Bucket Chemistry 101

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Bucket Chemistry 101

• Bodie Pennisi, and Paul Thomas
• Extension Horticulture Specialists
• The University of Georgia

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Bucket Chemistry
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(No Transcript)
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Fertilizer Problems Are Not That Bad !
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The Way To Tackle Them Is
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Greenhouse Crops and Fertilizer
Recommendations
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Fertilizer Stock Tank
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PROPORTIONER A device used in a fertigation
system to control the rate of fertilizer applied
through the system.
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Fertilizer Injector or Proportioner
Stock Fertilizer Tank
1 part stock solution
Water line
100 parts of water
Injector ratio 1 100
Irrigation line to plants
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Fertilizer Injector or Proportioner
Stock Tank
Water line
1 part stock solution
5 gal 25 50 100 200 500 etc.
x parts of water
Injector ratios
To get from ratios to percent (1/50) x 100 2
150 1100 1200 1500
2 1 0.5 .01
To get from percent to ratios 100/2150
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Fertilizer recommendations for greenhouse crops
are given as either ppm of a specific fertilizer
nutrient or in pounds and ounces (weight basis)
of a fertilizer formulation per 100 gallons of
water
Parts per million (ppm) One part of a
substance into one million parts of another
substance
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Things You Need To Know To Solve ppm
Problems

• Recommended fertilizer application rate.
• Example 8 ounces per 100 gal or 200 ppm
  nitrogen
• 2. Fertilizer formulation and analysis.
• Example 20-10-20
• Injection ratio
• Example 1100
• Size of stock tank in gallons
• Example 25 gallons

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Weight Basis
Example A chrysanthemum grower gets a
recommendation to apply 20-20-20 water-soluble
formulation to a final concentration of 16 oz per
100 gallons of water. How much fertilizer
should be mixed in a 25 gallon stock tank if an
injector with a 130 injection ratio will be used?
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Things You Need To Know To Solve This
Problem

• Recommended fertilizer application rate.
• 16 ounces per 100 gal
• 2. Fertilizer formulation and analysis.
• 20-20-20
• Injection ratio
• 130
• Size of stock tank in gallons
• 25 gallons

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Solution
Step 1 Adjust the rate for the stock tank
size using the following equation Equation
1 oz per 100 gal oz fertilizer per stock
tank 100 / Stock Tank Size (gal)
16.0 oz per 100 gal 4.0 oz of
20-20-20 100 / 25 gal
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Solution
Step 2 Adjust the rate for the injection
ratio Equation 2 oz per stock tank x injector
ratio oz per stock tank using injector
4.0 oz per 25 gal x 30 120.0 oz per 25 gal
_at_130 ratio
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Commercial Fertilizer (ppm)
Example A pansy grower gets a recommendation to
apply 150 ppm nitrogen using 20-10-20
water-soluble formulation. How much fertilizer
should be mixed in a 25 gallon stock tank if an
injector with a 1100 injection ratio will be
used?
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Things You Need To Know To Solve This
Problem

• Recommended fertilizer application rate.
• 150 ppm nitrogen
• 2. Fertilizer formulation and analysis.
• 20-10-20
• Injection ratio
• 1100
• Size of stock tank in gallons
• 25 gallons

