On the topic of defoliation, I have been doing it for many years and get fantastic harvests.
We should also look at horticultural crops and what we do to then to improve yields.
In favourable conditions fruit trees set more fruit than is ideal. Fruit thinning involves removing excess fruit to improve fruit size and quality. It is carried out on apples, pears, plums, peaches, nectarines & grapes for instance. This removes "living" parts of the plant, for better yields and yes there is stress.
Many techniques in horticulture will put so stress on the plants but a healthy plant will shake this off, a unhealthy plant may not. So the question here is "are your plant normally healthy or are they normally sick and weak plants?
I think the answer for most of us is we have healthy plants.
Pruning is a horticultural and silvicultural practice involving the selective removal of certain parts of a plant, such as
branches, buds, or roots. Reasons to prune plants include deadwood removal, shaping (by controlling or redirecting growth), improving or sustaining health, reducing risk from falling branches, preparing nursery specimens for
transplanting, and both
harvesting and increasing the yield or quality of flowers and fruits.
The practice entails
targeted removal of diseased, damaged, dead, non-productive, structurally unsound, or otherwise unwanted tissue from crop and landscape plants. In general, the smaller the branch that is cut, the easier it is for a woody plant to compartmentalize the wound and thus limit the potential for pathogen intrusion and decay. It is therefore preferable to make any necessary formative structural pruning cuts to young plants, rather than removing large, poorly placed branches from mature plants.
Specialized pruning practices may be applied to certain plants, such as roses, fruit trees, and grapevines. It is important when pruning that the tree's limbs are kept intact, as this is what helps the tree stay upright. Different pruning techniques may be deployed on herbaceous plants than those used on perennial woody plants. Hedges, by design, are usually (but not exclusively) maintained by hedge trimming, rather than by pruning.
In nature, meteorological conditions such as wind, ice and snow, and salinity can cause plants to self-prune. This natural shedding is called abscission.
Then there is hedge trimming, where we cut and shape hedges with shears or electric trimmer. This is done all through the summer months and the same hedge gets trimmed every year some hedges have been repeatedly trimmed for hundreds of years.
Topiary is the same, it is constantly trimmed to keep a desired shape. As long as the plant is healthy, these too can be hundreds of years old!
The cannabis plant is tough as old boot, just look where it lives in the wild.
Furthermore our plants get treated like royalty, we give them everything we can to maximise their growth.
I very much doubt that the plants we trim and prune in our gardens, get even a little of the attention our cannabis plants do.
If we look at trees, we really can go to town on them, when we Coppice and Pollard them. In coppicing the growth is cut right to the ground in cycles (hazel coppicing is around every 4 years). The "Stool" then puts out new shoots and carries on as before. Pollarding is the same except the tree is cut around 4 feet higher, This stops cattle from browsing on the foliage. Pollards were used to feed cattle but it would be the farme who would decide when to cut back the foliage for fodder!
Mother nature also plays a part too, with wind & ice pruning.
Salt pruning is the process by which saline mists generated by
seawater are driven ashore by winds and thus over time alter the shape of trees or shrubs. The process degrades foliage and branches on the windward side of the plant that faces the body of saline water, more than it does the foliage on the landward side. The resultant growth form is asymmetrical, appearing "swept back" away from the ocean.
Strange looking plants, under constant environmental stress but they just keep living and growing.
I think there are enough journal to read through to see if, Topping, pruning, defoliation, HST,LST (these last two have STRESS in their name).
This is from Maximum Yield and it talks about GOOD STRESS for cannabis.
Good Stress
There are a variety of good types of stress that can be introduced throughout the growing cycle. Exposing cannabis plants to good stress will result in robust plants that are more likely to produce more resin and larger buds. The best plants are the ones that not only survive doses of good stress, but actually thrive on it. To ensure you are growing the best plants, it is important to cull plants at each stage of growth.
Air Circulation
Using air circulation is the most common way of stressing plants that most people already incorporate in their room for other reasons. By using an oscillating fan to keep young plants moving with forced air, you are, in effect, constantly providing small stresses to the stem of the plant which help the stem become thick and robust more quickly than if forced air is not used.
Plant Training
Plant training is the process of managing plant growth using various levels of applied stresses to manipulate the plant shape and size. These stressors alter growth by changing the plants’ nutrient distribution pathways, modulating metabolic rates, and by physically spreading the plant out laterally, making it easier to maintain an even canopy.
