Methodical, scientific approach to nutrients and nutrient formulations discussion

hi all, in this thread we will be discussing the npk and how it effects plant growth if you make your own ferts or add various things and tweak em a bit.
if this thread does take off like we are hoping I'd like to see it stickied

I love the title! Betcha it won't get as much attention as if you had posted "Humboldt, the secret to success!" ...or the Bushmaster thingie. Notice how quiet it got when I revealed the truth about this product and the risks involved? Hah!

https://www.rollitup.org/advanced-marijuana-cultivation/292518-bushmaster-how-guide-5.html

You could sit here and spends hours trying to consolidate, collect the thousands of posts regarding nutrition, errrrr, I mean vendor fertilizer and supplement products. Anyhow, here's a few links folks should memorize if they want to grow fine plants.

What is plant nutrition?
http://retirees.uwaterloo.ca/~jerry/orchids/nutri.html

Nutrient excesses and deficiencies
http://www.ces.ncsu.edu/depts/hort/consumer/quickref/fertilizer/nutri_def.html

The concept of nutrient antagonism
http://www.totalgro.com/concepts.htm

I can hear it now - "but is isn't pot!"

Well...... then go buy your snake oils, follow your charts, and rots of ruck.

Uncle Ben

Fathers of Hydroponic Nutrient Formulations

The last formulation Hoaglands is from 1950. As you can see the science has been around a while. That is why there is not much new, just a lot of new marketing.

(Jensen)
gm/100 gallons of water
magnesium sulfate 187
monopotassium phosphate 105
potassium nitrate 77 .
calcium nitrate 189
chelated iron {FeDTPA) 9.6
boric acid 1.0
manganese choride 0.9
cupric chloride 0.05
molybdic acid 0.02
zinc sulfate 0.15 ·

N, P, K, Ca, Mg, S, Fe, B, Mn, Zn, Cu, Mo
ppm 106, 62, 156, 93, 48, 64, 3.8, 0.46, 0.81, 0.09, 0.05, 0.03


(Cooper)
gm/100 gallons of water
potassium nitrate 221
magnesium sulfate 194
calcium nitrate 380
monopotassium phosphate 99
Iron chelate (FeEDTA) 30
manganese sulfate 2.3
boric acid 0.6
copper sulfate 0.15
zinc sulfate 0.17
ammonium molybdate 0.I4

N, P, K, Ca, Mg, S, Fe, B, Mn, Zn, Cu, Mo
ppm 236, 60, 300, 185, 50, 68, 12, 0.3, 2.0, 0.1, 0.02


(Johnson)
gm/100 gallons of water
potassium nitrate 95
monopotassium phosphate 54
magnesium sulfate 95
calcium nitrate 173
chelated iron (FeDTPA) 9
boric acid 0.5
manganese sulfate 0.3
zinc sulfate 0.04
copper sulfate 0.01
molybdic acid 0.007

N, P, K, Ca, Mg, S, Fe, B, Mn, Zn, Cu, Mo
ppm 105, 33, 138, 85, 25, 33, 2.3 , 0.23, 0.26, 0.024, 0.01, 0.007


(Larsen )
gm/100 gallons of water
potassium nitrate 67
calcium nitrate 360
potassium magnesium sulfate 167
potassium sulfate 130
chelated iron (FeDTPA) 12
phosphoric acid (75%) (40 ml)
Manganese sulfate 0.5
boric acid 2.2
zinc sulfate 0.5
copper sulfate 0.5
molybdic acid 0.04

N, P, K, Ca, Mg, S, Fe, B, Mn, Zn, Cu, Mo
ppm 172, 41, 300, 180, 48, 158, 3, 1.0, 1.3, 0.3, 0.3, 0.07

