When do you start adding your PK?

[DanTheReggaeFan]

I'm just wondering when everyone starts adding their PK booster in flower. I use Shogun Coco nutrients (UK company I think) and their feed chart shows to start using it in week 3 of flower but the bottle itself says "Use from the fourth week in the flowering cycle or when the vegetative growth has stopped during the flowering cycle."
To me that's 3 different times, because I've got plants that are only 2 weeks from the flip and are starting to put out pistils.

So which is it? What does everyone else do, 3rd week, 4th week or when pistils appear? Or maybe even something else?

 

[troutman]

Regardless, what nutrient you use just increase slowly and you'll have less issues.

 

[flylowgethigh]

It says after stretch is over, about 3-4 weeks from flip. A little agsil-16 helps build good stems so the stretched plant can support all those massive colas.

 

[Ca++]

I don't think I believe in PK. It's difficult to say out loud, as like Santa, you want it to be true. Real life examples don't support it though. The timing often given seems suited to K, but too late for P. Which is already abundant in most feeds anyway. Many PK boosts are balanced similar to the feeds they pair with. So you would probably be better to just use more feed. So you also get more N and Mg, so you can grow more green.

Some PK boosts have much more K than P, which makes more sense.

Regarding P, I feel elevated levels have use in the first week or two. Serving to increase frame mass.


I can't see any logic, or papers, to support PK boosters. They actually move away from university polished feeds. Though we could devise a feed that needs PK, in order to make you buy it.

 

[Terppalooza]

I don't think I believe in PK. It's difficult to say out loud, as like Santa, you want it to be true. Real life examples don't support it though. The timing often given seems suited to K, but too late for P. Which is already abundant in most feeds anyway. Many PK boosts are balanced similar to the feeds they pair with. So you would probably be better to just use more feed. So you also get more N and Mg, so you can grow more green.

Some PK boosts have much more K than P, which makes more sense.

Regarding P, I feel elevated levels have use in the first week or two. Serving to increase frame mass.


I can't see any logic, or papers, to support PK boosters. They actually move away from university polished feeds. Though we could devise a feed that needs PK, in order to make you buy it.

I agree with this. I'd like to see if more p is actually good for the plants early in flower or not tho. I feel, the calixes swell a bit faster with more p. But also maybe hairs stop building up fast. The bud just want to fnish faster this way maybe

 

[Ca++]

I agree with this. I'd like to see if more p is actually good for the plants early in flower or not tho. I feel, the calixes swell a bit faster with more p. But also maybe hairs stop building up fast. The bud just want to fnish faster this way maybe

I'm glad you said that. I have noticed an finish early with high P. I can't say for sure it's the P, but I have been studying it. Half my plants will get to about 4 weeks, but not really link up by 4.5 weeks. Each bud will stay separate. Also, low on hairs, and what there is brown early. The individual nugs look done by 6 weeks. Having moved towards finishing, not linking and fattening.
I only saw this in half, but lower P has lengthened the flowering of all the plants. So I think while some were halted at stacking, they were all effected. Things rated 7-8 weeks that really like 8-9, were actually done at 7. Another 47 day plant was by the book with higher P, but lower (40-50) has it still going past 8. These are not minor changes, to plants I know well. Unfortunately this lower P run is at a new property, which has had it's own impact beyond the norm. So I may have to run up&down the numbers again, before I can be sure. Which I'm unlikely to do, having run low P traditionally, and back on low P, they look like they traditionally have. My dive towards 100ppm P wasn't good. I think it's the 10 lights thread, where I post up professional graphs of the P accumulation I also encountered. By week 3, the plants were rejecting 100P so much, I had runoff of about 200P (concentrated as the plants took the water and left the P). I would have to check my papers to get the number. It was about 200. However the bigger professional study covers more concentrations.

I think the rapid expansion of the plant gives us the chance to stash some of this luxury P. Not just stash, but use, as the frame really improves. Forget the idea it reduces stretching though, this improvement is Major Oak stuff. Then as the stretch grids to a halt, the P use does. It's hand in hand, day by day. It makes no sense to me, to wait another week or two, then add PK. It just seems to burn the hairs. Some little buds up the stalk, way below, out the light... sometimes dry overnight after a PK hit. Witnessed by a few friends, before we chatted about it. Like they crystalised or something. Peculiar and worrying.

As soon as flower is set in, it's tissue samples and weigh-in's confirming 30P should do. A bit more can be stored. As the P accumulation drops, it's a handover to K. So right around 18 days, you are likely to of stopped boosting P, and started on K. The K timing can steer the plant along towards using it, rather than being late with it, and missing an opportunity.
Keeping them both present is excess salts, and excessive EC looses yield.


