Different ways to break apical dominance?

[Phillybonker]

I know there is topping, LST, FIM, and super cropping to break apical dominance but is there any other method, or anything I can add to the soil to break dominance and get more side branching?

 

[Delps8]

"add to the soil"? GIberellin controls stem growth, IIRC. I don't know how you could add something in the root zone that would "relocate" gibberellin.

Topping is very similar to FIM'ing. I top at the fourth node and then LST the branches. Seems to work pretty well but it is more labor intensive than adding something to the root zone.

Super cropping is, in my experience, a technique used to reduce the height of a cola that is unusually tall compared to the rest of the canopy. I haven't see it used in the context of inducing additional branching. OTOH, the practice of bending the apical stem is, mechanically, similar to super cropping. Supercropping involves crushing and/or bending the stem whereas bending the apical stem is just tying it down.

There's also "quadlining", AKA "mainlining", which involves topping multiple times and removal of branches from the main stem. There's a really long thread on that here on 420.

 

[Phillybonker]

"add to the soil"? GIberellin controls stem growth, IIRC. I don't know how you could add something in the root zone that would "relocate" gibberellin.

Understood.

Topping is very similar to FIM'ing. I top at the fourth node and then LST the branches. Seems to work pretty well but it is more labor intensive than adding something to the root zone.

I forgot about topping, I edited my post.

Topping weakens the structure of the plant and it can snap at the topped node in high winds or heavy rains if growing outdoors. I've done it before, and although trellis netting would probably prevent that, I won't be topping on this grow.

I wonder if FIM'ing will weaken the plant structure like topping? That's something I can't afford to happen.

Super cropping is, in my experience, a technique used to reduce the height of a cola that is unusually tall compared to the rest of the canopy. I haven't see it used in the context of inducing additional branching. OTOH, the practice of bending the apical stem is, mechanically, similar to super cropping. Supercropping involves crushing and/or bending the stem whereas bending the apical stem is just tying it down.

I probably shouldn't have said "to get more side branching" as that doesn't explain what I'm trying to do. I'm only looking to break apical dominance so the top cola doesn't get all the love at the expense of the lower buds.

 

[Sueet]

You could simply cover the top branch temporarily... tie a bag or something over it.

 

[SmokingWings]

I probably shouldn't have said "to get more side branching" as that doesn't explain what I'm trying to do. I'm only looking to break apical dominance so the top cola doesn't get all the love at the expense of the lower buds.

Years ago I read a lot of the messages about how and why to break apical dominance on indoor and outdoor plants. The general result was that it was a great way to control the height on inside plants that were starting to grow into the light. And, on outdoor plants it could be used when/if the plant was getting so tall as to attract unwanted attention.

But as a way to increase actual amounts of buds at harvest there were many who felt it did not work. The total weight seems to be the same whether the plant is allowed one major growing tip or several smaller ones.

 

[Justin Goody]

Understood.


I forgot about topping, I edited my post.

Topping weakens the structure of the plant and it can snap at the topped node in high winds or heavy rains if growing outdoors. I've done it before, and although trellis netting would probably prevent that, I won't be topping on this grow.

I wonder if FIM'ing will weaken the plant structure like topping? That's something I can't afford to happen.



I probably shouldn't have said "to get more side branching" as that doesn't explain what I'm trying to do. I'm only looking to break apical dominance so the top cola doesn't get all the love at the expense of the lower buds.

Topping weakens the plant?
Not sure I agree with any of your logic.

You don’t want the main branch to get all the love? Top your plant.
Don’t want the plant to be super skinny/tall and break in the wind? Top your plant.
Want the plant to produce many medium sized flowers instead of one giant one that’s prone to rot/pests? Top your plant.

Lots of advice here on the forum, not sure why you start a new thread every time you have a question but it’s the guaranteed way to get a bunch of strange and possibly wrong answers from people who don’t really know.

And when I quadline or hexline, I top ONCE. Not multiple times.

 

[Delps8]

Understood.


I forgot about topping, I edited my post.

Topping weakens the structure of the plant and it can snap at the topped node in high winds or heavy rains if growing outdoors. I've done it before, and although trellis netting would probably prevent that, I won't be topping on this grow.

