The Best N-P-K

[churchhaze]

I just finished reading this thread and agree with the general consensus. The only thing I disagree with is that a plant doesn't need much K for veg. Most tissue samples of fully expanded leaves will show that leaves pull up as much K as N, but require a very low level of phosphate for healthy growth. The Hoagland solution has an NPK ratio of approximately 3-1-4 and is meant to be a general all purpose hydroponic formula.

When I use a veg formula slightly higher in K than N, stems, petioles, and leaf veins tend to be much thicker and the leaves grow larger.

One thing to keep in mind about Ionic Grow's 3-1-5 formula is that it doesn't contain any iron, which by itself makes judging it against other formulas inconclusive.

I personally think that lucas formula is too low in potassium and too high in calcium because all the nitrates are provided as calcium nitrate instead of some also being provided by potassium nitrate from the "grow" bottle, then K deficiency is often misdiagnosed as Mg deficiency and Mg is applied, often in the form of calmag, which just makes the K:Ca even more distorted. An agriculture document I read recently was suggesting 4K:2Ca:1Mg ratio as a rule of thumb to keep cations from antagonizing each other.

All that said, I agree with all the advice. Give the plant what it needs, when it needs it and don't let all the leaves fall off before harvest time.

 

[moghazy]

Hello guys, So i'm about to plant my first Cannabis plant. I've been out for Nutrients and i finally found someone selling N-P-K.. I have got a super feed package of 20-20-20 that i got for Vegetating, and a starter pack 10-50-10. I want some guidance how much to put for my plant during both stages. I've been aiming to buy 20-5-5 and 5-15-15 but i couldn't find anything near and the seller said i should go back later for something to mix with 10-50-10 to give me 3-16-3 but that's out of stock and pff i'm frustrated i've been reading a'lot about planting weed and i'm fine with everything and about to go for buying soil components but i just don't get it with all the food thing (! I don't know how much to put per liter and will the 10-50-10 somehow do for flowering or i need to look for something else to mix or.. or.. or.. I'm melting downnn



All I'm thinking of is adding both 20-20-20 + 10-50-10 = 30-70-30 / 4 = 7.5 - 17.5 - 7.5 would that be fine for flowering ? or should i break it more ?

Would really appreciate the dosage.. in tsp / Liter. Idk if i should consider cannabis a fruit or a vegetable or..

Gonna be using soil [Compost + Peatmoss + Vermiculite]

 

[Dboi87]

Yep, what I've been saying for years, and you'll only find such wacked NPK values with such stuff as cannabis specific foods, the "lucas formula", etc. Think of cannabis as a flowering foliage plant. For some screwie reason, guys like GH always include more K than N, even in their "grow" foods. It's a plant nutrition farce. As a rule of thumb, use a high N food like a 9-3-6 to promote foliage, a 10-30-20 food to promote flowering, UNTIL, you begin to see premature yellowing of the lower fan leaves or overall plant which will result in necrosis if not corrected. Forget bud production and concentrate on leaf health and maintenance. Think outside of the box.

A 10-10-10 is a safe bet for an all-around NPK value.

UB

you say "UNTIL" premature yellowing. at that point what do i do? stop feeding or go back to the 9-3-6

 

[Uncle Ben]

you say "UNTIL" premature yellowing. at that point what do i do? stop feeding or go back to the 9-3-6

Yes, or any high N food or pure N food to correct it.

 

[Dboi87]

Thanks UB. So then what's the deal with flushing? Is it another myth?

 

[Dboi87]

I ask cause if I keep the leaves green til harvest then that would mean they've been fed all the way through. Is tastes really ruined when you don't flush?

 

[Uncle Ben]

"Flush" and don't flush then compare.

Again, it's damn hard for some of you guys to shake off forum paradigms and myths. You'll just have to find out for yourself.

 

[Dboi87]

That's why I ask you. I trust your word most on this site and as a complete novice in any horticultural/botanical sense its a little difficult to distinguish the real deal from the hocus pocus (even some that should be obvious like lollipoping).

Also I'm more so looking for the "why" rather than just a "do this" that way i'll have a better understanding and can eventually stop annoying you with my "noob" questions.

I wonder where all these myths even originated and how they became so prevalent.

Thanks for the help/info

 

[Dboi87]

P.s.
At this point I have no hard set beliefs or paradigms as you called them because its all so foreign. What I'm trying to do is learn the right way so I never gave to unlearn b.s. and when people only know one thing it's hard to even tell its subpar. I remember a cousin of mine went the first 13 years of his life thinking he saw the world as it should be like everyone else.turns out he was blind as a bat and couldn't believe the definition and detail he had been missing all his life.

Don't let me life my life blind as a bat UB!