I just can't justify PK. From the days I knew it burnt them, until today when I know a little bit more. I just can't see it...
There was once an article about why they come together. At the time I didn't care. Looking back, it might of been less about the plants, and more about chemistry.

 

[Hammerhead]

Never I don't use it. If you must just add Silica

 

[Terppalooza]

I'm glad you said that. I have noticed an finish early with high P. I can't say for sure it's the P, but I have been studying it. Half my plants will get to about 4 weeks, but not really link up by 4.5 weeks. Each bud will stay separate. Also, low on hairs, and what there is brown early. The individual nugs look done by 6 weeks. Having moved towards finishing, not linking and fattening.
I only saw this in half, but lower P has lengthened the flowering of all the plants. So I think while some were halted at stacking, they were all effected. Things rated 7-8 weeks that really like 8-9, were actually done at 7. Another 47 day plant was by the book with higher P, but lower (40-50) has it still going past 8. These are not minor changes, to plants I know well. Unfortunately this lower P run is at a new property, which has had it's own impact beyond the norm. So I may have to run up&down the numbers again, before I can be sure. Which I'm unlikely to do, having run low P traditionally, and back on low P, they look like they traditionally have. My dive towards 100ppm P wasn't good. I think it's the 10 lights thread, where I post up professional graphs of the P accumulation I also encountered. By week 3, the plants were rejecting 100P so much, I had runoff of about 200P (concentrated as the plants took the water and left the P). I would have to check my papers to get the number. It was about 200. However the bigger professional study covers more concentrations.

I think the rapid expansion of the plant gives us the chance to stash some of this luxury P. Not just stash, but use, as the frame really improves. Forget the idea it reduces stretching though, this improvement is Major Oak stuff. Then as the stretch grids to a halt, the P use does. It's hand in hand, day by day. It makes no sense to me, to wait another week or two, then add PK. It just seems to burn the hairs. Some little buds up the stalk, way below, out the light... sometimes dry overnight after a PK hit. Witnessed by a few friends, before we chatted about it. Like they crystalised or something. Peculiar and worrying.

As soon as flower is set in, it's tissue samples and weigh-in's confirming 30P should do. A bit more can be stored. As the P accumulation drops, it's a handover to K. So right around 18 days, you are likely to of stopped boosting P, and started on K. The K timing can steer the plant along towards using it, rather than being late with it, and missing an opportunity.
Keeping them both present is excess salts, and excessive EC looses yield.


I just can't justify PK. From the days I knew it burnt them, until today when I know a little bit more. I just can't see it...
There was once an article about why they come together. At the time I didn't care. Looking back, it might of been less about the plants, and more about chemistry.

hmm so you find ifyou give more p early. they will finish faster and stack less? yes? that would support my observations. i should really make a side by side test next run

 

[Terppalooza]

also i recently stopped pkaing my plants. im not shure how satisfied i am. i think it really doesnt make that much of a difference if you feed them right in the first place. some of my organic runs where they are heavily depleting p and k towards flower week 4-6 thats when i start feeding pk for thoese. but be carefull most the pk formulas are way out of logical range xD like c++ may just make your weed worse XD

 

[Hiddenjems]

Using nothing but general hydroponics micro and bloom in the same ratio but increasing concentration until week 6 I get perfect results for around $10 in nute cost per lb of flower.

If you want to manipulate npk just vary the ratio of your multi part feed. Buying extra bottles of the same chemicals in your base feed is just wasting money.

I’ve tried mono potassium phosphate in various quantities at different times and noticed maybe a 5% increase in yield at best.


In my experience you’ll get 90% of all you can with great environment and base nutes dialed in. You’ll spend 5x as much money chasing that last 10% as you did on the first 90%, and probably end up worse off.

 

[DanTheReggaeFan]

Damn I really wish I'd asked this question before I bought the bottle lol

 

[Ca++]

hmm so you find ifyou give more p early. they will finish faster and stack less? yes? that would support my observations. i should really make a side by side test next run

I believe the 30ppm idea being spoke of, is enough. Though some substrates can interfere with availability, and some luxury P isn't necessarily bad. I have not actually been down to 30ppm, though have been close. It's difficult to achieve with the bottles most of us have to hand. I have done zero P short term, but at a time when it was very high in the runoff, so doesn't count. That was coco, following earlier 100P use. It just seemed to keep coming, like the P well of life.

