When do you P/K boost?

[Ca++]

The studies have confirmed 11.5ppm to be enough to grow Bugsbee/Buildasoil/Kis/youtube grade weed.


But if you want to grow quality, more like 90ppm. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8320666/

Careful which experts you follow. Most don't know weed.

11.5 would be below the 15ppm of sufficiency. A target just short of 30ppm has been seen in other studies, which is more like addequate, than sufficient. . Which is accepted by Bugbee, though I think he goes a little higher. I have it somewhere.. Perhaps 60ppm like myself. Though I have also been boosting that to 90ppm myself in early flower, just to get some size to everything. Your study doesn't really say 90ppm is right, and points to the fact weeds at it's most potent around 30ppm. Any more, and flower weight is increasing, but the dilution effect is reducing it's strength. 90ppm is that shop weed that tastes chemically, and isn't what it could be. Though as you say, we should choose who we listen to, or rather, I believe we should listen to everybody, and make our own decisions based on all evidence available. We know that's where most people fall down though. As a race, we are sheep, and so thinking for ourselves is a big ask.
If you feel 90ppm is the ticket, wait for the 120ppm test. We already know the result, if we can see the data for what it is.

 

[Solidopc]

Bag appeal is not the mission, at least not for the selling. It's mostly in my mother's cancer and feco oil helps. So I don't know what if any difference is in store. But if it helps my mum. I'm cropping till I get her some real medication.

 

[Old Uncle Ben]

.... It happens if I let the soil dry out, so apparently chelated food is really (edit: NOT) good if you have to restore the soils retention power.

There's your problem, salinity rises as the soil dries out. For starts, why would you ever let the soil dry out? Keep it moist at all times and when you water make sure you get a good run off. The soil needs to be thoroughly drenched with no dry pockets or channels.

You'll be leaching excess salts out of the pot and then to add to your confusion or speculation if you will, ask yourself "how much fertilizer do I add now and which bottle do I grab?" There in lies the benefits of balanced slow release foods like Osmocote. It removes all the guessing.

Seems you're caught up in a vicious cycle. Tis the norm around these parts.

I'm germing some indicas again - Kwik (Real) Seeds Afghan mix and their old school1990 Master Kush X Afghaan 90. My drill will be a repeat of what I did on my last indica garden cause it served me well. I'll be using MicroKote painted pots (to increase root mass, efficiency via root pruning) and feeding with Osmocote 15-9-12 start to finish. Background is a mango tree, my real passion these days.

Good luck,
Uncle Ben

 

[Old Uncle Ben]

11.5 would be below the 15ppm of sufficiency.

Relative to what? P doesn't work "its magic" in a vacuum. "Though I have also been boosting that to 90ppm myself in early flower, just to get some size to everything." That size stuff is the function of leaves, photosynthesis ya know.

Like I wrote many years ago, "how much phosphorous is enough to support good flowering?" That goes with ALL of the essential elements as they do not act alone but rather in tandem for healthy tissue production and maintenance. For example, if you have, or induce, a deficiency of iron and/or zinc you'll have leaf chlorosis which will compromise photosynthesis, chlorophyll production and efficiency. Seems with all this hoopla folks have forgotten what makes a plant tick. They're more interested in drumming up some study without exploring and understanding all of the caveats.

Here's some science:

Phosphorus nutrition has long been a focus in cannabis cultivation. Growers often supply plants with relatively high P concentrations (up to 200 mg L–1) during the flowering stage based on a belief that high P promotes flower development. However, there is little evidence to support this practice. A recent study found that cannabis plants in the vegetative stage supplied with 100 mg L–1 P performed similar to those supplied with 30 mg L–1 P (Shiponi and Bernstein, 2021). High P concentration in the nutrient solution creates a situation where environmental pollution from excess P is more likely. Clearly, the practice of supplying cannabis with high concentrations of P needs to be evaluated.

....and...

Many commercial cannabis cultivation operations currently use fertiliser formulations that contain very high levels of P (more than 200 mg L–1 P in some cases). This practice is based on anecdotal evidence that P enhances inflorescence production. These concentrations are much higher than the optimal rate of 60 mg L–1 P found in our study, and at the higher range could cause reduction of both plant growth and inflorescence yield.