 

[Dboi87]

By the way still reading mel franks book. I can already see plenty things in the book that completely go against popular cannabis cultivation culture/practices. I appreciate the referral. Good read

 

[acgreenski]

Hey Ben, thanks for all your posts! I'm wondering how much Ca I should use and what the danger level for toxicity is? I've heard it can lead to Mg and K deficiencies. Currently I'm trying to correct multiple deficiencies showing low N, Mg and maybe others in a soilless coco based mix. Mix is 50% quickroots, 50% perlite from groworganic.com. Mix comes out to 900ppm in the runoff on a 700 scale, but my seeds starts love it. Fed the NPK below at 585ppm after a flush down to 250ppm. Ph is at 5.8 but rises to 6.8 in the runoff. I use Cutting Edge 3 part, plus Botanicare cal/mag for the coco mix, but am about to cut out the grow after seeing this thread. I am drain to waste. I am in veg.
My NPK was:
N- 7
P- 4
K- 8.5
Ca- 11.4
Mg- 3.2
S- 2

I want to change this to a more balanced NPK after reading this thread and other posts. But first a 400ppm solution to bring up the Nitrogen like:
N---20.5
P---6.25
K---6.5
Ca--18.4
Mg--2.2
S-- 2

Then feed NPK at:
N---11.5
P---6.25
K---6.5
Ca--10.7
Mg--2.2
S---2

What do you think of my plan? Thanks!

 

[Uncle Ben]

Sounds good to me. Where did you come up with the NPK values, from the labels?

 

[acgreenski]

Cool, these values were determined by the labels and how much i use of each in a solution. Do you see any problems with 900ppm runoff with 6.8ph? Or the high calcium, which is in my micro? I'm also wondering if i should just add Nitrogen by itself to bump things up?

 

[Uncle Ben]

I don't do ppm's so I best not comment. Read your plants. They'll tell you what's going on.

I'd try door #3.

 

[acgreenski]

I see curling, yellowing, brown spots, striping with greener centers, canoeing, clawing down, yellow edges with green throughout the middle. I fed with the high nitrogen solution and then a N foliar @220 ppm and they do look slightly better, some of them are pointing up again. I switched to soilless to reduce chances of having to fight root aphids, but I never had so many deficiency/toxicity problems before. Maybe i should feed again with tea to get the herd working? I also have nice green plants in the same medium, the growth seems extremely slow but there are no visible signs of problems. So do you work with PH?

 

[Uncle Ben]

Let's start with your choices of plant food cause. That's where you start. Need specifics, not label names. Focus on how the new growth looks. Damage has been done on the old and will not recover. IOW, don't drive using your rear view mirror.

 

[thecoolman]

I

want to change this to a more balanced NPK after reading this thread and other posts. But first a 400ppm solution to bring up the Nitrogen like:
N---20.5
P---6.25
K---6.5
Ca--18.4
Mg--2.2
S-- 2

In my opinion way to little magnesium in this Fertilizer the calcium to mag ratio is off. The n to k ratio is off as well. I liked your original one better.
Ben is correct you have to read your plants. We need pics. If your going by ppm what is your ppm of your water before
adding fertilizer? Your using Cutting edge solutions..probably need all 50 of there bottles LOL..get a complete fertilizer! I run close to the same ppm but with only 20 percent coco 80 perlite.. very healthy with the jacks hydro formula. around 600 -700ppm on 500 scale or 840-980 on 700 scale cost about 100 dollars for around 4000 gallons mixed. You probably would run a little less ppm since you use more coco which has a high cation exchange.
Also no iron listed in yours?

 

[acgreenski]

Hey Guys, been really busy working 12 hour days. So the big problem was that I was on the 700 scale for ppms and I had no idea there was more than one scale. I was underfeeding like crazy and killing everything right off the bat. Before I had a pen which was on the 500 scale. Thanks for the help!

 

[churchhaze]

For hydroponic nutrients, there are 4 ways to add nitrates:

- potassium nitrate
- calcium nitrate
- ammonium nitrate
- nitric acid.

You want to keep ammonium low in hydroponics (it antagonizes K) so ammonium nitrate is not really an option. Nitric acid will clearly lower pH if you use it as a source of N, so that's not an option either unless the pH is too high.

This leaves you with calcium nitrate and potassium nitrate. You can't bump up nitrogen in a hydro mix without also bumping up either calcium or potassium or changing the pH.

That being said, your percentages show more calcium than potassium. Potassium should be about twice as abundant as calcium.

Or the high calcium, which is in my micro? I'm also wondering if i should just add Nitrogen by itself to bump things up?

 

[Uncle Ben]

For hydroponic nutrients, there are 4 ways to add nitrates:

- potassium nitrate
- calcium nitrate
- ammonium nitrate
- nitric acid.

You want to keep ammonium low in hydroponics (it antagonizes K) so ammonium nitrate is not really an option. Nitric acid will clearly lower pH if you use it as a source of N, so that's not an option either unless the pH is too high.

This leaves you with calcium nitrate and potassium nitrate. You can't bump up nitrogen in a hydro mix without also bumping up either calcium or potassium or changing the pH.

That being said, your percentages show more calcium than potassium. Potassium should be about twice as abundant as calcium.

Great info. Most if not all hydro growers end up with a N deficiency. DG Foliage Pro is 2.9% ammonical and 6.1% nitrate. Even though they tout it for soil too this food is designed primarily for hydro and soil-less mediums. N is derived from the nitrates of ammonium, calcium and potassium.

UB