This is made essentially according to the following reference: D.R. Hoagland and D.I. Arnon. The water-culture method of growing plants without soil. Calif. Agr. Expt. Sta. Circ. 347. 1950. There is one change and that is in the form of iron added.
In making nutrient solutions, always add the required quantities of stock solutions to a fairly large volume of water and then make to volume. Stocks can be stored on the shelf. Below are the quantities to make Full Strength Hoagland's solution. In order to make ½ strength as used in most of this workshop just cut all stock solution amounts by ½ and make up to volume as usual.
Prepare the following stock solutions (1-6) and use the amounts indicated to prepare 1 liter ( final volume ) of nutrient solution:
1. 1.00 M NH4H2PO4 use 1 mL/L of nutrient solution
2. 1.00 M KNO3 use 6 mL/L of nutrient solution
3. 1.00 M Ca(NO3 )2 use 4 mL/L of nutrient solution
4. 1.00 M MgSO4 use 2 mL/L of nutrient solution
Micronutrient stocks: combine the following amount of salts in a total volume of one liter of water, and then use 1 mL/L of this entire stock mixture (5) along with the stocks above(1-4) and the iron stock (6) described below to make up a total of 1 L of nutrient solution.
5. 2.86 gm H3BO3
1.81 gm MnCl2 .4H2O
0.22 gm ZnSO4 .7H2 O
0.08 gm CuSO4 . 5H2O
0.02 gm H2MoO4 . H2O
(Asssaying 85% MoO3)
6. Iron stock: to the above 5 stocks add 0.25 ml of this iron stock for 1 liter of nutrient solution.
To make up the iron stock, take 26.1 g EDTA and dissolve in 286 ml water that has ~19 g KOH . Then dissolve 24.9 g FeSO4.7H2O in ~ 500 ml water. Slowly add the iron sulfate solution to the potassium EDTA solution and aerate this solution overnight with stirring. The pH rises to about 7.1 and the solution is wine red and very little precipitation occurs. Make to 1 liter final volume and store in a bottle covered with foil (dark).
Note: Hoagland’s recipe called for 1 ml of 0.5% iron tartrate stock per liter of nutrient solution but we use the above substitution.

The following chart is the basis for simple mixing of a nutrient formulation when you know the ppm concentrations you wish to have for a finished mix.

It does require some data not given such as conversions from liters to gallons. Also it does not address two part mixing to prevent precipitation. I will address those matters in another post. Where you see the **’s before a fertilizer it is because the previous listed compound contains more than one fertilizer. Example Calcium nitrate contains both nitrogen and calcium.

Chemical compound****Supplied element*****Grams for 1 ppm per 1,000 liters
Ammonium sulfate (21-0-0) Nitrogen 4.76
Calcium nitrate (15.5-0-0) Nitrogen 6.45
**********************Calcium 4.70
Potassium nitrate (13.75-0-36.9) Nitrogen 7.30
*************************Potassium 2.60
Sodium nitrate (15.5-0-0) Nitrogen 6.45
Urea (46-0-0) Nitrogen 2.17
Monopotassium phosphate (0-22.5-28 ) Potassium 3.53
*******************************Phosphorus 4.45
Potassium sulfate (0-0-43.3) Potassium 2.50
Potassium chloride (0-0-49.8 ) Potassium 2.05
Monocalcium phosphate
(triple super) (0-20.8-0) Calcium 13
*********************Phosphorus 4.78
Monoammonium phosphate (ll-20.8-0) Phosphorus 4.78
Calcium sulfate (gypsum) Calcium 4.80
Boric Acid Boron 5.64
Copper sulfate Copper 3.91
Ferrous sulfate Iron 5.54
Chelated iron 9% Iron 11.10
Manganese sulfate Manganese 4.05
Magnesium sulfate (Epsom salts) Magnesium 10.75
Molybdenum trioxide Mo03 Molybdenum 1.50
Sodium molybdate Molybdenum 2.56
Zinc sulfate Zinc 4.42
Pottasium Nitrate 2.6 grams KNO3 in 1000 ml of water equals 1 ppm K and 0.36 ppm N

The above formulas are just for educational and historical reference. They are not specifically designed for marijuana specifically but for general green house hydroponics. I have dozens and dozens of actual formulations that are more recent and of more interest to forum viewers. With them I will supply the guarnteed analysis, ppm of each salt or mineral etc., mixing amounts and directions for mainly two part mixes. I will also supply the calculated EC, pH and calculated final mixed TDS etc, etc. Typically I formulate for 100X concentrations in 1 gallon formulations. ie a generic equivalent to something like GH Flora Micro and Florabloom as the Lucas method would be a combined formulation made in a two part mix. That would mean two gallons so diluted it would be at a minimum of 200 gallons. However I formulate according to reported analysis so the strength is much greater than that bottled by someone like GH.

Generic Two Part ratio 1:2 ie Generic Lucas (Yes the same ingrediants could be mixed differently so that all the trace elements would be in part A like in Floramicro (part A) but then it would be a possible excuse for GH to base a complaint with the site administrators, so....)


