The Lounge : Growers Round Table Discussion Thread

This will be a continuation of the SlowN Thread:
https://www.icmag.com/ic/showthread.php?t=331317

Please post grows, soil mixes, soil-less mixes, nutrient mixes etc. that are in line with the topic. (I am trying to keep the term "SlowN method" out of this)

This thread is to grow the Community, If you can't get in line with that, Please stay out.

I will personally PM anyone that is out of line in this thread before contacting a Mod. If you feel someone is out of line, PM me first.

Soil (and Nutrition!) Math and Glossary 101:

TEC - Total Exchange Capacity - Of all particles and receptor sites in a mix, a value which demonstrates the size and ability to retain or make available cations and anions.
Cations - Elements or ions, of which the net result is a positive charge.
Anions - Elements or ions, of which the net result is a negative charge.
CEC - Cation Exchange Capacity - "The total capacity of a soil to hold exchangeable cations. It influences the soil's ability to hold onto essential nutrients and provides a buffer against soil acidification."
EC - Electrical Conductivity (measured in micro-siemens, µS/cm, "measure of the concentration of dissolved solids which have been ionized in a polar solution *cough* water")
ppm/ppb - Parts per million/billion
mEq - milli-equivalents/(typically of 100 grams of soil or mix content)
Bulk Density = mass of dried soil per volume of that soil when field ready (dry weight of the soil and divide by total volume). Usually expressed in grams per cubic centimeter. - biggreg



Percent Nutrient Saturation - Each elements individual presence in the TEC
Percent Base Saturation - The sum of a groups (Ca ++, Mg ++, K+, Na+, H+, [sometimes Fe ++, Zn ++, Cu ++, Mn++, Al +++]) percentage or presence as cation's in the TEC

M3 - Melich 3 testing method- an extractant which when combined with soil samples will separate elements from each other and organic material to determine nutrient saturation.
AA @ 8.2 - Ammonium Acetate/pH 8.2 testing method -an extractant used to determine nutrient saturation which does not overestimate Ca++ content, which M3 may.

Calculating Base Saturation - I'll put it in my own words someday but for now, the Midwest link will do nicely.

https://midwestlabs.com/wp-content/u...Saturation.pdf

Calculating PPM of pure substances (>90%)

1 ppm = 1 mg/L

To know the concentration, replace X and Y, (X mg / Yml) x 1000 = Z ppm
To know the amount of solution to make to get a certain ppm, replace X and Z, (X mg / Z ppm) x 1000 = Y ml
To know the quantity of powder to use, replace Z and Y, (Z ppm x Y ml) / 1000 = X mg
For example: 100mg of GA3 in 200ml of water gives you 200ml at 500 ppm (part per million). 100mg of GA3 in 400ml of water gives you 400ml at 250 ppm.

Calculating PPM and percentages for a specific nutrient/product (example/starting point is Agsil 16) ~Avenger
Examine your label
https://www.certisusa.com/pdf-labels/agsil16H_label.pdf

Silica (SiO2)…………. 53%
Potassium (K2O)........32%

52.8 (53% as listed by AgSil) times ten equals 528 ppm from one gram Agsil 16h in one liter final volume solution

divide 528 by 3.785 and you get 139.5 ppm of SiO2 in one gallon final volume solution from one gram Agsil 16h

[A total molar mass of SiO2 is 60.0843 or Si (28.0855) + O2 (31.9988)]
SiO2 is [sic]therefore: 46.75% silicon(Si): 53.25 oxygen (O), so ...

139.5 times 0.4675= 65.22 ppm silicon (Si) from one gram Agsil 16h in one gallon final volume solution.

65.22 x 0.7 = 45.7 ppm Silicon from 0.7 grams in one gallon final volume
65.22 x 1.25= 81.5 ppm Silicon from 1.25 grams in one gallon final volume

((the solubility limit is ~120 ppm SiO2[~56 ppm Si]))

PPM, Dilution, Concentration, Molarity: https://delloyd.50megs.com/ppm.html
Soluble or Not: https://en.wikipedia.org/wiki/Solubility_chart
Solubility Limits Table and tutorial: https://www.ausetute.com.au/soltable.html
Solubility Limits Table (exhaustive): https://en.wikipedia.org/wiki/Solubility_table
Concentration/Percentage Converter: https://www.endmemo.com/convert/conc...percentage.php [e.g. SiO2 at .012 g/100ml = 120ppm]

Additional Equations and Circumstances: Bulk Density and Conversions

Pages 1-4:https://www.icmag.com/ic/showthread.php?t=335672
Practice Problems: Cation Exchange Capacity: https://lawr.ucdavis.edu/classes/ssc...problems02.htm
Practice Problems/Equations: Porosity and Bulk Density: https://lawr.ucdavis.edu/classes/SSC...ts/pset01.html
Molecular Mass Calculator: https://www.convertunits.com/molarmass/
Volume Conversion Calculator: https://www.endmemo.com/convert/volume.php
Area Conversion Calculator: https://www.endmemo.com/convert/area.php
Cubic Yard Calculator and Tables (scroll down)1) https://www.harvestpower.com/product...pe-calculator/ (2) https://www.calculatorsoup.com/calcu...calculator.php
(lesser used) Cubic Ft. to Sq. Ft.: https://www.endmemo.com/cconvert/ft3ft2.php

I'll edit often and tidy up. Any resources or links that should be easily accessible will be included.