I wonder if FIM'ing will weaken the plant structure like topping? That's something I can't afford to happen.



I probably shouldn't have said "to get more side branching" as that doesn't explain what I'm trying to do. I'm only looking to break apical dominance so the top cola doesn't get all the love at the expense of the lower buds.

Got it. Thanks for the background.

My suspicion is that if you're growing outdoors it's different issue because there's particular advantage to breaking apical dominance. The primary reason to top/fim/LST the apical stem down is to even out a canopy so that a grow light will provide a uniform light cast. When you're outdoors, that's not an issue.

The only research I've that discussed topping showed no difference in yield between plants that were topped vs not topped, though topping was not the focus of the research. I'll post the paper if that's of interest.

Re. topping ≈ weakening the plant. I've topped a little too close to the fourth node and have seen the stem split but can't say that the plant was any weaker frankly. If you leave enough of the apical stem, I'm not clear on why it would weaken the plant.

The only supplement I use is a silica supplement. Per Bugbee and Fernandez, silica is a "must have" in terms of increasing resistance to pests and disease because it makes the plant structures stronger. I've never run a test but the branches in my plants have always seemed to be been very strong. Check out the thread by @farside05 for info how to DIY a silica supplement.

One of the advantages of reducing height is that it reduces the "torsional moments" (easiest way to put it) that a taller plant induces on the root system. In addition, a taller plant tends to decrease uniformity of the levels of secondary metabolites. I've attached a paper that addresses issues with large cannabis plants. I haven't read it in some time but I believe that plants that to be an issue in very tall plants (2 meters±).

With a given number of incoming photons, yield will be the same regardless of the number of colas unless you go to extremes, of course. Before LED's, yield estimates were based on the wattage of the HPS light. Now that LED are prevalent, the yield estimate can be expressed as a function of the number of mols of light that the plant has received.

The logic behind that is that cannabis requires glucose to grow and the amount of glucose generated is a function of how much photosynthesis takes place. The inputs for photosynthesis are light and CO2. More light => more weed and more CO2 => more weed. The architecture of the plant isn't seen as a driver in the yield equation.

 

[Phillybonker]

You could simply cover the top branch temporarily... tie a bag or something over it.

Very good idea and I was going to adopt it but I just remembered stealth is an issue for me and my plants are barely hidden as it is without bags hanging off the tops.

 

[Phillybonker]

Years ago I read a lot of the messages about how and why to break apical dominance on indoor and outdoor plants. The general result was that it was a great way to control the height on inside plants that were starting to grow into the light. And, on outdoor plants it could be used when/if the plant was getting so tall as to attract unwanted attention.

But as a way to increase actual amounts of buds at harvest there were many who felt it did not work. The total weight seems to be the same whether the plant is allowed one major growing tip or several smaller ones.

Rather than quantity, I was thinking consistent quality buds right throughout the plant by breaking apical dominance. That would achieve more consistent quality, right?

 

[Phillybonker]

Topping weakens the plant?
Not sure I agree with any of your logic.

You don’t want the main branch to get all the love? Top your plant.
Don’t want the plant to be super skinny/tall and break in the wind? Top your plant.
Want the plant to produce many medium sized flowers instead of one giant one that’s prone to rot/pests? Top your plant.

Lots of advice here on the forum, not sure why you start a new thread every time you have a question but it’s the guaranteed way to get a bunch of strange and possibly wrong answers from people who don’t really know.

And when I quadline or hexline, I top ONCE. Not multiple times.

The one time I did do topping, seven out of my nine plants ended up broken at the topped node, however I did top at 4 weeks old, maybe I should wait longer before topping?

EDIT: Sorry, reading another post here I realized I'm not making myself very clear, by weakening the plant I mean it splits at the stem where it was topped.

 

[Delps8]

The one time I did do topping, seven out of my nine plants ended up broken at the topped node, however I did top at 4 weeks old, maybe I should wait longer before topping?

EDIT: Sorry, reading another post here I realized I'm not making myself very clear, by weakening the plant I mean it splits at the stem where it was topped.

The guidance I've seen, and followed, is to top after 21 days. Having a specific day number sounded. strange to me but that's how it's worked out for me.

The other criterion is to top at the Nth node. I've read "top at the 4th node" and, sure enough, that's how it's worked out.