Individual ppm's
Nitrogen 167
Phosphorus 333
Potassium 397
Magnesium 100
Calcium 215
Sulfur 133
Iron 3.33
Manganese 1.67
Boron 1.67
Zinc 1.00
Copper .33
Molybdenum .03

Ounces

Part A
Calcium Nitrate 28.5
Iron Chelate .90

Part B
MonoPotassium Phosphate 42.0
Magnesium Sulfate 27.0
Manganese Sulfate .179
Boric Acid / Solubor .245
Zinc Sulfate .117
Copper Sulfate .039
Ammonium Molybdate .001

Volume of Stock Solutions
2 gallons (one each)

Dilution Rate
100

pH 5.4

EC Part A 1.08, Part B 1.64

Mixed EC 2.72 diluted at a 1 to 100 ratio. ie roughly 4 ml per gallon (3.785 ml/gallon)

Total Salt Weight mg/L 3740

TDS mixed 1904

Ratios
N:K 0.4
Ca:N 1.3
K 1.2

I really do not know what any body wants in the way of information or training etc. but this is s a simple start.

I can teach anyone to formulate mathematically, by using tables or by using a spraed sheet. But you need to realise that without a purchases software package hand calculations (mathematical) are a PITA, but doable. Spread sheets make it easier but most free spread sheet programs ask for ppm's so you need to have access to ppm analysis or do the math to convert to ppms. Most commercial formulas except GH and AN are readily available. GH has most available, however for either AN or GH getting PPM amounts for supplements is much more difficult. Ant yone that has any of the major brand labels with a compltete nalyisis listing all % or ppms I v can easily do the calculations for mixing amounts etc if you will please post the information on the label. A manafacturer can not scream about the reposting of inforation already made public even if they are now with holding that information. Even MSDS 's are often enough to make up the formulation and miixing recipe. For an example, Flairform Pythoffs MSDS is sufficient to use for making a generic Phythoff preparation. Th pH up and down MSDS"s are adequate for a mixing recipe for pH up and pH down. So any such data will be helpful for this thread.

Darkdestruction420: This is a great idea. lets hope we can get some interesting discussion going.


Uncle Ben: Great Links! I especially liked "The concept of nutrient antagonism". I see many growers shooting for a total ppm when really they should also be looking at ratios.

Fatman7574: Are those ratios of N:K, Ca:N and K you listed the best for MJ? By the way where do you get all those chemicals in a major city without looking like a terrorist?

According to Botanicare these are ranges to keep your nutrient solution for each elementnot necessarily MJ)


N 160 – 250ppm
P 100 – 200ppm
K 250 – 350ppm
Ca 160 – 280ppm
Mg 45 – 75ppm
Fe 2 – 7ppm

Also I have a conversion for converting nutrient percentage to ppms, liquid nutrients only. Works for any brand name. These are the approximations.

1% N = 14 ppm (5ml of nut sol/gal)
1% P = 6 ppm (5ml of nut sol/gal)
1% K = 11 ppm (5 ml of nut sol/gal)
1% Ca = 13 ppm (5 ml of nut sol/gal)
1% Mg = 12 ppm (5ml of n. sol/gal)
0.1% Fe = 1.5 ppm(5ml of nut sol/gal)

Good stuff!

fatman7574 said:

Ratios
N:K 0.4
Ca:N 1.3
K 1.2

I really do not know what any body wants in the way of information or training etc. but this is s a simple start.

Click to expand...

Me and another guy were kicking around pervasive hydro NPK ratios a bit in another thread. Why is it that almost ALL cannabis specific hydro foods have a value of N far less than K? Does anyone have any studies to show that K is not readily available under hydro conditions? For instance, I wouldn't be caught dead subjecting my plants to the "Lucas formula": 1.7-3.3-4

Dyna-Gro doesn't follow the herd, and they've been in hydro plant food production biz for forever. Their Foliage-Pro is a 9-3-6, which has been a standard NPK for most foliage plants as long as I can remember. Their Liquid Grow is a 7-9-5 and they also make a 10-5-5.
http://www.dyna-gro.com/Website%20pdf%20Files/competitive_analysis.pdf

UB

hymem said:

Darkdestruction420: This is a great idea. lets hope we can get some interesting discussion going.


Uncle Ben: Great Links! I especially liked "The concept of nutrient antagonism". I see many growers shooting for a total ppm when really they should also be looking at ratios.

Click to expand...

Yep, see my previous post and hundreds of others. Where people screw up is by making this simple gardening drill as confusing and complex as they can.

UB

I would have a hard time saying any one formulation is best for marijuana, because it is a simple fact that many, many formulations produce the same results but do not have the same ratios. Saying that 10-10-10 is better than 5-10-10 is not not scientifically proven nor do simple empirical results based upon size or yield shown that to be true. There are too many variables involved to even produce a testing ting method to prove that 10-10-10 for example is better than 5-10-10.

