have always used that “hollow stem” to judge my harvest - found that if you get a 50/50 (stem/hollow) or more plant was ready to be harvested . when we are talking about stalks we are talking about up-take - the more hollow the less up-take
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Use em as a doobie crutch. 
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My plants have hollow stems if I don’t add micronutrients to my water, and full stems if I do. My bet’s on it being nutrient deficiency most of the time when people on here run into it; even if it’s a genetic trait of plants grown for fiber, the genetics we’re working with have been bred away from that for generations.
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Fascinating observation! It’s great if you to share them. I believe the theory or hypothesis about hollow stalks being attributed to hemp may have something to do with the amount of time it takes to achieve a given height. I’ve read that the hollow stalks can grow taller quicker than the more solid ones, so if growing for the fibers it may have something to do with it. I don’t think people back in the day classified hemp as it relates to total THC percentage. I think it was more about utility and some cultures used the fiber only while other cultures and civilizations utilized the medicinal attributes of the plants to varying degrees. Much love
My money says the same. 
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That’s a whole debate on itself, the AK47 (not the photo) by example is know both to kick asses but also to produce hollow trunks (with very low fiber content) and i just get the confirmation that it don’t changed in culling an half dozen of males.
I didn’t say it’s impossible for someone to find a potent plant that has hollow stems… just that most of the time, if people here are seeing hollow stems it’s probably gonna be micronutrient deficiencies. At the very least, anyone growing hollow-stem plants who hasn’t tried supplemental micros should try them before just assuming they’re supposed to grow that way because they’re fiber plants. If they don’t change, maybe you have a plant that legitimately has that genetic trait, but most probably don’t.
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I got your point don’t worry, i quoted the AK47 (actually growing here, and useful for the subject) to give a counter-example of my #203 post in up. To show that it’s a bit more complicated sometimes that just culling all hollow plants blindly (by example).
The trap i see in your position is to minimize your footprint in this expression, specially if you play on the leverages of the said expression to “correct” it before evaluating the specimen. My example is awful but it’s like considering the “fluffy” quality of a sativa hybrid not genetical, because it answer well to PGRs (while others don’t).
I’ve also already screened lines for nutes uptake that have grown fully in heavy deficiencies (overall) and produced plain trunks in a stable way (Orange Bud DP, some others skunks and a bunch of sativas and hazes hybrids). I ear your advise, but i’m forced to return it in the reverse sense. It’s a vicious subject by definition anyway.
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I’ve never once had a hollow stemmed plant. I’ve been growing for 20 some odd years. 
. I only grow indica plants. And never have seen this first hand.
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I agree 100%
Those that do not try to correct the deficency are probably not getting the most out of those hollow stem plants.
I find it funny that some say…Naw! that won’t work and they never even try to fix the issue. 
You can lead a man to knowledge but you can’t make him think… 
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Boron is the most important Calcium synergist.
Boron and calcium work together to improve plant strength by reinforcing cell walls so reducing the effects of nutritional disorders such as tip burn in cauliflower, hollow stems or internal browning.
While calcium is called the trucker of all nutrients, boron is said to be the steering wheel because it is responsible for “steering” calcium into the plant . For this reason, boron, although needed in only very small amounts, is crucial to the uptake of calcium.
Boron and calcium work together to improve plant strength by reinforcing cell walls so reducing the effects of nutritional disorders such as tip burn in cauliflower, hollow stems or internal browning.
For calcium, the desired concentration is roughly 650 to 900 ppm, and for boron the desired concentration is 25 to 50 ppm. Because calcium and boron are difficult to translocate from the canopy to the root tissues, it is always desirable to apply these elements to both plants and soils.
shag says…
For cannabis, this may or may not be too much boron depending on how much calcium has been provided.
Healthy plant development requires careful, constant nutritional supplementation.
Cultivating healthy plant growth is analogous to laying a foundation—not only must you have a constant supply of concrete mix, but the stabilizing rebar must be set at a constant ratio. If you omit the rebar, the foundation can still be laid, but it will have weak spots that become apparent over time, and which will jeopardize your entire construction project.
Calcium and boron are the rebar of the plant.
Calcium, potassium, and nitrogen concentrations in both the soil and plant can affect boron availability and plant function, the calcium:boron (Ca:B) ratio relationship being the most important. Therefore, soils high in calcium will require more boron than soils low in calcium.
It appears that Ca increases the B requirement of plants due to similarity in function (Valmis and Ulrich, 1971;
Golakiya and Patel, 1988)
Cellulose, hemi cellulose and pectin take Ca to form. B and Si increase the delivery of Ca
If you never get enough Ca you might not know
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So, if I was mixing my own salts, what elemental ppm of B should I shoot for? Or better yet, what is the proper ratio of Ca:B?
Note:
This can be subjective.
Critical Role of Calcium and Boron in Plant Health and Development.
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I asked chat GPT to telll me about that article like bugs bunny 
"Ah, what’s up, doc? So, picture this: you got these herbaceous plants, right? And inside their stems, there’s this thing called pith, kind of like a storage unit for carbon. Now, sometimes this pith starts diggin’ its own grave, so to speak, and hollows out the stem. We call this pith autolysis - fancy term, huh?
Now, here’s the carrot in the stew: we got this theory that says when these plants are in a growth spurt and need extra energy, they start munching on that pith to keep going. Think of it like a snack break for the stem! So, the faster the plants grow, the more hollow their stems become.
But wait, there’s more! When we give ‘em a little something-something called GA3, it’s like giving Popeye his spinach - they grow even faster and chomp down on that pith even more! And if they’re not gettin’ enough light, well, it’s like they’re on a diet and they start hollowing out even faster.
Now, here’s the kicker: when these plants start making babies (yeah, I’m talking flowers), they go all-in and hollow out their stems big time. It’s like they’re splurgin’ on carbon for the next generation!
But don’t worry, doc, we found out we can keep those stems from going hollow by giving 'em a little extra carbon in the air. It’s like giving 'em a breath of fresh air - literally!
So, that’s the scoop, doc! Plants gotta eat, grow, and make babies, and sometimes that means chomping down on their own storage space. Ain’t nature a hoot? "
It makes it sound like the Crime Pays But Botany Doesn’t guy is reading it.
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To add my 2 cents. I think there is something that plays huge role here that never really gets talked about.
It plays plays a huge role in many aspects of growing and all life in general.
Its metabolism. We see plants stay smaller in smaller pots and yes there is a million reasons for this but when it comes down to it, its because the plants metabolism is slowed.
Its why you can grow the biggest plants while chasing vigor.
Anyway i can make an entire post on plant metabolism and I will but for the sake of the post.
I would like to say i have noticed plants with slower metabolism have thicker stems.
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You @PsillyRabbit trips are for kids. 
I love that explanation, super easy to understand.
That explanation seem to say additional co2 is the fix.
I don’t use co2 but I did go from hollow stems to solid stems without co2.
I guess what I am saying there seems to be more than one way to fix it.
If you have the time…
Can you ask chat GPT about the calcium boron silica synergy and if those things can be used to correct hollow stems.
…This combination can help plants develop stronger and less hollow stems. However, the effectiveness of these elements in correcting hollow stems may depend on various factors such as the specific plant species, growing conditions, and the severity of the issue.
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