A few times I have topped so close to the apical stem (¼" ?) and the stem has split but I only noticed the split once the plant was very mature or harvested but I haven't noticed any issues. It just grows over.

 

[Phillybonker]

Got it. Thanks for the background.

My suspicion is that if you're growing outdoors it's different issue because there's particular advantage to breaking apical dominance. The primary reason to top/fim/LST the apical stem down is to even out a canopy so that a grow light will provide a uniform light cast. When you're outdoors, that's not an issue.

When guerrilla growing sometimes the surrounding bush or vegetation can shade out the bottom half of a plant, I can't grow in more ideal places because I still got to hid the plants. So if the bottom branches can come up more towards the sun that would be a good thing in such cases.

The only research I've that discussed topping showed no difference in yield between plants that were topped vs not topped, though topping was not the focus of the research. I'll post the paper if that's of interest.

Yeah sorry I think my OP was a little misleading to what I was trying to say. I'm trying for consistent quality on all/most bud sites and I assumed breaking apical dominance would do that.

Re. topping ≈ weakening the plant. I've topped a little too close to the fourth node and have seen the stem split but can't say that the plant was any weaker frankly. If you leave enough of the apical stem, I'm not clear on why it would weaken the plant.

Yeah when I did try topping I topped at the fourth or fifth node when transplanting and this resulted in split stems.

The only supplement I use is a silica supplement. Per Bugbee and Fernandez, silica is a "must have" in terms of increasing resistance to pests and disease because it makes the plant structures stronger. I've never run a test but the branches in my plants have always seemed to be been very strong. Check out the thread by @farside05 for info how to DIY a silica supplement.

Thanks for the tip, I'll take a look.

One of the advantages of reducing height is that it reduces the "torsional moments" (easiest way to put it) that a taller plant induces on the root system. In addition, a taller plant tends to decrease uniformity of the levels of secondary metabolites. I've attached a paper that addresses issues with large cannabis plants. I haven't read it in some time but I believe that plants that to be an issue in very tall plants (2 meters±).

I'll have a read of the paper later on tonight, Thanks.

The logic behind that is that cannabis requires glucose to grow and the amount of glucose generated is a function of how much photosynthesis takes place. The inputs for photosynthesis are light and CO2. More light => more weed and more CO2 => more weed. The architecture of the plant isn't seen as a driver in the yield equation.

Gotya, understood.

 

[Phillybonker]

The guidance I've seen, and followed, is to top after 21 days. Having a specific day number sounded. strange to me but that's how it's worked out for me.

The other criterion is to top at the Nth node. I've read "top at the 4th node" and, sure enough, that's how it's worked out.

A few times I have topped so close to the apical stem (¼" ?) and the stem has split but I only noticed the split once the plant was very mature or harvested but I haven't noticed any issues. It just grows over.

I won't be topping at the 4th or 5th node anymore, it will just result in split stems again. Even when topped this girls can get to 7 ft then soon as high winds or heavy rains hit they split.

I might wait till they are a bit older and top then.

 

[SmokingWings]

Rather than quantity, I was thinking consistent quality buds right throughout the plant by breaking apical dominance. That would achieve more consistent quality, right?

Interesting question.

Sometimes quality is more than just the THC in the buds. Some might feel that fewer but larger buds with high THC is more important to their overall quality at harvest time.

 

[Phillybonker]

Interesting question.

Sometimes quality is more than just the THC in the buds.

Yeah the different cannabinoids working together can create a more pleasant effect so I've read. Some old school smokers reckon they prefer a 12% THC strain that is higher in other cannabinoids than the modern commercial strains that are breed to increase the THC for marketing reasons with no regards for the other cannabinoids.

Some might feel that fewer but larger buds with high THC is more important to their overall quality at harvest time.

I was thinking smaller and fewer buds to boost quality at harvest time.

There is a theory that I was reading about regarding quality of indoor buds verses quality of outdoor buds and it goes something like this.......

Because indoor buds are generally smaller than outdoor grown buds the trichomes are more densely packed on indoor buds compared to outdoor buds which is partly responsible for better quality on indoor buds.

I don't know how much weight that theory carries but I thought I'd put it out there.