There have been millions or billions of plant leaf samples tested and the best that the worlds top horticulturalists have ever come up with is a recommended "ratio range" for hydroponic growing of the most common green house agricultural products. The nutrient manafacturers manafacturers selling pot formulations do not do the testing of plant leaves or grow by standard testing methods that produce any real repeatable test results yet alone field results. Many, many y marijuana seed growers do better, testing than the top marijuana nutrient manufacturers. many commercial pot growers also do better testing. But then they usually tests for the needs of the growing conditions they provide and upon the strains they grow. While this is beneficial if you are providing all like parameters, this seldom is the case so we still in up with recommended ratios that we try top apply to all parameters used by different growers.

It is hoped the is thread will bring such research data and empirical data to print as then the growers themselves will be able to determine their needs rather than depending on manufacturers who pick some average and report it as being best.

In general the reasons to be specific about the ratios is most often more a economic decision. If there are fertilizer available in amounts beyond what the plants roots will take yup and that the plants will use then they are excess and will just be a waster of money in having them present. Secondly there is the issue that the extra unused fertilizer salts cause a rise in the EC as other nutrients are added so that for the same EC a lower concentration of the needed fertilizers will be available as less will be added of the more readily used ones. The third problem is in maintaining a balance that provided a readily manageable pH. While most problems can be managed well by just using a nutrient that is initially well balance and just dumping it and replacing it often, that can become quite expensive. Even the best fertilizers sold are not able to provide the beast ratio for all strains or all growing conditions so really most formulation marketing schemes are just that marketing schemes. The only real manner of complete nutrient management is through drain to waste system using frequent testing of in put nutrient pH and ppms as well as drained nutrient pH and ppms. In general this is what most research data is based upon when down by top researchers.

I had really hoped that this thread did not come down to a comparison of this brand does better than that brand. Actually I would hope that we could all reach a consensus that such posts would be edited out by the mods. If some one has empirical data beyond I used this and it worked better then of course that should be posted. However, without posting supporting empirical and base data such as this: growing method, strain, time periods, temperatures, lighting, humidity, lighting cycles, and this nutrient at this pH and EC at these stages produced these results and exhibited these problems, then the opinions really have no value.

The ratios shown are just the ratios for that individual formulation. Formulation data garnered from many, many "marijuana formulations, fall within the standard ratios used in other hydroponic ratios recommendations made by research by

These are the general ratio recommendations as posted by major research horticulturalists in regard to solution strengths . As can be seen they are pretty broad.

Figures are based upon ppm in solution:
N 100-400 Fe 0.5-6
P 10-100 Mn 0.3-4
K 100-650 B 0.1-0.8
Mg 10-95 Zn 0.1-0.5
Ca 70 -300 Cu 0.005-0.1
S 20-250 Mo 0.02-0.07

Ratios:
N 3-8
P 0.25-1.5
Ca:N 0.8-1.2
Mg:N 0.1-0.4
P:S 0.6-1.0

When looking at ratios a ratio like N 3-8 means the standard recommendation is that for each part:
Nitrogen there will be 3 to 8 parts Phosphorus etc.

Uncle Ben said:

What is plant nutrition?
http://retirees.uwaterloo.ca/~jerry/orchids/nutri.html

Nutrient excesses and deficiencies
http://www.ces.ncsu.edu/depts/hort/consumer/quickref/fertilizer/nutri_def.html

The concept of nutrient antagonism
http://www.totalgro.com/concepts.htm

Uncle Ben

Click to expand...

Coming to class for this thread. Good Links.

Commercially supplied data:
http://www.cropking.com/artin

Their fertilizer page:
http://www.cropking.com/HydroponicSupplies/index.php?main_page=index&cPath=264&zenid=23d6b3626b88b51218a949547f254313

Marijuana Book Integral Hydroponics Author G. Low articles relating to nutrients

Some hydro hype debunking:
http://www.integralhydro.com/advancednutrients.html

Plant Growth Regulator Formulas (copy written ie. Do Not post article copies or recipies):
http://www.integralhydro.com/plantgrowthregulators.html

I really couldn't even guess at why the major Pot nutrient manafacturers do what they do. I have simply found their products will work. I have never found AN or GH products to work best, nor with the least amount of problems or needed supplements and adjustments. They are simply average products.

