opening doors to 12 hour rooms is a common one. Many growers resort to this routine to help mitigate high temperatures. If you are a few minutes late, it should not be a big deal, but it’s not ideal either. Make every attempt not to be late and consider upgrading your cooling system so that you no longer need to open the tent door. Another option may be to run your 12 hour room at night when it is cooler.
Question my unkle left these plants in the back yard… I just moved into his old house. the plants are about like 5 or 6 ‘ tall. He said i can have them. i want some bud but I am so clueless how to do it! Im willing to learn if poss. I just want me some bud 🙂
We would be more then happy to help you with your questions. Join the forum and ask away.
hello mate i just want to know how long i can keep the lights 18/6 till i go to 12 / 12 and how long i can keep 12/12 do i need to untill the last day, many thanks mate
Keep the light on 18/6 until you want them to begin flowering. Keep the light on 12/12 until you harvest.