There are several ways of achieving this end. Some may seem extreme, but they’re worth experimenting with if you haven’t already.
Low-Stress Training (LST) is the practice of using small amounts of constant force to encourage plant branch growth in the growers’ chosen direction while opening up lower nodes to higher light intensity.
Applying this stress throughout the vegetative growth phase will provide thick stem growth, which will produce additional nutrient and water delivery capabilities during flowering. This technique is very good for increasing yield per plant while keeping the overall plant height to a minimum.
Screen of Green (ScrOG) trellising, tomato cages, and using bamboo stakes (AKA, sticking and spreading) are all great methods of applying this type of gentle stress.
Super-cropping is the method of basically breaking your plants. While this may sound extreme, it will increase your yield if done correctly. Super-cropping is the method of taking growth that is too tall for the grower’s liking and bending it in the desired direction of growth until the stem’s inside structure breaks. The intent is to break the inside while leaving the outer structure free from damage.
After a few days, you’ll notice a knuckle forming at the bend; this is a good thing. This stress increases the plants ability to deliver nutrients to the top nodes on that branch while opening up the lower branches to more light.
Topping is the most common plant control technique used in cannabis gardening. This process involves clipping off the very top shoot from the topmost plant branch(es). In doing this, the top node splits into two shoots.
This can be done multiple times through the vegetative phase to maintain the desired canopy height. For some cannabis strains, this technique will produce a nice bushy structure that provides a higher yield potential per plant. Remember, this technique should be used during vegetative growth only and is not appropriate to use during flower growth.
Lollipoping is another way of directing plant hormones to the branches or nodes of interest through defoliation. In this technique, undergrowth is periodically stripped away with the intention of pushing robust new growth to the top of the branches.
During
vegetative growth, this practice will allow the grower to direct growth in the direction of their choosing by stretching branches into the desired position on the canopy.
During
flowering, this technique is used to discourage ‘popcorn buds’—small underdeveloped flowers that are typically not marketable for flower sales—by directing growth to the top cola on each branch. It’s recommended to take advantage of this technique before placing the plant into a flowering state and between two to three weeks after the 12/12 photoperiod has been applied, depending on the genetics of the plant.
Cold Temperatures
While it may seem like a bad idea to allow cannabis plants to get cold given their ideal growing climate, it can actually be beneficial to allow the room to cool down to between 50 and 60℉ at night during the last two weeks of the flower cycle. A sequence of warm days (lights on) and cool nights (lights off) towards the end of growth mimics the natural growth cycle of cannabis plants.
In fact, many
cannabis genetics naturally flower in the colder months. Running colder temperatures boosts the plants’ metabolic system, resulting in more
resin production and a larger range of aesthetically appealing flower colors. Purple pistils are a result of cool nights at the end of a flower cycle combined with the plants’ genetic predisposition for producing purple colors.
Simulate a Drought
Drought stress is another method that is commonly used to encourage accelerated growth rates. If applied correctly, simulating a drought causes plants to react by increasing root growth rates as it prepares for supply shortages. At the same time, this increases the levels of available oxygen to the root zone. Advanced growers can push their plants’ growth much harder using this method.
However, be careful as too much of this stress is definitely a bad thing. You don’t want to see wilting plants or have the plants develop an embolism while you’re in the middle of a flowering program. Become comfortable with this technique on the small scale prior to attempting to incorporate it into a large cannabis production process.
Some of this has been copied and pasted from the internet.
My thoughts are, if you see your plant not handling something well, then stop doing it.
If on the other hand it improves the plant and/or also stops certain diseases occurring then, then this is good thing?
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These pics are from a forum post in march 2012, when the general consensus is don't do anything to an auto ever or you will f*ck it up!
Well right at the time "defoliation"of photoperiods, was the new technique on the block, and I don't do what I'm told by people who have no idea of, what can or can't be done! So I did it, as far as i know I was the first person, to defoliate an auto in forums on the internet. I also checked other forums at the time and found nothing and if people know me they know, I dig for info and then dig some more!!!! ( The thread started on 19th of March 2012 but pics were taken before then but I will go from the date mentioned.
If anyone can provide a forum post prior to that defoliating an auto, I'd like to know about it)! The post still exists!