The below listed formulation is what I am presently using for veg and flower. Plus trace nutrients not shown. It works very well on drain to waste systems and recirculated systems that are adjusted regularly and changed out regularly. I have rum full veg without change outs and full budding cycles without changes with minimal drops in yield. I used them for several years using pH analyzer/controllers and conductivity analyzer/controllers. They worked in my opinion a great deal better than the major manfacturers products normally touted in the forums. They are quite close to the Dyna-grow foliage pro. Many people just refer to it as the general 2:1:3 formulation. I do go heavier on the Magnesium as the Flora grow is at 50 ppm and I find that I have to add a lot of pottasium hydroxide during the last two weeks of budding with the lower magnesium levels. Dyna-gro Flora has its calcium at 200 ppm. The trace element concentration levels I maintain are consistent throught out the grow. I have also tweekedthe ratios so as to provide matching EC, TDS and Ph betwwen veg and budding as I found it caused less lags in growth during switch out of nutrient formulas. Plus it allowed not having to readjust the controllers or ph adjustment solutions etc. I had a computer program to do the iterations needed for the adjustments so it was basically a matter of just entering a few number inputs. I have not found any free spread sheets that will do the adjustment though. Todays software makes the days of manual calculations seem so long a go.

Would I recommend Flora Grow over GH or AN. I can say I have mixed nutrients for over 25 years and as far as I have seen the formulations I have come up with over the years that I have found perform the best for me so far are very near that of the Foliage Pro, not that of GH or AN. Presently I am beginning to work with fertilizers for high pressure aero and atomized aeros. Time will tell what happens there.

Bloom

PPM
Nitrogen 242
Phosphorus 86
Potassium 378
Magnesium 98
Calcium 194
Sulfur 130


Ounces

Part A
Calcium Nitrate 68.0
Potassium Nitrate 24.7

Part B
Potassium Nitrate 24.7
MonoPotassium Phosphate 28.8
Magnesium Sulfate 70.0

Volume Of Stock Concentrated Solution (gallons) 5
Dilution Rate 100
pH 5.8
EC 2.7
TDS 1904

Veg

ppm
Nitrogen 264
Phosphorus 81
Potassium 288
Magnesium 92
Calcium 259
Sulfur 122

Ounces

Part A
Calcium Nitrate 17.1
Potassium Nitrate 3.2

Part B
Potassium Nitrate 3.2
MonoPotassium Phosphate 5.1
Magnesium Sulfate 12.4

Volume of Stock Solutions (gallons) 1
Dilution Rate 100
pH 5.8
EC 2.7
TDS 1904

fatman7574 said:

Commercially supplied data:
http://www.cropking.com/artin

Their fertilizer page:
http://www.cropking.com/HydroponicSupplies/index.php?main_page=index&cPath=264&zenid=23d6b3626b88b51218a949547f254313

Marijuana Book Integral Hydroponics Author G. Low articles relating to nutrients

Some hydro hype debunking:
http://www.integralhydro.com/advancednutrients.html

Plant Growth Regulator Formulas (copy written ie. Do Not post article copies or recipies):
http://www.integralhydro.com/plantgrowthregulators.html

Click to expand...

Some really interesting links!

Damn, I didn't think you could get the EC that high. I suppose regular flushing and all... Is the difference in growth very noticeable at a solution of a much lower EC say 2.0? I also am wondering as how much dialing in those numbers help as opposed to say AN. I'm new and in this game so I got that oil. When I run out I am planning on making my own fert.

I also broke down Sensi A and B...Using the nute calc and I also scaled it up to compare to what you have because I was a bit curious in general.

Part A Part B Total

Nitrogen ppm
1)Nitrate 34 18 52
2)Ammonium 2 2 4
3)Urea 31 25 56
4)Total N 67 25 92
5)Phosphorus 17 17
6)Potassium 85 85
7)Magnesium 18 18
8]Calcium 45 45
9)Iron 2.16 2.16
10)Manganese 0.9 0.9
11)Molybdenum0.02 0.02

Above at 600 ppm suggested feeding on label

Then the comparison to yours I think the numbers were easy at 1890 ppm

4)Total Nitrogen 289.8 (264)
5)Phosphorus 53.55 (81)
6)Potassium 267.75(288]
7)Manganese 56.7 (92)
8]Calcium 141.75(259)

^^^ Quite a difference, especially at high concentrations - Ca and Mgn large range there...

