Getting to the bottom of the Phosphorus question in flower

J

Jennygrows2

Member
I'm getting back into hydro and thought I would get a little more exact with specific NPK ratios rather than following one of the various nutrient schedules.

A common theme I see is a N:K ratio of 1:2. It's pretty consistent across recommendations and somewhat consistent in nutrient schedules.1-3-2 comes up often. I'm also seeing 1-2-2 and 1-1-2. Those all keep the same N:K ratios but P is all over the place.

Adding up the values in a common brand schedule at week 4 of bloom using the boosters comes out close to 1-3-3. Some people have suggested something closer to 1-4-4. I've also seen 1-2-3.

I'm not sure what to make of it, or where to start in testing different formulations. Anyone know why P recommendations are anywhere between 25 and 50% of the NPK content? That seems like a pretty major spread. I know there are a ton of NPK threads on the net, but it seems rare for anyone knowledgeable to come along and offer some insight on how much phosphorus is just right. More likely it's people saying what works for them, but I guess they all work to some degree.

I'm leaning towards a 1-2-2 formula mid flower

Veg: 4-2-3
Bloom week 1: 1-1-1
Bloom week 2: 1-1-1
Bloom week 3: 2-3-3
Bloom week 4-7: 1-2-2

I will have two areas so I can do an alt formula for comparison.
 
J

Jennygrows2

Member
I added up the NPK values for the Flora Nova line

Simple Program:
45.5-86.5-78.5

Expert Program:
55.5-91.5-113.5

Either way, close to 1-2-2
 
J

Jennygrows2

Member
Yodaweed said:
floranova works pretty good in soil, it's very concentrated so be careful not to use too much cause it can cause burns quickly.
Click to expand...
Thanks, I'm not going to use it. I'm just analyzing various brands to get at their week 4-5 bloom NPK ratios. What do you prefer (NPK ratios)?
 
J

Jennygrows2

Member
whitebb2727 said:
I prefer a balanced feed. Close to even NPK all the way through. I think bloom boosters are over rated and only certain strains will need higher amounts of K or P for that matter.
Click to expand...
What I've read indicates 1-1-1 is a good "basic" or "safe" ratio. Not knocking it. It does kind of indicate that ratios like 1-4-4 are either overkill or borderline nitrogen deficient, depending on how you look at it.
 
whitebb2727

whitebb2727

Well-Known Member
Jennygrows2 said:
What I've read indicates 1-1-1 is a good "basic" or "safe" ratio. Not knocking it. It does kind of indicate that ratios like 1-4-4 are either overkill or borderline nitrogen deficient, depending on how you look at it.
Click to expand...
It why you see so many yellowing plants at week 4 or 5. They are starved of N.

I've used dynagro foliage pro 9-3-6 from start to finish and it works great.
I like to try to keep them green to the end.
 
im4satori

im4satori

Well-Known Member
Jennygrows2 said:
I added up the NPK values for the Flora Nova line

Simple Program:
45.5-86.5-78.5

Expert Program:
55.5-91.5-113.5

Either way, close to 1-2-2
Click to expand...
@Jennygrows2

these numbers are incorrect, im not sure where you getting them

I understand what your trying to figure out and ask but the way your asking it doesn't really make sense to me

best I can figure your confusing 2 different fertilizer scenarios

first
theres mixing ratios, for example

if your your mixing a 3 part fertilizer you might mix it at ratios such as 1:2:3 which might indicate something like
30mls micro
60 mls grow
90 mls bloom

second
theres what your fertilizer solution yields after you factor in the mixing rates and water volume
for example

5 grams per gallon maxi bloom might yield something like (just an example not exact)

