Lets learn about Phytohormones together, how they work and how we can use them in our gardens

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Phytohormones: What Are they?

1. Auxin
2. Cytokinin
3. Gibberellins (GAs)
4. Abscisic acid (ABA)
5. Ethylene
6. Brassinosteroids (BRs)
7. Jasmonic acid (JA)
8. Florigen
9. Strigolactones (SLs)
10. Salicylic acid

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Let me start by saying that (most) hormones don’t have a direct effect on plants. What plant hormones do is activate a signal cascade resulting in the activation of genes which give a response that is observed.

Plant growth and development involves the integration of many environmental and endogenous signals that, together with the intrinsic genetic program, determine plant form. Fundamental to this process are several growth regulators collectively called plant hormones or phytohormones.

Changes in concentration or usage of Phytohormones have differing effects, thus the multiple effects seen from one hormone depends on the application method and strength.

This is all contingent on the cultivar/strain’s particular genetic limits and stage of growth (Clone, teen, veg, pre-flower, flower initiation, bud set, bulk up ect.)
The effects of a hormone on a plant often depend on the stage of the plant’s development.

Yes, you can turn a fluffy strain into a dense strain!
But
It is best to start with your preferred genetic traits and maximize their potential with the environment and other factors that we have available to us.

All comments and questions are welcome.

Let us all work together on this and see where it goes… :star_struck:

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Lets crush it!

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@shag you are right that hormones can have individual effects, thats why we use them as pgrs. But that is a simplistic view and doesn’t get to the complexities of physiological control.

I’m a big systems management and emergent properties guy, I think if we looked at plants as systems then hormonal control and effects gets much more complicated. And the interactions between hormones. And hormone precursors and enzymes and transportation.

I think the answer for the best use then will consider relative concentrations of hormones and precursors. This is still relatively new research and it has some exciting implications for how relationships with microbes are formed and persist. Really excited to be able to update this when more info is available and build off our hormone mode of action knowledge!!

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How do microbes affect Phytohormone levels in plants?
Some of these phytohormones such as cytokinin, gibberellin, salicylic acid, auxin, and ethylene are also produced by plant growth-promoting bacteria (PGPB).

Some microbes are able to produce indoleacetic acid (IAA) from L-tryptophan.
Pseudomonas have also been reported as producers of Cytokinin

What other microbes are known to do this?

The production of IAA has been reported in various genera of PGPB including …

  1. Acetobacter
  2. Acinetobacter
  3. Azospirillum
  4. Arthrobacter, Azotobacter
  5. Bacillus
  6. Bradyrhizobium
  7. Burkholderia
  8. Herbaspirillum
  9. Klebsiella
  10. Mesorhizobium
  11. Paenibacillus
  12. Pantoea
  13. Pseudomonas
  14. Rhizobium
  15. Rhodococcus
  16. Serratia
  17. Strenotophomonas
  18. Streptomyces
  19. Rouxiella

Agrobacterium tumefaciens is up for discussion.

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Effect➡️ affect.
An effect is an outcome, where an affect is how something changes an outcome :stuck_out_tongue_winking_eye:

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Auxin

Auxins are produced in significant quantities in the upper growth regions of plants, promoting cell elongation. Auxins travel from the shoot tips to the base when the plant is actively growing, playing a role in the formation of plant roots.
IAA is an auxin in its natural state. Synthetic rooting hormones contain compounds such as IBA typically range in concentration from 1000-10,000 ppm.

When cuttings are taken, and dipped for rooting, here’s part of what happens: The plant stops growing stem tissue. The cells that have been developing but have not yet been dedicated to any specific type of growth (i.e. stem development) are stimulated by the auxin such as IBA to become roots.

These cells are now set to grow roots, and will further multiply and develop to produce a healthy root system, which will develop hormones that influence the upper development of the plant. Synthetic auxins sprayed on tomato vines will allow fruit to develop without pollination. Auxin that is usually produced by the seeds has been replaced, so no seeds will develop.

An overdose of auxin will actually inhibit cell elongation, because the plant will produce another hormone to try and balance the act. When applied to seeds, auxins also help to promote femaleness in dioecious plants (plants having females and males). The concentration of auxin is usually highest at the main growing point of the plant, suppressing lateral/side shoot growth.