Do certain strains have much different ratios/needs than others? Oh and how much do you usually pay for fertilizer and how long does that last you? I plan on doing some experiments way later on with clones doing different ppms for my strain to see what is ideal. Cause I just want to commercial 1 strain and get the best I can out of it. Thanks. Bookmarked all those links haha...Note to self next time use brackets next time...damn smiley faces lol

Fatman: You show your TDS to read 1904 but if you count up all the nutrients you mention it adds up to around 1104ppm. I know the micronutrients cant make up the difference so why are the numbers different? Thanks for all the great info.

The ppm is based upon measured amounts of chemical added to form the concentrate. ie 1 mg/L is 1 ppm. The TDS is a simple concversion of the EC reading. An EC reading is based upon the electrical conduction capacity of an ion. However ions have different conduction capabilities. The EC meter uses a preprogrammed conversion factor (number) to convert between the tow. The TDS is not acco uratte as different ions conduct difeerently and the meter does not read each ion type seperately but dreads the total EC and then spits out anppm based y upion the EC of ust one o ion.

Conductivity of Some Common Hdroponic Nutrients at 2000 ppm

Calcium Nitrate EC =2
Potassium Nitrate EC= 2.5
Magnesium Sulfate EC = 1.2

The scientific community has just chosen conversion factors as standards. ie TDS as a meter out put is a scientifically based ESTIMATE based uopn the conductivity of just one ion applied to all ions present.

fatman7574 said:

The ppm is based upon measured amounts of chemical added to form the concentrate. ie 1 mg/L is 1 ppm. The TDS is a simple concversion of the EC reading. An EC reading is based upon the electrical conduction capacity of an ion. However ions have different conduction capabilities. The EC meter uses a preprogrammed conversion factor (number) to convert between the tow. The TDS is not acco uratte as different ions conduct difeerently and the meter does not read each ion type seperately but dreads the total EC and then spits out anppm based y upion the EC of ust one o ion.

Conductivity of Some Common Hdroponic Nutrients at 2000 ppm

Calcium Nitrate EC =2
Potassium Nitrate EC= 2.5
Magnesium Sulfate EC = 1.2

The scientific community has just chosen conversion factors as standards. ie TDS as a meter out put is a scientifically based ESTIMATE based uopn the conductivity of just one ion applied to all ions present.

Click to expand...

Thanks. It just doesnt seem reasonable to use a scientific instruments with so much error. Your TDS measurement is off by 800ppm! Thats enough to kill your crop. Whats the point of even mentioning TDS if it is so inaccurate?

The equipment does not read in error. It just not read in specifics. For an example. A nutrient sample reads an EC of 2. It could be 2000 ppm of Calcium nitrate or it could be 1600 ppm of Magnesium sulfate. It could be many different combinations of concentrations.

TDS, PPM, and EC

If you have any desire to mix your own fertilizers, it is important that you have at least basic understanding of these terms

Electricity is conducted due to the presence of ions (electrically charged) in a solution. The ions get there by introduction of salts via our ferts!

EC (electric conductivity) is a representation of how much potential a solution has to conduct electricity...SO, by testing the ability of a solution to conduct electricity, we can indirectly determine the amount of salts present....thereby knowing if we have the right concentration of ferts.

E.C. is a measure of salinity by measuring its conductivity. You want an E.C. under 2.0

Despite many peoples natural aversion for ppm measurement, it is a good idea when mixing ferts as a beginner.

TDS is a measurement, by weight, of the Total Dissolved Solids in a solution and is measured in PPMs (Parts Per Million). Basically, when you hear someone say they introduce nutrients at a rate of 500 PPMs, it means that they have 500 milligrams of solid dissolved in a Liter of water.

You can figure the PPM of your ferts one of two ways.....you can precisely measure the ferts and water you mix together...or you can make a solution and measure the PPM of IT. The shortcut lies in hand-held meters which measure the EC of a solution and then apply mathematical conversion to the EC figure to arrive at PPMs. Keep in mind, even this is an approximate measurement...but plenty accurate for growers!

Some meters actually display the EC AND the PPM readings. Some only express the EC value and this can be tricky because European and American made meters measure at different rates.

An American device that displays an E.C. of 1.0 has 500PPMs.
A European device that displays an E.C. of 1.0 has 640PPMs.

So if your device only displays E.C., use a bit of simple algebra and set the two given equations equal to each other. For example, let's say your E.C. reading is 1.2.

Using the known ratio given just above, just cross multiply to solve for x to get the unknown ppms.
1.0/500ppm=1.2/X, so (1.2 *500)/ 1.0) = X
X=600
Therefore 600PPMs.

If you want to figure out the PPMs yourself, its pretty easy. Each 1 gram of fertilizer per liter of water gives 10 PPMs of each given nutrient per percentage point. Sounds clumsy, wish I could state that better....here's an example.

