freezeland2 said:

@Aqua Man Any thoughts on removing too much in one defoliation session? For example if an overly bushy plant is it detrimental to do it all at once or should it be a couple sessions over a few days? Great thread you got going here. Should be pretty informative to the community. I’d vote for a sticky on it.

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Aqua Man said:

General rule of thumb is no more than 1/3 in a go max and unless using it for a crop steering stressor its best done on a small continuous basis as needed imo

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freezeland2 said:

My plants are usually always a work in progress throughout the grow. Seems I take a leaf or two from each plant almost daily. I also do a heavier defoliation near the end of flower in the last week or two.

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Aqua Man said:

So let me explain defoliation in a way that will allow you to know how and when to defoliate. This is basic and wont include crop steering methods. You need to get a good base understanding and practice first imo before going all ham on advanced techniques.

Reasons for defoliation:

1. Airflow, this is to allow the leaves to transpire (breathe) well. This is super important through the entire grow. Each strain will have a different leaf to bud ratio and some strains need more then others.

2. To remove dead and unhealthy leaves that may attract pests or infections.

3. To remove older leaves no longer photosynthesizing as efficiently. As leaves get older and bigger they become less efficient. New growth is far more efficient at photosynthesis.

Now with those basics you MUST understand that its overall plant photosynthesis that matters, not just each leaf itself.

So stripping all of the older large fan leaves may seem like a good idea but its not.

Light spectrums given off not only have efficiency of the fixtures to take into account but also the plants efficiency at absorbing and converting the photons of each spectrum into energy the plant uses.

Without going to much into it Particularly green penetrates the most and while its considered an inefficient spectrum for photosynthesis at high light intensity it actually becomes the most efficient, in large part due to its penetration into the canopy increasing OVERALL plant photosynthesis…. Which also need to be considered when defoliating.

Which leaves to remove during defoliation in order of importance

1. Leaves that are dead, dying or infected.

2. Leaves that are resting on other leaves or pots etc. (largest one first) this is a common cause of infection.

3. Large older fan leaves that are blocking newer more photosynthetic growth.

4. Leaves far down in the canopy not receiving adequate light. This includes bud sites that will underdevelope.

4. Leaves far down in the canopy restricting air movement that carries away very humid air produced by plant transpiration.

5. Fan leaves growing in towards the middle of the plant tend to restrict airflow and receive little to no light so evaluating those is a good idea.

Remember while defoliating your goal is to accomplish above listed while maximizing OVERALL plant photosynthesis so dont go stripping your plant bare and letting wasted light through to the ground as some do unless you know what you are doing and the reason you are doing it.

Aqua

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freezeland2 said:

My plants are usually always a work in progress throughout the grow. Seems I take a leaf or two from each plant almost daily. I also do a heavier defoliation near the end of flower in the last week or two.

Click to expand...

Jumpingspider said:

What are your thoughts around the timing of defoliating during flower?

Would you go by the common method of day 1 day 21 of flower?

All at once or over a period of time?

Do you recommend or advise against removal of leaves at any point during the lifecycle?

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Aqua Man said:

Light spectrums given off not only have efficiency of the fixtures to take into account but also the plants efficiency at absorbing and converting the photons of each spectrum into energy the plant uses.

Without going to much into it Particularly green penetrates the most and while its considered an inefficient spectrum for photosynthesis at high light intensity it actually becomes the most efficient, in large part due to its penetration into the canopy increasing OVERALL plant photosynthesis…. Which also need to be considered when defoliating.

Click to expand...

Aqua Man said:

So let me explain defoliation in a way that will allow you to know how and when to defoliate. This is basic and wont include crop steering methods. You need to get a good base understanding and practice first imo before going all ham on advanced techniques.

Reasons for defoliation:

1. Airflow, this is to allow the leaves to transpire (breathe) well. This is super important through the entire grow. Each strain will have a different leaf to bud ratio and some strains need more then others.

2. To remove dead and unhealthy leaves that may attract pests or infections.

3. To remove older leaves no longer photosynthesizing as efficiently. As leaves get older and bigger they become less efficient. New growth is far more efficient at photosynthesis.

Now with those basics you MUST understand that its overall plant photosynthesis that matters, not just each leaf itself.

So stripping all of the older large fan leaves may seem like a good idea but its not.

Light spectrums given off not only have efficiency of the fixtures to take into account but also the plants efficiency at absorbing and converting the photons of each spectrum into energy the plant uses.