I did a cursory look at that study, seems to be a good, solid read. Covers N above that paragraph on phosphorous. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8635921/

And the cannabis specific food hawkers march on targeting noobs with their typical feel good brainwashing --> This mineral fertilizer brand, Hesi, has created Phosphorus Plus, a product designed to grow bigger buds and obtain amazingly thick flowers from your cannabis plants. It gives your plants an extra dose of phosphorus and potassium during the end of the flowering period. This additive should be used alongside Hesi’s flowering complex, which is a complete flowering base that contains the perfect amount of macro and micro-nutrients for cannabis plants. https://www.growbarato.net/blog/en/...s-on-cannabis-plants/#Phosphorus_Plus_by_Hesi



UB

 

[Old Uncle Ben]

Bag appeal is not the mission, at least not for the selling. It's mostly in my mother's cancer and feco oil helps. So I don't know what if any difference is in store. But if it helps my mum. I'm cropping till I get her some real medication.

Sorry to hear about your mum, hope she pulls thru OK. Feco oil, what's that? I assume you're in the U.K. If in the states you might want to try this CBD/CBG tincture for nausea and inflammation control. I just ordered two large bottles. One for me and one for my girlfriend's sister who's going thru a miserable bout of chemo. I buy their products with a 60% off disability discount, check out that program. https://www.lazarusnaturals.com/cbg-cbd-oil-tincture-full-spectrum#205=5493&188=5442

Have also spent hours browsing Mandala's seed lines. They offer strains that are high in certain cannabanoids like CBD, THCA, CBG. Although I haven't grown it out I have a strain high in CBD called Dancehall.

Good luck,
UB

 

[blondie]

@Old Uncle Ben thanks for posting this.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8635921/

Well worth the read. Many pearls of wisdom in that article. This was one of my takeaways. Think you need more cal mag? Maybe not...

A recent study found that high K supply decreased concentrations of Ca and Mg in cannabis leaf tissue, indicating antagonistic relationships between these positively charged ions (Saloner et al., 2019

 

[Old Uncle Ben]

@Old Uncle Ben thanks for posting this.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8635921/

Well worth the read. Many pearls of wisdom in that article. This was one of my takeaways. Think you need more cal mag? Maybe not...

A recent study found that high K supply decreased concentrations of Ca and Mg in cannabis leaf tissue, indicating antagonistic relationships between these positively charged ions (Saloner et al., 2019

You're welcome. "Based on the results of this study, we recommend providing plants with a nutrient solution containing N and P at approximately 194 and 59 mg L–1, respectively, to achieve maximal inflorescence yield." Of course this was a DWC medium.

I've been trying to provide botanical reasons why growers need to get off the forum hype and cannabis foods for decades, but with every new crop of newbies.......

It's a vicious trap.

Bottom line? Give your plants a balanced NPK food with a complete micros package from start to finish and you'll support the production and maintenance of root and foliage tissue to produce the flowers you seek.

UB

 

[Dime]

A good fertilizer and a skilled grower will provide everything needed without need for additives.

 

[Ultramarin]

A good fertilizer and a skilled grower will provide everything needed without need for additives.

i would express a similar sentiment. since i only cultivate for personal use in soil, i abstain from using any elaborate additives. years ago, when managing larger commercial crops on rockwool with canna fertilizers to attain the sought-after 'dutch taste' desired by customers, i observed that only certain voracious hybrids, like k2 or powerplant, might have gleaned a marginal benefit from the standard application of pk13/14 in weeks 4-6. conversely, if you're unfamiliar with the precise requirements of your chosen clone, excessive or improper use of pk could easily diminish your harvest and compromise the overall quality of your crop. perhaps the biggest bullshit lies in the rather expensive boosters. i once received a complimentary 10L container of the "famous" yet exorbitantly priced 'canna boost.' i experimented in a room with 50 lamps, one side with the booster and the other without – no discernible difference, not in output and not even in "taste", which is the primary claim canna advertisement makes...