80 ppm N
80 ppm P
160 ppm K

which would be a 1:1:2 ratio of N:P:K


if I recall
flora nova bloom yields something around

90ppm N
80 ppm P
120 ppm K

at 7.5mls per gallon



as far as the perfect amount of P

phosphorus is one of those elements that plants can often times handle high levels but also do just fine with lower levels

often times the amount of P in any given fertilizer will depend on the dry fertilizer salts used to make them

for example

if you want to blend a fertilizer and you want to add more potassium

you could use

potassium sulfate( K-S)..... which will add potassium and sulfur
or
monopotassium phosphate (mpk)...which will add potassium and phosphorus
or
potassium nitrate...(K-N)which will add potassium and nitrogen
or
potassium silicate...(k-si)which isn't soluble with anything else in a concentrate so its largely prohibited base nutes

if the manufacturer chooses to get there potassium from K-S youll get a fertilizer with more sulfur, or maybe he uses mpk and you get more phosphorus

because most plants can handle substantially more sulfur and or phosphorus than whats required, therefore the manufacturer has the ability to alter his mix ratio based on what the bottle is derived from

typically for bloom youll find two basic ratios and some that exist in the middle

1:1:2 N: P; :K
2:1:3 N : P :K (which is what I prefer)


then theres the ratio for potassium, calcium and magnesium which ideally would look like this

3:2:1 K:Ca:Mg

for example I prefer something like

N 100
P 50
K 150
Ca 100
Mg 50

which is likely about EC 1.5
the amount of P can go down as low as 40ppm and up to as high as 80ppm and im fine with that..but anything more than 80ppm I feel is too much

the N:K ratio is more critical

hopefully that helps
 
J

Jennygrows2

Member
im4satori said:
@Jennygrows2

these numbers are incorrect, im not sure where you getting them

I understand what your trying to figure out and ask but the way your asking it doesn't really make sense to me

best I can figure your confusing 2 different fertilizer scenarios

first
theres mixing ratios, for example

if your your mixing a 3 part fertilizer you might mix it at ratios such as 1:2:3 which might indicate something like
30mls micro
60 mls grow
90 mls bloom

second
theres what your fertilizer solution yields after you factor in the mixing rates and water volume
for example

5 grams per gallon maxi bloom might yield something like (just an example not exact)

80 ppm N
80 ppm P
160 ppm K

which would be a 1:1:2 ratio of N:P:K


if I recall
flora nova bloom yields something around

90ppm N
80 ppm P
120 ppm K

at 7.5mls per gallon



as far as the perfect amount of P

phosphorus is one of those elements that plants can often times handle high levels but also do just fine with lower levels

often times the amount of P in any given fertilizer will depend on the dry fertilizer salts used to make them

for example

if you want to blend a fertilizer and you want to add more potassium

you could use

potassium sulfate( K-S)..... which will add potassium and sulfur
or
monopotassium phosphate (mpk)...which will add potassium and phosphorus
or
potassium nitrate...(K-N)which will add potassium and nitrogen
or
potassium silicate...(k-si)which isn't soluble with anything else in a concentrate so its largely prohibited base nutes

if the manufacturer chooses to get there potassium from K-S youll get a fertilizer with more sulfur, or maybe he uses mpk and you get more phosphorus

because most plants can handle substantially more sulfur and or phosphorus than whats required, therefore the manufacturer has the ability to alter his mix ratio based on what the bottle is derived from

typically for bloom youll find two basic ratios and some that exist in the middle

1:1:2 N: P; :K
2:1:3 N : P :K (which is what I prefer)


then theres the ratio for potassium, calcium and magnesium which ideally would look like this

3:2:1 K:Ca:Mg

for example I prefer something like

N 100
P 50
K 150
Ca 100
Mg 50

which is likely about EC 1.5
the amount of P can go down as low as 40ppm and up to as high as 80ppm and im fine with that..but anything more than 80ppm I feel is too much

the N:K ratio is more critical

hopefully that helps
Click to expand...
Thanks for the response! Sorry it took so long to respond I haven't logged in in a while.

First, to make sure there's no confusion, the numbers I posted are just ratios not percentages, and they are based on the full line of products listed in each companies nutrient schedule so working out the NPK ratio for the base nutrients (1, 2 or 3 part formula) would yield a somewhat different ratio. I used the full line because in theory since these companies want us to use all their products I assume it represents the best NPK they can formulate.