Use 1 gram of SuperPhosphate 0-20-0 in a liter of RODI water. The solution would have 0 ppm of N, 200 ppm of P, and 0 ppm of K. Also keep in mind that tap water already has dissolved solids...most likely anywhere between 200-400 PPMs. Use RODI water when possible...0 PPMs!!



Short of testing for each fertilizer individually, an EC or TDS meter is the cheapest, easiest method of providing an approximate ppm. For an example the cheapest ISE (ion specific electrode) I have seen retails for about $250. It is nearly as adequate as a laboratory grade. The calcium ISE is the only ISE I have ever seen that selss chepaly and y that is because the volume sold to reef aquarium keepers is large enough for volume sells at low mark upos. It is a Pin Point Calcium Monitor Meter at $149.95. I use laboratory grade ISE's such as the Thermo Orion ISE that sells for over $700 for just the electrode (probe). The meter costs equally as much or more.

I try to buy from Ebay as much as possible. I also use ISE testing for Nitrate, ammonium and phosphate. Phosphorus I check with a Hach spectrophotometer as well as iron and chlorine. Magnesium I test by titration as it is part of a hardness test that confirms the calcium test and also tells me the magnesium and the bicarbonate hardness.

In general I mainly just check, ammonium, nitrate, pottasium, chlorine and iron. Except when changing strain, nutrient formulations, EC or any major parameter I usually just monitor EC and pH.

I would likely not own the test equipment I have if it was not tax deductible due to my profession and if I did not acquire most of it ion eBay. I also have slat water reef aquariums so it sll gets used fairly often. It is nice buying a new, never used ion specific probe that usually sells for $800 or more for $20 to $100. I recently bought an ammonium and a nitrate probe sold together for $28.77. They retail for over $800 each generally. The reagents for testing with the spectrophotometer usually run about 20 to 25 cents per test.

If you ever get that interested in that aspect of growing send me a PM. I have lots of testing equipment, meters, controllers and analyzers, peristaltic pumps etc.

To ease the tension of some readers of this thread, please realise that just because a nutrient formulation is formulated at say an EC of 2.7 and a TDS of 1900 ppm and at a concentration at 100X doesn't mean that the nutrients should be used at 2.7 ppm or 1900 ppm. That is just the final outcome of a fertilizer not a dosing amount. A 100X concentration with an EC of 2.7 and 1900 ppm merely means that the conentrate when diluted 1 to 100 will provide a final nutrient solution with thoat EC measurement. The EC level that you use or the TDS ppm can vary greatly from mix to mix based upon the actual formula analysis as different compounds have different masses and different conductivities. So really the formula EC and TDS is just a way of easily indicating an estimate of the amount by weight of salts. This is simplier than actually look at all the weights etc and makes it easier for you to compare the ferlizer formula toa retail formula that only provides a guaranteed analysis. So if a retailer says the fertilizer is 5-5-5 and you mix a 5-5-5 fertilizer formulated for 100X the gallon they sell you should provide a mixed fertilizer at the same EC if it is labeled at 100X. Unfortunitely not many Pot fertilizer manafacturers are ethical/fair enough to list the concentration but instead just give mixing directions.

As for what I use for a strength. I seldom use a TDS higher than around 650. That puts the EC down around 0.92 That means I actully use the formulation at a dilution ratio near 1 gallon to 300 gallons. You can afford to change your reservoir weekly easily at that rate. Or after advancement to something like a high pressure aero or air atomized aero simply run a drain to waste system. In all actuallity your RO water generation costs should be more costly then the fertilizers used.

GrowingfortheGold said:

Part A Part B Total

Nitrogen ppm
1)Nitrate 34 18 52
2)Ammonium 2 2 4
3)Urea 31 25 56
4)Total N 67 25 92
5)Phosphorus 17 17
6)Potassium 85 85
7)Magnesium 18 18
8]Calcium 45 45
9)Iron 2.16 2.16
10)Manganese 0.9 0.9
11)Molybdenum0.02 0.02

Above at 600 ppm suggested feeding on label

Then the comparison to yours I think the numbers were easy at 1890 ppm

4)Total Nitrogen 289.8 (264)
5)Phosphorus 53.55 (81)
6)Potassium 267.75(288]
7)Manganese 56.7 (92)
8]Calcium 141.75(259)

^^^ Quite a difference, especially at high concentrations - Ca and Mgn large range there...

Do certain strains have much different ratios/needs than others?