Growers have often pinched the tips of the plants in order to promote extensive branching and to keep plants short and sturdy. Bending and tying the growing point downwards will also have a similar effect without damaging the concentration of auxins within the plant.

Types of Auxin

  1. IAA is the most natural of the 3
  2. IBA is in the middle
  3. NAA is the most unnatural of the 3

Most of us use auxin for quicker rooting results.

These products contains IBA and are approved for use on hemp by the EPA.

CLONEX ROOTING GEL
K-L-N ROOTING CONCENTRATE made by DYNA-GRO
EPA Registration Number: 87394-3
IBA (INDOLE-3-BUTYRIC ACID), 1-NAPTHALENEACETIC ACID

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Cytokinin

Cytokinin production in roots was shown to be essential for female sex determination in hemp plants.
(This means you can trim the roots to initiate a sex change from female to male.)

Shag’s best guess at how to use cytokinins effectively!

Cytokinins used at high ppm/mg per liter during cloning will prevent callus from forming roots and tell the plant to make shoots.
I don’t generally recommend cytokinins for clones unless you are trying to promotes callus induction.

You need to start low with just established clones.
Cytokinins can inhibit downward root growth.
At high levels cytokinins can inhibit root growth in cannabis.
At the correct levels it will encourage lateral root growth while allowing for normal root length.(tiny root hairs)
As they get bigger you give them a very small increase in dosage or slowly increase the ppm in medium or in the REZ.
That is if you are looking to optimize root growth.

But remember this is strain/cultivar subjective.
Shorter plants need less so as to maintain fast growth while stretchier strains need more to slow growth just enough!

If you want to change the shape of the plant (shorten it) then a higher PPM/mg/l is required.

Wait 5-7 days after application this will give the plant a chance to react.
I recommend you apply small amounts in the rez. and then use frequent foliar sprays for best results.
After you use a spray wait a few days, if you don’t like the results you can spray again, I suggest low doses more often to get the effect you are looking for rather than high doses less often.

Bud cycle is another story.
At the right time and PPM it will give you a faster bud set!
I know if you don’t get the timing right and you get the ppm’s/mg/L too high it will stop vertical growth and decrease yield especially when the plants have been topped!

These instructions are for using cytokinins by themselves.
I personally think they work better in a synergistic manner with auxin and brassinoloid, but then PPM must be recalculated.

Types of Cytokinin

1. Benzylaminopurine/BAP/Ba-6
2. Furfurylaminopurine/Kinetin
3. Adenine

Benzylaminopurine is NOT water soluble. Use KOH Solution to dissolve.
Can be used in the vegetative growth or flower stages.
Can be used in drench feeds, hydroponic systems, soil, coco, soil-less mediums, and foliar sprays.

Foliar Spray: Once every 7-14 days

I feel Kinetin and Adenine are the best choices for use with cannabis.

Kinetin is a synthetic cytokinin class plant growth regulating phytohormone, altough it has been shown to exist naturally in the DNA of cells of almost all organisms tested so far, including human and numerous plants.

Kinetin is currently sold commercially under the trade name “Bonide Tomato and Blossom Set Spray”, and can be used to increase yields of various fruits and vegetables, produce seedless fruits, and increase ‘budding’ of various herbs.
Kinetin is also widely used in producing new plants from tissue cultures.

I find a single spray of 100-300ppm BAP in mid-veg increases branching significantly. However, it also seems to stall the plants for about a week. And too much branching can be bad depending on the strain - it results in a ton of buds but they just don’t get as big. I’ve gone back to normal topping and pinching now because it’s just a bit easier to control the structure of the plant that way. If using a branching hormone, I would suggest NOT also topping - this creates just way too many branches and results in the small bud problem. Use one method or the other.

And FWIW, potassium hydroxide for dissolving BAP has been the least phytotoxic solvent thus far. DMSO is a better solvent and increases absorption, but I have had mixed results regarding phytotoxicity and DMSO.

It is postulated that the effect of DMSO may result from a modification of gibberellic acid gradients or their distribution.