Looking at the FloraNova Bloom bottle it lists NPK as 4-8-7 so I'm not sure how you're coming up with 90-80-120. 4-8-7 even without the various additives in the feed chart comes out close to 1:2:2.

Looking at the Maxibloom packet NPK is listed as 5-15-14 so I'm not sure how you're getting 80-80-160 or 1:1:2 rather than 1:3:3 which is what the bag seems to indicate.

If I'm missing something I'm curious to know what it is.

On another note, I was corresponding with someone in another forum who mentioned 150 PPM of CalMag which is similar to your recommendation. If I remember correctly CalMag is generally mixed at a 3:1 ratio so it's slightly different but still close. I've been bumping my tap water up to 150ppm with CalMag prior to adding other nutrients.

Any additional comments would be appreciated. Regarding P I'm beginning to see it can work in a wide range, but without a specific reason there's no reason to use more than necessary. This supports your 1:1:2 and 2:1:3 preference. However unless I'm missing something it seems canna specific nutes do generally lean toward 1:2:2 mid bloom. Perhaps there are some strains that can use more P and they are just covering their bases?
 
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im4satori

im4satori

Well-Known Member
the reason nute companies separate into several bottles are for the following reasons

1) they want to increase there profits buy selling you more bottles
2) certain elements are insoluble when combined in a concentrate in most cases (for example sulfur and calcium)
3) silicate isn't soluble with anything in a concentrated form so its always separate
4) they separate a calmag product to accommodate source water differences... you may or may not have adequate calcium already provided by your source water depending on how hard your water is

in most cases theres no reason a 2 part fertilizer cant be adequate if properly blended by the manufacturer

im still not following all the ratios your siting

I still feel as thou your confused

ratios are use to describe different things, and it seems to me your confusing 2 separate things
for example
you might mix fuel for you weed wacker at a 5:1 ratio adding oil to the fuel for a 2cycle engine


your speaking about mixing ratios for a specific liquid fertilizer that has 3 parts for example

part A 30mls
part B 60 mls
part C 90 mls

and yes that's a 1:2:3 mixing ratio for that fertilizer

I apologize if im wrong and maybe im just stoned and not following

but it sounds to me like your confusing what I described above (mixing ratio)

with another example in which people describe a ratio

that ratio would be specific to the PPM of each element in a solution

for example using a nutrient calculator you can convert the % amounts on the bottle to identify exactly how much of a single element there is in the solution after its been mixed
for example
if I add

20mls per gallon part A
40 mls per gallon part B

the solution might contain

100 ppm nitrogen
100 ppm phosphorus
200 ppm potassium

this is a 1:1:2 ratio of active elements in the solution after its mixed....... not to be confused with a mixing ratio of a certain brand

or you might just be speaking about the three number on the bottle % amounts
as you sited the flora nova % amounts on the bottle but people dont generally speak of those numbers in terms of ratios

again
I apologize if im just not understanding your question, perhaps im incorrect about my assumption, but either way I don't understand

maybe you can be more specific about which brand and what the ratios % amounts are for that brand
 
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im4satori

im4satori

Well-Known Member
my nutrient calculator (which does the math for me) says;

if I mix 7.5ms floranova 4-8-7 (1 part) bloom per 1 gallon of 0ppm source water the resulting solution (if taken and tested by a lab) would have

79 ppm nitrogen
69 ppm phosphorus
115 ppm potassium




if you mix general hydroponics 3 part
per gallon
2 mls grow
4 mls micro
6mls bloom
1.5mls kool bloom

the resulting solution will/should test at a lab (+/-)

63ppm N
54 ppm P
121 ppm K

this would be a ratio of 1:1:2 nitrogen: phosphorus: potassium in the final mixed solution
 
im4satori

im4satori

Well-Known Member
the only way to truly compare a fertilizer is to convert the % numbers into active elemental ppm within a solution
based on how its dosed per gallon

looking at mixing ratios of a particular brand of fertilizer is basically just following a recipe but doesn't really tell you whats in it
 
J

Jennygrows2

Member
There is some miscommunication I think, but not mixing ratios as you are suggesting.