Without going to much into it Particularly green penetrates the most and while its considered an inefficient spectrum for photosynthesis at high light intensity it actually becomes the most efficient, in large part due to its penetration into the canopy increasing OVERALL plant photosynthesis…. Which also need to be considered when defoliating.

Which leaves to remove during defoliation in order of importance

1. Leaves that are dead, dying or infected.

2. Leaves that are resting on other leaves or pots etc. (largest one first) this is a common cause of infection.

3. Large older fan leaves that are blocking newer more photosynthetic growth.

4. Leaves far down in the canopy not receiving adequate light. This includes bud sites that will underdevelope.

4. Leaves far down in the canopy restricting air movement that carries away very humid air produced by plant transpiration.

5. Fan leaves growing in towards the middle of the plant tend to restrict airflow and receive little to no light so evaluating those is a good idea.

Remember while defoliating your goal is to accomplish above listed while maximizing OVERALL plant photosynthesis so dont go stripping your plant bare and letting wasted light through to the ground as some do unless you know what you are doing and the reason you are doing it.

Aqua

Click to expand...

RootsRuler said:

I've done both methods and documented growth on each along with watching and learning from some VERY highly skilled growers.

Picking off leaves as needed throughout will certainly lessen the stress the plants will go through but I noticed less explosive growth spurts vs doing a hard defol.

What most of the pro growers I've worked with do is to move fan leaves out of the way if they are impeding light and only cut them off a week or a little less before flower flip. One grower told me he does this to give the plant a chance to recover from the shock before the plant needs to concentrate its energy on flowering so I would imagine this is the same reason others do it. Obviously if there were fan leaves that were huge and blocking major bud sites they would get cut off but, for the most part, they were pretty judicious in removing leaves in Veg. When I worked for Jungle Boys in L.A. their defol rule of thumb was to lollipop everything 12" under the canopy and defol every other leaf in the sweet zone. They did this a week before flower flip. They were running Gavita DE1000 Pro's for lighting so they had great canopy penetration.

Of course the other part of the equation is that they also start to phospho load a few days prior to defoliating to kick start the flower process. Not so much to make them toxic but certainly enough to push them hard. Once the plant recovered flower formation came on quickly for the first 3 weeks then just thickened and hardened while continuing to swell in size for the remainder.

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Aqua Man said:

So let me explain defoliation in a way that will allow you to know how and when to defoliate. This is basic and wont include crop steering methods. You need to get a good base understanding and practice first imo before going all ham on advanced techniques.

Reasons for defoliation:

1. Airflow, this is to allow the leaves to transpire (breathe) well. This is super important through the entire grow. Each strain will have a different leaf to bud ratio and some strains need more then others.

2. To remove dead and unhealthy leaves that may attract pests or infections.

3. To remove older leaves no longer photosynthesizing as efficiently. As leaves get older and bigger they become less efficient. New growth is far more efficient at photosynthesis.

Now with those basics you MUST understand that its overall plant photosynthesis that matters, not just each leaf itself.

So stripping all of the older large fan leaves may seem like a good idea but its not.

Light spectrums given off not only have efficiency of the fixtures to take into account but also the plants efficiency at absorbing and converting the photons of each spectrum into energy the plant uses.

Without going to much into it Particularly green penetrates the most and while its considered an inefficient spectrum for photosynthesis at high light intensity it actually becomes the most efficient, in large part due to its penetration into the canopy increasing OVERALL plant photosynthesis…. Which also need to be considered when defoliating.

Which leaves to remove during defoliation in order of importance

1. Leaves that are dead, dying or infected.

2. Leaves that are resting on other leaves or pots etc. (largest one first) this is a common cause of infection.

3. Large older fan leaves that are blocking newer more photosynthetic growth.

4. Leaves far down in the canopy not receiving adequate light. This includes bud sites that will underdevelope.

4. Leaves far down in the canopy restricting air movement that carries away very humid air produced by plant transpiration.

5. Fan leaves growing in towards the middle of the plant tend to restrict airflow and receive little to no light so evaluating those is a good idea.

Remember while defoliating your goal is to accomplish above listed while maximizing OVERALL plant photosynthesis so dont go stripping your plant bare and letting wasted light through to the ground as some do unless you know what you are doing and the reason you are doing it.

Aqua

Click to expand...