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjH0ojnx-KDAxXzg4kEHTBwDLAQFnoECA8QAQ&url=https%3A%2F%2Fir.library.oregonstate.edu%2Fdownloads%2Fpc289n11r&usg=AOvVaw0186AEdh3jW1uZ3osX47xx&opi=89978449
These product contain Kinetin and are pproved for use on hemp by the EPA.

A foliar spray of 50 to 100 ppm of 6-BAP seemed to induce 1 week head start on bud set cut down the stretch a tad.

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Gibberellins (GAs)

The biologically active gibberellins are GA1, GA3, GA4, and GA7

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Abscisic acid (ABA)

ABA treatment increased THC concentration in both leaf and female flower tissues (Mansouri et al.2009).

Exogenous GA application induced male flower formation on female cannabis plants, which was inhibited by ABA.

You would think that if your female plant was expressing partially male, a spray of ABA would keep the plant from expressing male?
But ABA may inhibit flowering of any kind.

Previous studies demonstrated that ABA alone did not affect flower sex determination, however, ABA inhibited IAA induced female flower formation and impaired GA induced male flower development (Ram and Jaiswal 1972; Galoch 1978).

I feel ABA (and ethylene) are very good choices to temporarily rid your garden of intersex plants.

Just spray and the balls go away…that simple. :rofl:
I have personally used Ethylene for this, the science seems to indicate that ABA is a good choice with similar results.

My suggestions are either one should work fine, but if you spray both in rotation 3-4 days apart that may speed things up or make the process more efficient.
I also suggest using Ethylene early in the grow and ABA late.

More investigation is needed but using ABA late may increase secondary metabolite production in cannabis.

I suspect it may be the active ingredient in products like https://cropsalt.com/products/cak

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Abscisic acid is a hormone that induces stomatal closure during water stress (see Chapter 23). (After Hsiao 1979.)

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Ethylene

I usually only use it if I see any balls in flower, some strains are prone to it. I use 400pm florel ph’d to 4.0-4.5 and foliar sprayed once at day ~15 if I see any balls/brown pistils and then again a week later at day ~21 to make sure.

Ethephon has the following very obvious and significant effects:

  • reduced internode space and shorter plants after flip (plants stop stretching around day ~17 instead of day ~22). This is perhaps to most significant effects since it leads to much denser bud structures.
  • earlier bud maturation. The buds start more dense and solid. Instead of being airy and then “filling in,” they start dense and expand out.
  • Earlier terpene production. My room smells like day 50 at day 20.
  • Some premature leaf yellowing (on older shade leaves). This is a side affect of the hormonal ripening response.
  • Early and strong coloration
  • Suppression of any seeds and nanners. Lifesaver if using an unstable strain.
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Brassinosteroids (BRs)

Brassinolide (BL)
Wild-type tobacco treated with BL exhibited enhanced resistance to the viral pathogen tobacco mosaic virus (TMV), the bacterial pathogen Pseudomonas syringae pv. tabaci (Pst), and the fungal pathogen Oidium sp
https://onlinelibrary.wiley.com/doi/full/10.1046/j.1365-313X.2003.01675.x

Usage of Brassinolide:

Brassinolide is fully water soluble.
Can be used in the germination of seeds, or propagation of clones.
Can be used in the vegetative growth or flower stages.
Can be used in drench feeds, hydroponic systems, soil, coco, soilless mediums, and foliar sprays.

A foliar spray of 0.005 - 0.01ppm BR is a good starting point.

In my opinion, BR or BL/Brassinolide is best used with a Cytokinin.
These are my 2 favorite hormones. :slightly_smiling_face:

For a general starting point I recommend using >0.01 ppm brass and 100ppm bap 1 week before flower.
Switch lights
Wait 3-7 days if you see too much stretch then add up 100 ppm
BAP alone in a spray depending on your cultivar/variety.
When stretch is done spray with >0.01 ppm brass and100ppm bap again.

Brassinosteroids may cause a crop to ripen prematurely, this could be useful for a finishing product.

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Jasmonic acid (JA)

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Florigen

Florigen, or flowering hormone, is thought to be a protein insulin particle that controls or enhances the flower initiation process in plants. These florigens are made in the leaf and are found in the bud’s stem and root apical meristems and growing tips.