Fertilizers, sources, percentages, uses: https://people.umass.edu/~psoil120/guide/chapter7.htm
Capacities of common substrates: https://www.extension.uidaho.edu/nur...CN%20ratio.PDF
Organic Soil vs. Mineral Soil: https://www.icmag.com/ic/attachment....9&d=1480837564
Biology and FAQ: https://content.ces.ncsu.edu/extensi...n_heading_7243
Measuring Moisture Content in Leaves and Compost: https://compost.css.cornell.edu/calc...e_content.html
The difference between M3 and AA testing (The USGA article): https://gsrpdf.lib.msu.edu/ticpdf.py...oil-3-4-11.pdf
Tiedjens, Albrecht, and more: https://soilanalyst.org/category/authors/
Further Reading: https://soilanalyst.org/category/textbooks/

1-2-1, balanced micros and a butt ton of gypsum! Working great for my indoor run. A week or so from harvest, I will post a picture of a bud or two when its all done. Redonk quality.

Saved.

Any chance someone could post the formula for calculating how many ppms of each element are coming from a compound?

I.e.
Diamond K gypsum contains 22.5% Ca and 18% S. How would I figure out how much Gypsum to use if I wanted to add 250 ppms of Ca to a yard of soil?

https://www.spectrumanalytic.com/support/library/ff/CEC_BpH_and_percent_sat.htm

Atomic weight divided by valence electrons multiplied by 100; then double that to achieve lbs/acre, according to their table.

.

subb'd

Alg0rithm said:

Any chance someone could post the formula for calculating how many ppms of each element are coming from a compound?

Click to expand...

NP

100% w/w = 1,000,000 PPM =One million parts per million.

10%= 100,000 PPM = 100 gr/L
1% = 10,000 PPM = 10 gr/L
.
.
.
0.0001 miligram per litter = 1 PPM

So if we have 100g pure gipsum salt (CaSO4) we have 28g of Ca+ and 72g of SO4-.
When the molecular mas of Ca is 40, and the molecular mas of SO4- is 98.

if we take all the salt and add it to 1 Litter of water we will have a solution that has 4% Ca (40/1000) or 40,000 PPM of Ca.

growingcrazy said:

That is 500 lbs to the acre of Ca.

500 / .225 = 2,222 lbs / acre of Diamond K gyp. to get 500 lbs or 250 ppm per acre...

43560 square feet per acre / 2 = 21,780 cuft in an acre, a furrow deep. (6.7")... I use 6" to calculate.

21,780 / 27 = 806 yards per acre

2,222 / 806 = 2.75 lbs / yard to get to 250 ppm or 500 PPA, pounds per acre.

So 2.75 lbs per yard of soil.

On a peat based soil-less mix I would cut that number in half.

If anyone would like to correct that, please show me.

Edit: I like to use ppm for calculating fert. requirements, but use meq calculations for balancing. I am sure a lot of you already know that, but some do not.

Click to expand...

I can dig it- lemme see if I got this right

Desired PPM- Double it to get PPA

Desired PPA = Usable lbs/acre
% of element

Usable lbs/acre = Amount/ft of soil (adjust for cu. yd.)
furrow cu. ft./acre

Does that jive?

bsgospel said:

I can dig it- lemme see if I got this right

Desired PPM- Double it to get PPA

Desired PPA = Usable lbs/acre
% of element

Usable lbs/acre = Amount/ft of soil (adjust for cu. yd.)
furrow cu. ft./acre

Does that jive?

Click to expand...

Doubling it is a huge assumption. You would have to use the bulk density of the soil in the correct units. Although for all intensive purposes doubling is adequate.

Got it- so to get to bulk density we take the dry weight of the soil and divide by total volume- and then... multiply that by the desired PPM?

No you by use the bulk density and you use it to get the weight of the soil per acre than use that to get the factor that you would use to get parts per mil to lbs per acre.

.

growingcrazy said:

It is assumed that field soil weighs 2,000,000 lbs per acre to the depth of a furrow slice. This is where the parts per million come into play...

Most Farmer's will use that number and assume 40,000 sqft per acre to make math easier.

This is for field soil...aka real soil.

To be 100% accurate with a soil less mix you would need to know what a cubic foot of it weighs. Then from there you can determine the weight of an acre of that soil and get your amendments very close.

Now... I don't do all of that... If I am in field soil and we are fertilizing to a depth of 6" I use the normal method, If your fertilizing to 12", double your numbers.

In soil-less mixes I have always just halved the 6" number to account for the light weight medium...I have always been very close to my numbers..whether that is luck or not... I have been using the k3 from spectrum and see very little difference in the tests coming from MSU that are not weighed.

Someone that actually weighs there mix and does the calculations that way should chime in and let us know how they do it.

Click to expand...

Well for starters we use 43560 square feet per acre.

But other than that you're spot on. I guess the only thing about the bulk density is you convert it into lbs per acre. We just weigh it to grams per cup than convert.

In n field soil, this math is important but where you sample and what other assumptions you make are more important cause you use those numbers in you final calculations

I agree, I always use 43,560.

Lots of old timers still don't around here...maybe it is something about calculators...

growingcrazy said:

I agree, I always use 43,560.

Lots of old timers still don't around here...maybe it is something about calculators...

Click to expand...

I mean it kinda makes sense. 3500 is a very little percentage of 40000 so it appears negligible. But it's not that negligible really. Especially at larger scales.

It looks like We are alone here ...

Which route are we taking here? Are more people interested in soil-less mediums or real soil?

Soilless this year

I would love to see some ideas for soiless peat and coco mixes - specifically some recommendations for gypsum and borax amendment amounts for these mixes.

I blindly played with gypsum and borax all year on a multitude of strains in a peat/perlite mix in 5 and 7 gallon containers. I saw the good, the bad and the ugly, but saw enough good to know that this is something I have to figure out.

Ideally I'd love to see ideas specific enough to be input into a spreadsheet so one could enter the details of the mix they wanted to use and the spreadsheet would calculate the amounts of amendments to add for a decent balance.

Maybe that's a pipe dream, but I'd like to see us work toward that end.