New Grower The life cycle of auto flowering cannabis.

Another common question I see is when to switch autos from veg to bloom. Many people are under the impression that as soon as they see the first flowers it's time to switch. Perhaps a little explanation of the life cycle of autos will help to clarify this.

Weeks 1 - 3. Once you've started your seeds and they break the surface of the soil, they are in their seedling stage. The first set of leaves to appear will usually single fingered, followed by a second set that may still be single fingered or perhaps 3 fingered. Once that second set appears growth will start to accelerate as the new leaves provide more photosynthesis. This process will continue, more new leaves, faster growth. Depending on the type of soil in use, mild vegetative nutes can be introduced at week 2. By week 3 most plants will start to show their sex. Males will start to produce pollen sacks and females will display pistols.

Weeks 4 - 6. The plants are now entering a pre flowering stage. During this time the plants should exhibit explosive growth, often as much as a new set of nodes and 1" vertical growth a day. This is the time when they will gain most of their vertical height. Many people make the mistake of switching from vegetative to flowering nutrients at this point, assuming that since they see flowers it must be the proper time. This is incorrect. If the switch to flowering nutes is made at this time the vertical growth will stop and the plant will put it's energy into producing buds. If you need to keep your plants small, or want them to finish earlier, they by all means switch nutes at this point. But if you want to get the most out of your plants continue feeding vegetative nutes until you see the vertical growth slow and stop. Depending on the strain that will usually be sometime during week 5 or 6.

Weeks 7 - 9. By now vertical growth has stopped and the switch to flowering nutrients has been made. The buds will start to fill out and put on weight, becoming hard and tight. Pistols will start to change from white to brown, orange, red, etc. By now the plants will also have developed a strong smell. Toward the end of this phase the large primary and smaller secondary fan leaves will begin to turn yellow. This is an indication that the plant is moving toward the end of it's life.

Weeks 10 - 11. At this time flowering nutes should be discontinued and only plain pHed water fed to flush the remaining nutrients from the soil and improve the taste. Yellowing of the fan leaves will continue as the plant draws the stored energy from them. Eventually they will die and fall off. By the time that the smaller leaves that come from out of the buds will also start to turn yellow. Then it's time to harvest.

I know that many of you are thinking that the seed bank said the plants will finish in 8-9 weeks, so why are you saying they take 10-11? The claims made by the seed banks are somewhat deceptive. If you switch to flowering nutes at week 3 or 4 the plants can finish in the times the seed banks say but they will remain small and not reach their full potential yield. Years of growing by myself and others has shown that autos do best if you follow this time line.

Of course, there will always be variations depending on the strain, the environment, nutrients, etc. This information is meant to only serve as a general guideline.

For more detailed information on when to harvest your plants, please see: https://www.autoflower.org/f44/when-harvest-autos-your-leaves-will-tell-you-4889.html.

NOTE: This is an informational thread. Do not post specific questions about your grow here. Please start a new thread in the appropriate forum.
 
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No, I've never said using flowering nutes stops vertical growth. But feeding flowering nutes during veg will slow vertical growth and encourage them to flower sooner than may be desired for optimum yields. I keep a yard stick in my grow box and measure them daily during veg. When I see it start to slow, then stop, I know it's time to switch nutes and lower my lights.

Does vertical growth stop when no new leaves are coming up and there is just a bud sight on top? I kno u said switching to flowering nutes stops vertical growth but since no new leaves will come on top does that mean vertical growth is over? I haven't even added veg nutes yet..

any idea?
 
thanks for the very informative post muddy.

bookmarked / added to favorites / etc. lol
 
Muddy, I've been talking about this (and the harvest guide) with someone and he asked me a couple of questions I couldn't answer.

His point was that he starts autos in a smaller pot then pots up around week 3 (when the first pistils appear). That new pot has new compost in with about 3 weeks worth of food in it. That brings the plant to the end of week 6 and bloom nutes start at week 7 (assuming vertical growth has stopped).
That being the case, why do you suggest feeding with veg nutes as early as week 2?

He also questioned why flushing applies to soil (and asked if it was written for coco growers)... which is way over my head. Any input on that?

Cheers. :)
 
In his situation he may not need to feed veg nutes, and if he did, would only need mild doses. I grow in Pro Mix, which only contains starter nutes. They are usually exhausted within about 2 weeks and if I don't feed, will start to see signs of N deficiency.

The 2 week flush at the end of the grow removes any chemical residue from the plants and makes for a better taste and cleaner burning. Not as important if growing organic but pretty much a must if using chemical nutrients.

Muddy, I've been talking about this (and the harvest guide) with someone and he asked me a couple of questions I couldn't answer.

His point was that he starts autos in a smaller pot then pots up around week 3 (when the first pistils appear). That new pot has new compost in with about 3 weeks worth of food in it. That brings the plant to the end of week 6 and bloom nutes start at week 7 (assuming vertical growth has stopped).
That being the case, why do you suggest feeding with veg nutes as early as week 2?

He also questioned why flushing applies to soil (and asked if it was written for coco growers)... which is way over my head. Any input on that?

Cheers. :)
 
How do autos fare with the cold? The rudiralis genes shoud have a hardyness for cold built in woud'nt they?I don't mean the roots but the top part.
 
Thanks very much for that, Muddy.
I'll pop back in if there's any more discussion that goes over my head. :D
 
The 2 week flush at the end of the grow removes any chemical residue from the plants and makes for a better taste and cleaner burning. Not as important if growing organic but pretty much a must if using chemical nutrients.

Yo Muddy, when you say 2 week flush, do you mean you flush your plants over the 2 week period (for a 10l pot give the plant 20 liter spread out over 2 weeks), or do you mean you flush it once (like feeding the plant 20 liter water in one time for a 10l pot), 2 weeks before harvest and then only feed plain water when the soil gets dry? (in the case you use soil)
 
How do autos fare with the cold? The rudiralis genes shoud have a hardyness for cold built in woud'nt they?I don't mean the roots but the top part.
Here in the north I hadn't seen yet any GOOD RESISTANT autoflowering outdoor plant which was breeded indoors. They all just mold away, leave you half of its micro-harvest yield. I mean such strains as: LR; autoak; bluestreak; diselryder; onyx; etc. all LR based "strains".

by the way feed NPK rate to 2-12-20 in flowering. more additional "K" helps plants to resist cold when autumn comes.
If you will you spray potassium bicarbonate (E501) solution you will prevent mold and add "K" too.
 
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Question on auto harvesting outdoors. Do you still try to wait for all the fan leaves to yellow before harvesting?
I've got a test NLxBB auto going outdoors in the NE (planted ~ 10/9) & the leaves are turning purple, not sure if that's an indicator or just the strain. Plant got put in the ground late & was somewhat mistreated through ignorance (mine) when it was small. It's only 9/10" but has plenty of leaves & small buds.
Thanks.
 
:confused:
Question on auto harvesting outdoors. Do you still try to wait for all the fan leaves to yellow before harvesting?
I've got a test NLxBB auto going outdoors in the NE (planted ~ 10/9) & the leaves are turning purple, not sure if that's an indicator or just the strain. Plant got put in the ground late & was somewhat mistreated through ignorance (mine) when it was small. It's only 9/10" but has plenty of leaves & small buds.
Thanks.

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