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Strigolactones (SLs)

The Unmasking of a New Branching Hormone

Strigolactones are a group of terpenoid lactones that act as a host-derived signal in the rhizosphere communication of plants with arbuscular mycorrhiza and root weeds. They also occur as endogenous plant hormones regulating shoot branching in plants. All natural strigolactones contain a tricyclic ring system connected to a butenolide via an enol ether bridge. Most of the germination stimulants identified so far are strigolactones.

Shoot branches grow from axillary buds that arise in leaf axils. Auxin and cytokinin have long been known to be important plant hormones involved in regulating the outgrowth of axillary buds into branches. Recently, thanks to the use of branching mutants in several species, we now know the identity of a third hormone group, strigolactones, involved in this process.

http://5e.plantphys.net/article.php?ch=&id=486

Dizzlekush says:
Strigolactones initiate germination of AM/Arbuscular mycorrhiza
increase mitochondrial activity and density of AM, increase cell proliferation of AM (growth), and promote pre-symbiotic branching of AM. This naturally occurs in the rhizosphere as a/the plant starts lacking nitrogen and/or phosphorous and exudes specific strigolactones into the rhizosphere, or when certain environmental cues happen. The entire process usually unfurls in a 4-6 week period. One could essentially sidestep this whole 4-6 week natural forming of symbiosis by doing this process yourself, as i previously mentioned, saving your plants 4-6 weeks of work/waiting…

Again this is all just theory, im not aware of strigolactones ever being concentrated or synthesized and utilized in any sort of experimentation. We’re pretty slow when it comes to strigolactone research ATM. We’ve known about them for over 15 years and have thought they were detrimental to plant growth for more than half the time we’ve been aware of them (because they were exuded by witches weed). Only ~7 years ago we discovered that they had beneficial aspects , and only 4 years ago did we find out that they are one of the essential groups of phytohormones in all (terrestrial at least) plants.

Master hormone controls plant growth

A single hormone co-ordinates how a plant grows in response to the environment, researchers have found.

Plant molecular biologist Dr Phil Brewer, of the University of Queensland, and colleagues, report their findings about a chemical called strigolactone

Stem thickening
Brewer and colleages have found that when strigolactone levels are high, not only does this stop buds from turning into branches, but it also thickens up the main stem.

This makes sure that a plant growing tall to reach the light, also has the structural strength to do so.

“We now think that this is a hormone that co-ordinates a response for the whole plant,” says Brewer. “It’s not just about the branching, it’s also about other parts of the plant. It’s about optimising its growth.”

He says that for many years, scientists thought the thickening of stems was controlled by a chemical called auxin, but these latest findings challenge this.

“This is a breakthrough for us because it shows that auxin works through strigolactones to do this job,” says Brewer. “It’s a big change in the dogma of the field.”

Brewer says he and collaborators are also finding strigolactone influences other parts of the plant too.

When nutrient levels are low, strigolactone levels rise and this stimulates production of root hairs and beneficial mycorrhizal fungi, which both help increase uptake of nutrients.

On the downside, some parasitic weeds have hijacked this system, says Brewer.

Strigolactone exuded from the plant roots signals to the seeds of these weeds its time to germinate and invade the nearby host plant.

Brewer says it’s possible that strigolactone could be fed to trees that are being grown for timber to make them grow strong, tall and straight.

"It would also potentially make the trees more efficient at taking up nutrients,

Strigolactones fine-tune the root system
https://www.google.com/url?sa=t&rct…=D66T-r2Atjnm6gAOSouLYw&bvm=bv.57799294,d.b2I

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Enzymes are not the limiting factor.
Auxin comes from tryptophan via a flavin bearing monooxygenase. Both tryptophan and enzyme are produced by nitrogen, and most grows do not convert nitrogen to aminos and enzymes efficiently.

Tryptophan makes you sleepy! And so does glycine I think! Entourage aminos! Lol

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Great post @MAKE-BELIEVE-WEED !