 

[Cerathule]

Tissue Analysis

The PK accumulation rate is fairly consistent, except for a steep climb through the 4th week of flower.
Some approach this by raising PK a little, over a slightly longer period.
Others increase PK a lot, for just a few days, starting week 3. The idea here, is if the week came early, you catch the tail end of it. Otherwise, you are getting it in there before it's needed. The plant can store them, and move them about when it needs to.
P&K are mobile, and are stored in leaves throughout veg, for use in bloom. This means your defoliation program has an influence on where the plant gets the PK from. If you have stripped the plant bare, it's more likely to respond to you giving it the PK, it can no longer get from the older foliage.

Most feeds are stacked with P, and so it doesn't need a boost. K has been shown as quite useless in many tests. Only really serving to control water movement. Though that ties directly to CO2 intake, so it can't be ignored.

Most balanced feeds have what is needed. Even an all-in-one garden food, if you let the plant/compost store the PK through veg, and don't then take all the stores away.
I don't see real gains from adding them, unless the plant actually asks. Which is rare. What I see more, is premature browning of the white hairs, which is tied to one of the two, but I can't be certain which. PK can fry a plant overnight, using bottle recommendations. P gives weed that chemical taste we find everywhere, and K can make sparks. They can be useful, but are really advanced gardening tools. One's I hope not to need. As the goal is to find a base feed that works, so you don't need lots of bottles.

My recent use of PK has been turning veg food to bloom food, and also correcting a whole range of new bases I was trying. Oddly, with all the tools, I ended up formulating what seemed to work best, then finding my usual Ionic was the closest base feed I could find to ideal. Or for me at least, as I just want a bottle of something. Not lots of bottles, to act like a mad scientist.

That diagram doesn't show a tissue analysis. It's the NPK feed schedule from Bill Farthing

 

[I Care]

When you guys are listing PPMs please specify which N P or K it is referring to. I lowered my N overall. PPMs just went in at about 40-30-50. I actually have to be somewhere for a change. Want to quiet some of you.

 

[Cerathule]

Plant roots can absorb an ammonical salt such as ammonium sulfate but not pure urea for example. FWIW, I use the hell outta ammonium sulfate in bulk, mainly for my turf, BUT, if I need a hit of N to back off some yellowing leaves in weed then I might drop a pinch in a gallon of rain water for my cannabis faves, soil culture.

Yeah plants can - and do - absorb urea passively with the mass flow, as well as they can actively compete for even much larger N-molecules, in the form of aminoacids.
But studies have shown Cannabis prefers nitrate, and it is suggested to not cross over 10% of NH4 to NO3.

BTW that diagram also shows nitrate.

 

[Cerathule]

In a nutshell, nutrient uptake is a function of osmotic pressure across the root gradient initiated by transpiration

Inside the plant root, the plant builds large ionic biomolecules which exert such a strong physioelectric force that the water flows osmotically from outside the root to the inside. Because there exists a physical law that makes water, which is dipolic molecule, ie. it has a negative and a positive electrically charged pole, being attracted to these ions, which are way too large to leave the roots. But the water can flow easily through the semipermeable plant membranes. So the water always tends to flow to, and thereby dillute, the presence of the greatest salt/ion concentration. This then generates a large pressure on the inside of the roots which is called "the osmotic root pressure" and this is one way how plants do "drink".
The other way is the transpirational pull, a negative pressure, caused from (mostly) the evapotranspiration from photosynthesis. Yes, you are right this can, in very high trees, create close to a vacuum in the vascular bundles.

 

[Cerathule]

Give the plants just what they need is a poor and sad line of thinking.

It's a damn naive way to think, to begin with, yes. Because, how do you know what it actually needs. Best is to absorb scientific studies, and if you're lucky you find the more indepth ones, with an array of tissue sample analysis, but even that is not failproof. The feed schedule can heavily influence the results. Though gradients can be shown, like Bugbee did. But it still leaves a huge question mark on what the plant gets inside a pot that is filled with soil, and there is PPFD, photoperiod, light spectrum, temperature, transpiration, VPD, genetics so many variables which can have generally an influence at the optimal feed EC or nutrient composition.

 

[Cerathule]

Haha, yeah its not necessery, but for example:

Silica - makes plant resistive to mould, experiments being done, thats a fact. Silica is never included in any nutrient as far as ive seen .

Fulvic/humic - helps in chelating microelements and uptake, especially in soil.

Mollases - feed micro organism = roots gets to its full potential, improved nutrient exchange (especially in organic growers, where nutrients are absorbed differently than mineral ones)

Root stimulators - have special hormones which signals plant to expand rootzone +essential elements for the momment roots doing its job.