Not to a huge extent until you compare Increased nitrogen demands of large sativas (tall) versus small indicas (short). Growing systems and physical parameters such as lighting, humidity and CO2 levels have much more effect. The major difference between the nutrient needs of the different strains is mostly centered around the bushinees of the plant and the fact that lighting PAR is going to be different with different plant t strians and phenoy types as the cam nopy will be different, the heights will be different and the bushiness will be different. Different PAR lighting on different percentages of the different plants make large differences in nutrient uptake. ie if two thirds of the strain A is receiving low Par then that plant will have different uptakes then a strain B that in the same room has foliage, shape, and height attributes where only 25% receives low PAR.

Oh and how much do you usually pay for fertilizer and how long does that last you?

I supply my own nutrients plus those for 7 large commercial growers so I buy pallets of the major nutrients. So they typically cost about $0.35 to $1.00 per pound except for the monopotassiun phosphate about $1.50 per pound. An average formulation is less than 3 pounds of fertilizers. That is for fertilizers at 2.5 EC or higher ie always at least 100X. Even with trace nutrients the cost is not over $5 per gallon. Figure it that makes 300 gallons it is less than 2 cents per gallon for fertilizer. Even with a commercial RO filter run at 200 psi and usinf a divertor valve to reuse 70% of waste water my RO water cost is more than the fertilizer cost. MY RO cost is about 8 cents per gallon as I have to pay sewer fees on all purchased water.

I plan on doing some experiments way later on with clones doing different ppms for my strain to see what is ideal. Cause I just want to commercial 1 strain and get the best I can out of it. Thanks. Bookmarked all those links haha...Note to self next time use brackets next time...damn smiley faces lol

Click to expand...

I guess I need to write something up on ammonium nitrogen.

As far as the calcium and magnesium issue. That pretty much is a simple matter as look at what is an antgaonist to waht as afar as fertilizers.

Fertilizer Excess ******* May Cause Defficiency of

Nitrogen ***** Potash
Phosphorus *** Nitrogen, Calcium, Magnesium **** Calcium
Calcium **** Magnesium, Boron
Iron **** Manganese
Manganese ****Iron

As you can see using too much calcium or magnesium really only antagonize each other. The only thing having slightly larger calcium levels really adversely effect si it raises the EC. If the EC is raised too much due to the excess calcium and magnesium there will of course be lower levels of the other nutrients meaning you will have to will have to add nutrients more often and change the reservoir regularly.

While excess calcium and magnesium basically means hard water, unless you go extreme hard water is really not that hard to deal with. It does make it hard to maintain nutrient reservoirs for long periods of time without change outs. however, if you mix your own nutes there is no reason to ever need to not change out the reservoir every week to 10 days.

Just remember plants do not like high EC nutrients, so if you use up to much of the allow able salts for your allowable EC with calcium and magnesium then you will have little room for you other fertilizers salts and not go over your desired EC. Plus too high calcium and magnesium means they will accumalate in your reservoir, so each day when you top the water off and add a liitle nutes your adding both more fertilizers you need and more calcium and magnesium you dion't need. If you change out regularly this will not matter. If you do not change out regularly then you will have problems. The formulations with the higher calcium and magnesium perform better but they do not allow the cheaper growing method of seldom or never changing out your reservoir.

Great stuff. A few points merit highlighting:

To ease the tension of some readers of this thread, please realise that just because a nutrient formulation is formulated at say an EC of 2.7 and a TDS of 1900 ppm and at a concentration at 100X doesn't mean that the nutrients should be used at 2.7 ppm or 1900 ppm. That is just the final outcome of a fertilizer not a dosing amount........Unfortunitely not many Pot fertilizer manafacturers are ethical/fair enough to list the concentration but instead just give mixing directions.

Yep,you still have to read your plants and understand their requirements at any given point in time. IOW, dosage charts suck and many times you aren't even told the NPK values by the pot vendor. Go to one site and they might have one ratio while another might have another ratio for the same food. This pot industry can be about as half a$$ed it gets.

Well done:

Just remember plants do not like high EC nutrients, so if you use up to much of the allow able salts for your allowable EC with calcium and magnesium then you will have little room for your other fertilizers salts and not go over your desired EC. Plus too high calcium and magnesium means they will accumalate in your reservoir, so each day when you top the water off and add a liitle nutes your adding both more fertilizers you need and more calcium and magnesium you dion't need. If you change out regularly this will not matter. If you do not change out regularly then you will have problems. The formulations with the higher calcium and magnesium perform better but they do not allow the cheaper growing method of seldom or never changing out your reservoir.