I understand that NPK listed on the bottles is molecular weight, but I've been assuming when talking about NPK ratios that molecular weight was being used.

Seems like it would be easier to have elemental percentages listed on the bottle, or to talk about NPK as molecular weight (which I seeing will vary based on what form is used).

You are using something like HydroBuddy?
 
J

Jennygrows2

Member
Taking another look at the Floranova,

.25% ammoniacal nitrogen * .34 is .085
3.75% nitrate nitrogen
Total is 3.835% nitrate nitrogen

8% P2O5 * .4364
Total is 3.49% phosphorus

7% K20 * .83
Total is 5.81% potassium

For a NPK ratio of 3.835:3.49:5.81, same as 79:69:115

Now it's making sense. I'm going to try and get acquainted with HydroBuddy though.
 
im4satori

im4satori

Well-Known Member
Jennygrows2 said:
Taking another look at the Floranova,

.25% ammoniacal nitrogen * .34 is .085
3.75% nitrate nitrogen
Total is 3.835% nitrate nitrogen

8% P2O5 * .4364
Total is 3.49% phosphorus

7% K20 * .83
Total is 5.81% potassium

For a NPK ratio of 3.835:3.49:5.81, same as 79:69:115

Now it's making sense. I'm going to try and get acquainted with HydroBuddy though.
Click to expand...
you've got some math there that I don't understand and cant speak too
perhaps its just above my math skills, but



Jennygrows2 said:
There is some miscommunication I think, but not mixing ratios as you are suggesting.

I understand that NPK listed on the bottles is molecular weight, but I've been assuming when talking about NPK ratios that molecular weight was being used.

Seems like it would be easier to have elemental percentages listed on the bottle, or to talk about NPK as molecular weight (which I seeing will vary based on what form is used).

You are using something like HydroBuddy?
Click to expand...
I agree, its very confusing the way the industry chooses to do it

im guessing its parlty because they really don't want you to know that its all the same... they want to try and "brand" it and the best way to do that is to fool you into thinking theres something special about there "brand"...when really its just all the same stuff but in different ratios

while that shit don't fly in the commercial ag industry because theyre likely edumicated lol

but the average home hobbiest can easily be fooled with all the wild claims and false advertising and pay big money for what actually cost pennies to make
 
im4satori

im4satori

Well-Known Member
these are the numbers that I prefer most for bloom

100ppm N
75 ppm P
150 ppm K
80 ppm Ca
50 ppm Mg

heres how I mix it

5 gallons finished concentrate = 640 gallons finished solution

mix at a rate of 1oz part A and 1 oz part B per gallon for a finished EC of 1.2 (+/-)

part A
1000 grams calcium nitrate
400 grams potassium nitrate
400 grams magnesium nitrate
64 grams iron dtpa

part B
800 grams monopotassium phosphate
1000 grams magnesium sulfate (aka Epsom salt)
5 grams solubor (boron)
7 grams Manganese sulfate
0.3 grams molybdenum
1 gram zinc
0.5 grams copper

fill two 5 gallon bucket half way with hot water

label each bucket either A or B

add fertilizer salts at weights above in corresponding buckets and stir until dissolved

then top off until buckets are full with equal portions water in each bucket


I buy it all here
https://customhydronutrients.com/
 
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J

Jennygrows2

Member
im4satori said:
you've got some math there that I don't understand and cant speak too
perhaps its just above my math skills, but
Click to expand...
I'm sure not above your skills, just need to understand the multipliers. Ammoniacal nitrogen breaks down to 34% nitrate nitrogen. P2O5 is 44% phosphorus and K2O is 83% potassium.

im4satori said:
while that shit don't fly in the commercial ag industry because theyre likely edumicated lol
Click to expand...
Well, not going to contest that there's a lot of snake oil out there but after doing some looking around it seems the entire fertilizer industry uses molecular weight.

Anyway, thanks for the correspondence. If you hadn't posted I would have continued to be in the dark for who knows how long. I'm going to start by using a calculator with pre mixed ferts. Maybe at some point I'll start mixing my own :)
 
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