Recently found a study, where Calcium uptake is stimulated by presence of specific amino acid chains in the medium.

Enzymes, which helps to brake down dead roots preventing from futher rot and invitation of parasites

Problem is one doesn't know in advance how the side- or interactive effects will be when using all this stuff alltogether, with no practical prior experience. It's a huge risk, introducing to a thoroughly general plant based feed like Peters etc. One would have to be a professional scholar to being able to anticipate this.

There was this guy, who thought of himself being a Dr. Ag, even though he stilled lived at his mom and couldn't even drive a car lol. But he read all these studies, oh, this will do this beneficially, oh, and this does that super.... so he bought himself like 30 or 40 bottles and powders and used everything according to the studies. Then after 3 weeks into flower all the plants looked stunted, and after 6 weeks in all the colas developed botrytis, so he could throw the work from 3 months all away lol.

Because the science, it doesn't show the whole picture. If anything, just begin by adding 1 new ingredient, and then judge the result and go from there. Also, calculate the investment return.

 

[cfl...KING]

I've run with an without canna boost, I will never grow without it again. I run 10ml per gallon up to 15ml per gallon. Never tried the minimum of 6ml per gallon.

With 10-15ml there is a very noticeable difference in the end product. Back to back grows with the same clones an same environment. All other nutes remaining the same.

As far as pk13/14 it's not going to make a low yield plant all of a sudden yield 3-4lbs per light. But being $25 for a liter that will last many grows, I will continue to run it. I do see how it could potentially decrease overall thc% because it's increasing plant material an the overall amount of THC will stay about the same.

 

[Old Uncle Ben]

Because the science, it doesn't show the whole picture. If anything, just begin by and go from there. Also, calculate the investment return.

Homey don't need no internet science. Been doing this far too long. My cannabis gardens from 1999 were as good as they are now. Why? Because I learned early on what makes a plant tick by growing all kinds of material like orchids, carnivorous plants, veggies, fruit trees, shrubs, shade trees, etc.

Folks here don't have that kind of knowledge base, instead they rely on forum logic and bro science.

"If it feels good, do it".

"....adding 1 new ingredient, and then judge the result" is just fishing.

I see no reference in this thread to what really matters - leaves and root tissue production. Just a bunch of shit about what's in a bottle and "how much do I add and when?"

UB

 

[Ultramarin]

Homey don't need no internet science. Been doing this far too long. My cannabis gardens from 1999 were as good as they are now. Why? Because I learned early on what makes a plant tick by growing all kinds of material like orchids, carnivorous plants, veggies, fruit trees, shrubs, shade trees, etc.

Folks here don't have that kind of knowledge base, instead they rely on forum logic and bro science.

"If it feels good, do it".

"....adding 1 new ingredient, and then judge the result" is just fishing.

I see no reference in this thread to what really matters - leaves and root tissue production. Just a bunch of shit about what's in a bottle and "how much do I add and when?"

UB

hemp is a weed.

turning its cultivation into a science is, outside of industrial large-scale production, pure time wastage or a dull hobby. i've dealt with ten different barrels long enough; if you somewhat know what you're doing and do it right, the differences are at best marginal or hallucinated..

 

[Tynehead Tom]

These conversations always kinda break down into a circle jerk of ideas and the science and or experiences that drive them.
What have I learned in 34 years with this plant..... there is no one method, no one nutrient mix or soil recipe that will cover all the bases for all cannabis plants. Some strains benefit from boosters , some do not and some give stress reactions when boosters are applied to early.
I think the bottom line is , a grower needs to understand and get to know the strains they grow and they will eventually learn (or not) the needs of the plant through it's life stages and be able to tailor feed schedules to satisfy those needs.

Myself, indoors, I stick to pretty much a modified Lucas formula and I do use both Liquid and powdered kool bloom when appropriate and for the strains I know show favorable responses when it is applied correctly.
Outdoor I use an organic mix and water only.

Right now I am on the beginning of my journey to grow with high brix methods of feeding the microbial life and not the plant per say.

 

[goingrey]

What kind of yield increases can one expect with PK boosters say on some Cookies hybrid? Are we talking single digit or double digit percentages?