What causes autoflowers to flower?

[The Iconoclast]

I just realised, one was grown in winter with moderate indoor temps and chilly nights, the other was in the summer with warm nights. Otherwise the only difference in treatment was instead of letting a lot of undergrowth develop and then cutting it all off when she was already flowering and doing this a couple of times, instead this time, I only did a very small early prune and then I anticipated all the undergrowth and pinched out the shoots before they could develop, so there was no work to be done. The heat, or the early pruning or a combination of those two things would be responsible. Unless it's a phenotype but I don't think so. The Winter one was 13 zips of dense bud maybe slightly more open, the Summer one will be very much less, maybe 4 or 5 if I'm lucky, but nice solid buds, that's the current one that is not at 11 weeks yet.

 

[brock1]

Ho can I answer this 1 please? Pick me pick me

 

[brock1]

In Ruderalis the auto trait studied by ncbi.nlm.nih.gov photo neutral was found to be caused by. GAGANTEA (GI) binding CLYING DOF FACTOR1 causing a over expression of GI in the KKF1 mutation. This causes early flowering (photo neutral) through excessive producing of CDF protein. Hope that help the needs.

 

[Rasterman]

This makes sense and I'm guessing yield is higher for the bigger pots also.


My only idea is that constant transplanting is effectively the same as starting off with a bigger pot, but it adds more time in the veg phase. Longer grow could allow for a bigger plant. I think for this idea to have any chance of working you must have perfect transplants with minimal stunting.

Most of the autos I've grown were started in small pots and up-potted as they grew. But my yields are typically quite low. The times I've up-potted to a large pot in the first three weeks, however, yield at least 3x more.

 

[GreenBean]

Forgot about this thread as well.

Only evidence I have for a much larger pot size, and I’ve been playing with it, is from my last completed grow. Different strains.

10 gallon pot vegged about 55 days. Finished in 110 days, 20.5 oz yield.

2 plants in 5 gallon pots. Both vegged around 35 days. Both finished around day 91. 13.4 oz and 9.9 oz.

Never grown in anything under 5. Only 5, 7, 10. My average 5 gallon grows veg for around 35 days, 7 gallon average 40-ish and the 10 gallon, 55.

Last run:

 

[pop22]

I think your partially right. It's a combination of genetics and environment. I don't think it has anything to do with the tap root however, I believe it is the total volume of soil that has some affect. I find that in 20+ gallon containers flower tends to initiate around 34-45 days. Same in raised beds, I see flowering begin around day 35. So my theory is that once the root mass to soil volume is reaches a certain ratio, ( in containers ) flower is triggered.
I would love to see some science applied to autoflowers to get to the truth of this one way or another!

I'm going to chime in and say that I firmly believe that the bottoming out theory of the taproot triggers flower - to a great extent. I have taken seeds from the same pack and grown in a 5 gallon vs a 7 vs a 10 gallon and the 5 gallon pot flowers and finishes much sooner. Just one example.

It will have to do with genetics too. You're not going to take an OG Lowryder and get a monster.

I don't understand the constant transplanting part though. I mean, you can just pop a seed into a 5,7, 10 gallon and save a lot of hassle.

 

[GreenBean]

I think your partially right. It's a combination of genetics and environment. I don't think it has anything to do with the tap root however, I believe it is the total volume of soil that has some affect. I find that in 20+ gallon containers flower tends to initiate around 34-45 days. Same in raised beds, I see flowering begin around day 35. So my theory is that once the root mass to soil volume is reaches a certain ratio, ( in containers ) flower is triggered.
I would love to see some science applied to autoflowers to get to the truth of this one way or another!

You may be right about the tap root theory, and in hindsight I don't disagree with you. It may "bottom out" rather quickly.

As someone stated a page or so back, it could be due more to the roots as a whole thinking that they have run out of resources and then that signals flower mode. What leads them to determine that I do not know.

I DO see extended veg times in different sized pots though. But I do run coco indoors. I have not grown autos in soil, outdoors, in a good while. So maybe medium helps to determine as well. If I am dumping nutes constantly into the coco, they may keep going until they finally hit a point where they "have to" go into flower mode. I grow my autos as a challenge to outperform the typical photo. I have little desire in having them "finish fast". One thing I notice about my grows, is that my plants seem to grow outwards until they almost fill the entire pot in girth, as in no more room to grow outwards, and then they start growing upwards.

 

[Talonxracer]

I have a rather complex light system starting with a xs1000 full spectrum quantum main board with additional led's from 385nm thru 505nm in 10nm steps on 2 heatsinks along the long edges of the main board and along the short ends I have additional 680nm, 720nm and 735nm diodes. The main board and additional led's are controlled by 2 Coralux pwm dimmers with sunrise/set slopes. I was growing a single Early Miss auto in a 2.5' x 2.5' tent in a airpot that sits on a turntable timed to make a 1/8 turn every 1/8 hour.

Now getting that out of the way,, I screwed up on day19 several grows ago and instead of increasing both time and intensity for the blue/violet channels for vegg, I mixed up the controllers and decreased the blue/violet and increased the red channels. The plant then over night stretched like mad and nothing I did slowed the stretch and by the end of the third week it had stretched the main stalk nearly 16" with flowers the size I normally don't see until the 6th week. Eventually I had to add some led strips into the corners of the grow tent so the lower part of the plant received light due to the height of the main cola.

At day 74(Early Miss usually harvests between day 74-77) the only thing left on the plant were buds, no leaves. The plant I ended up with was rather phallic in appearance and the diameter of my forearm rather than the normal indica bush, but gave me nearly twice the normal harvest with enormous buds with that extra 3 weeks of bud growth.

I have used this procedure twice on purpose now with similar to better results. So yes you can cause some auto flowers(I have only tried three different autos, early miss, gg#4 and blackberry) to flower early on command by changing the ratio of red to blue light by reducing both intensity and duration of the blue/violet output of your grow setup and/or increase the intensity of the red spectrum and use a 730-740nm led puck(12w) for a 15 minute sleep/wake signal, all the while maintaining a 18-6 day/night schedule.

 

[Talonxracer]

Here are a few pics showing what happened to the plant,
I had 2 plants going both early miss planted on the same day but different tents and lighting setups, the first grow tent had just a viparspectra xs1500 in a 2x2 tent, the second had the xs1000 with additional leds. Both pics taken on day 19!

And here is the one I forced to flower early

And here they are at day 44

And the phallic early miss

 

[pop22]

The breeding of autoflowers is a fairly new thing, so there is a lack of science related to them. Everything is still supposition at this point. We can make some very limited theories about them based of papers such as the one SoH posted. The mechanism on Ruderalis may or may not function in the same manner, I suspect it is similar, but we won't know until someone does a real science study on autoflowering cannabis. Remember, it was not that long ago, autoflower were laughed at and considered a waste of time!