In cases where resources (nutrients) are at a surplus (typical of hydroponic situations, roots directly in nutrient solution) then the limiting step in production becomes enzymatic activity rate. This is why there are upper limits to what CO2 supplementation can achieve. Depending on genetic make up, plants may be able to produce more enzymes and so the rate can go up relative to other genotypes

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Hormone synergies

  1. Gibberellin and jasmonic acid
    Gibberellin and jasmonic acid together will have a synergistic effect on both trichome number and density, Jasmonic acid is also responsible for increasing THC within the trichome.
    GA-3 increases the size of the trichome/resin glands allowing MeJe to increase THC & terpenes within them.
  1. ABA, Methyl Jasmonate and Sugar

The use of s-abscisic acid (S-ABA), methyl jasmonate (MJ), glucose, sucrose and fructose to raise the level of cannabinoids and terpenes (flavor and scent molecules) in the Cannabis Sativa plant.

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  1. SA, methyl jasmonate (MeJA), and GABA
    SA, methyl jasmonate (MeJA), and GABA produces changes in the accumulation of the two major cannabinoids, cannabidiolic acid (CBDA) and Δ9- tetrahydrocannabinolic acid (THCA), in leaves and inflorescences of a medical cannabis variety. MeJA at 0.1 mM increased the CBDA content in inflorescences by 15.6%, while SA and MeJA at 0.1 mM increased CBDA and THCA accumulation in leaves by up to 57.3%.
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Hormone precursors and enzymes

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D-I-Y Clone gel and rooting solutions ect.
(More formulations coming soon)

How To Dissolve Indole Butyric Acid:

Dissolving Using Isopropanol:
Indole Butyric Acid readily dissolves with Isopropanol (Isopropyl Rubbing Alcohol). Using 70% will work dissolve IBA just fine, but the with the lower the Isopropanol purity, the lower the upper limits in usefulness… When using Isopropanol, at roughly 500 PPM, when diluting into water some of the IBA will turn back into crystals. To counter this, soaking your subjects for longer durations should typically achieve the same results. Also, high PPM dissolved alcohol solution can be brushed directly onto plant materials.

Dissolving Using Methanol:
High purity methanol will dissolve IBA just the same, but it reduces the upper limits above by allowing the creation of solutions more in the 1000PPM range.

Dissolving Using Ammonia:
One scoop of IBA can be dissolved in less than half a spoon full of ammonia.

Dissolving Using Lanolin Paste:
Oil or grease bases, such as Lanolin paste, are made by stirring the growth substance into the molten lanolin and then allowing it to cool. To make a 5,000 PPM paste, dissolve 1 gram of IBA into 200g of lanolin and thoroughly mix.

How to Dilute & Mix Indole Butyric Acid:

Diluting Indole Butyric Acid In Water:
Slowly pour the dissolved IBA into your water solution ‘broth’, not the other way around. You should stir the water at the same time, or simply ‘rock’ the water vessel once to create a back and forth ‘wave’ that should last until you’re done pouring.

Turning Pure Indole Butyric Acid Into Rooting ‘Compound Powder’:
To make a 10,000 PPM ‘rooting compound’ dissolve 1 g of the substance in 40 ml of alcohol, and stir into 100g of talc to form a smooth paste and then continue to stir the paste until it dries into a fine dry powder.

Turning Pure Indole Butyric Acid Into ‘Rooting Gel:
One commercial gel product (Clonex) contains .3% IBA, 1.2% 2.hydroxyethyl cellulose (as the viscosifier), and 98% water (to achieve a 3000PPM product).
Gelatin should work theoretically, but being animal based spoilage and bacterial infestation are a major concern.

It’s worth noting that KY Jelly has used hydroxyethyl cellulose as its main ingredient, as well as nonoxynol-9.
Currently, it uses methyl cellulose with carboxymethyl cellulose as a secondary ingredient.
Any of these products should work. Glycerine can be used, potentially, but as in KY NG antiseptic and preservative additives such as chlorhexidine gluconate, glucono delta-lactone, methylparaben and sodium hydroxide should be considered.

I hope to discuss alternate choices for hydroxyethyl cellulose in the future.
I like to add IBA and NAA to my clone gel ect.
IBA works best when used with NAA at 2:1 or 3:1 ratio IBA/NAA

For a water soluable version you can use IBA-K.
IBA-K Percentage content 98%
Which is aprox. K18% IBA 80%

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Are these products related to the nasty PGR’s we know from years gone by? Can these be applied to cannabis with positive results?

Loving this thread!!!

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