My current mind set, is that anything up to 100P is alright, for about 7 days. They seem to take that (or the coco did). Jack's only switch to bloom for week one, then back to grow. Which is a little confirmation from someone that does a lot of work with feeds. For me, stretch is done about day 18, and so higher P use. The 30ppm probably works from here in.
Many have the goal of just one feed, for all of flower. Ramping the numbers up and down, but just one feed ratio. Bugbee's is out there to be read, and is simply a recipe without any further changes. I have run like that myself, but do feel some ramping up&down is needed. Not just with PK though. These are not flowers in that sense. We need N to grow plant matter, not petals. I think PK has been round for so long, that it's more guess work than researched. The idea P or K is needed at high levels, isn't being found in their studies. While the N people have held back on, is actually great for bulking buds, and not so involved in stretch as once thought.

Everything we used to know, we seem to of changed our minds about. One thing remaining, is that this plant is good at foraging. If it's there, and available, it will find it. Making crop steering with food, a difficult prospect.

 

[WingzHauser]

Guano at flip, potassium depends on if it's sulfate or carbonic. Potassium acetate is very available while ksul is not. Excess P seems to be a reason lots of weed sucks. Pk boosters only make sense for early bloom. If you're adding phosphorus you better add K also with Cannabis, a product like Phosgard in hydro.

Phos in late flower will have you "curing" your bud waiting for the weird burnt coco flavor to return to lemon skunk. General consensus seems to be get your plants to bloom before stems turn purple then abandon phosphorus for any risk of having unmetabolized P in the end product.

 

[Brother Nature]

I found in coco, feeding 1/2 dose for a week at the point when buds start, usually 3 weeks flower, then the same for a week at 5 weeks produced best results. But, like a lot of the other guys say, I didn't find it that beneficial, I found using the boost product and the basic a and b nutes produced much better results. This was with canna coco products. Might as well use it since you have it.

 

[GMT]

I'm in soil and have read that P will bind to other stuff almost immediately, making it unavailable to the plant. Therefore the only P available is during the feeding process. For that reason mainly, this round I have hesi P. A stand alone for the first few weeks of flowering to add to flowering nutes.
I'm just trying it on a merry go round clone for the first time (pics in thread). The pistils, normally all white at this point, have 25-30% brown hairs. I didn't know why until I saw this thread.
First try, so I can't comment on taste or harvest time yet, but I guess less P next time.

 

[Ca++]

I found in coco, feeding 1/2 dose for a week at the point when buds start, usually 3 weeks flower, then the same for a week at 5 weeks produced best results. But, like a lot of the other guys say, I didn't find it that beneficial, I found using the boost product and the basic a and b nutes produced much better results. This was with canna coco products. Might as well use it since you have it.

Many won't realise, but canna coco keeps the same feed for grow and bloom. It's for EC 0.4 water, and part of the feed profile change, is reducing N and increasing P going into flower, by changing from Nitric to Phosphoric acid. The feed is a little high in P for grow, as they expect it to accumulate.

Perhaps the first low feed week you did, was clearing away some of that excess P. Though they don't put lots in anyway.

 

[Tomatoesonly]

Never I don't use it. If you must just add Silica

What's your Si timing schedule? I remember talk or reading about Si in flowers might not be the best thing for a product that is burnt and inhaled???!!!

 

[Hammerhead]

Silica is used to help the plant uptake nutrients it's not a booster. The amount we use will never cause issues from smoked products. Bloom booster sure will. I'm still alive after smoking kilos of the weed produced in the 70s lol. No need to become paranoid about such things.

 

[Ca++]

Bugbee uses rice hulls in most mixes for silicone. He see's no nutritional value to them, but finds them a good preventative treatment against....

I think I fell to sleep. Mold perhaps. Don't quote me on that though.

 

[Brother Nature]

Many won't realise, but canna coco keeps the same feed for grow and bloom. It's for EC 0.4 water, and part of the feed profile change, is reducing N and increasing P going into flower, by changing from Nitric to Phosphoric acid. The feed is a little high in P for grow, as they expect it to accumulate.

Perhaps the first low feed week you did, was clearing away some of that excess P. Though they don't put lots in anyway.

Thought I'd offer the OP some advice as I ended up using the PK as it was given to me and I thought I'd give it a shot, but my situation was a bit more unique. I ran blumats, so it was a constant feed. Kept the nutrient EC at 1.2 the entire run, but the addition of the 1/2 strength PK, only bumped up to 1.4ec for the weeks it was used. Not overkill by any account, but I found that to be the sweet spot with blumats.

I really liked the Canna coco a & b, not having to swap ferts at flower was a good money saver, but I did have to use their cal-mag product to get my res to .4ec as my water was filtered rain water so contained nothing, much like RO. I also found when the local shop ran out of the Canna cal-mag, nothing else really worked with the A & B and the plants didn't respond well. I'd heard, on this site, in the coco section, very similar to what you hypothesize in the above quote so tried to follow it. The Cook's guide to CEC is still one of the best resources for coco growers looking to understand their medium. Anyways, I digress, hope the OP gathers some good info from this thread..