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The Rule of 75
1 oz / 100 gal 75 ppm
HOW DID WE GET THIS ?
One ounce (28 grams) of any pure dry
substance that will dissolve 100 in a
volume of 100 gal equals 75 ppm
1 oz 28 g or 28,000 mg 28,000 mg 379 L
73.88 ppm ( 1 gal 3.79 L 100 gal 379 L )
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Solution
Step 1 Convert the ppm recommendation to a
weight basis using the following
equation Equation 3 desired ppm
oz fertilizer per 100 gal of fertilizer x 75
150 ppm 10.0 oz of 20-10-20 per 100 gal 20
x 75 (final solution)
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Solution
Step 2 Use equation 1 to adjust for a stock
tank size of 25 gallons oz per 100 gal
oz fertilizer per tank 100 / Tank Size (gal)
10.0 oz per 100 gal 2.5 oz of 20-10-20 per 25
gal 100 / 25 gal
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Solution
Step 3 Use equation 2 to adjust the rate for a
1100 injection ratio (In other words,
concentrate it! ) oz per stock tank x injector
ratio oz per stock tank using injector
2.5 oz per 25 gal x 100 250.0 oz per 25 gal
using a 1100 injection ratio
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You Are Done !
Solution
Step 4 Convert ounces to pounds and ounces
where 16 ounces 1 pound (dry) 250.0 oz
per 25 gal 15 lbs 10 oz 20-10-20 16 oz /lb
(. . . .in a 25 gallon stock
tank) This will give you 150 ppm with a 1/100
ratio
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Not Yet !
How many parts per million of actual phosphorus
and potassium will be applied with the 150 ppm N
from the 20-10-20 ?
Equation 4 Oz fertilizer per 100 gal x 0.75
x percent nutrient the ppm desired nutrient
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Phosphorus 10.0 oz per 100 gal x 0.75 x 10
P2O5 75 ppm P2O5
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Not Yet !
For actual phosphorus P2O5 is actually only
44 elemental phosphorus Therefor 75 ppm P2O5 x
0.44 33 ppm actual phosphorus
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Equation 4 Now lets find the potassium true
value! Oz fertilizer per 100 gal x 0.75 x
percent nutrient ppm desired
nutrient Potassium 10.0 oz per 100 gal x
0.75 x 20 K2O 150 ppm K2O in
solution For actual potassium K2O is 83
elemental potassium 150 ppm K2O x 0.83
124.5 ppm actual potassium
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Final analysis 150 ppm N 33 ppm P
124.5 ppm K

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A Test !
A poinsettia grower needs to apply 500 ppm
nitrogen using ammonium nitrate (33.5-0-0). He
also needs to treat his crop with 100 ppm
magnesium using Epsom salts (10 magnesium).
How much of each fertilizer must be added to a 5
gallon stock tank for delivery through a 0.4
injector?
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If You Got These Answers
You Were Right!
15 lbs 9 oz NH4NO3 and 10 lbs 6 oz MgSO4
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Things You Need To Know To Solve This
Problem

• Recommended fertilizer application rate.
• 500 ppm nitrogen and 100 ppm magnesium
• 2. Fertilizer formulation and analysis.
• 33.5-0-0 and 10 magnesium
• Injection ratio
• 0.4
• Size of stock tank in gallons
• 5 gallons

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Solution
Step 1 Convert the recommendation for
nitrogen ppm to a weight basis 500ppm
19.9 oz of 33.5-0-0 per 100 gal
(final solution) 33.5 x 75
Step 2 Adjust for a stock tank size of 5
gallons 19.9 oz per 100 gal 0.995
oz of 33.5-0-0 per 5 gal 100 / 5 gal
Step 3 Adjust the rate for a 0.4 injection
ratio 0.4 injection ratio is 1250 (100/ 0.4
250) 0.995 oz per 5 gal x 250 248.75 oz per
5 gal using 1250
Step 4 Convert ounces to pounds and
ounces 248.75 oz per 50 gal 15 lbs 9 oz
33.5-0-0 per 5 gal for 500 ppm N 16 oz

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Solution
Step 5 Convert the recommendation for
magnesium ppm to a weight basis 100ppm
13.3 oz of 10 Mg sulfate per 100 gal
(final solution) 10 x 075
Step 6 Adjust for a stock tank size of 5
gallons 13.3 oz per 100 gal 0.665 oz
of 10 MgSO4 per 5 gal 100 / 5 gal
Step 7 Adjust the rate for a 0.4 injection
ratio 0.665 oz per 5 gal x 250 166.25 oz
per 5 gal using 1250 injection ratio
Step 8 Convert ounces to pounds and
ounces 166.25 oz per 50 gal / 16 oz 10 lbs 6
oz 10 Epsom salts per 5 gal for 100 ppm Mg
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Nursery Crops and Fertilizer Recommendations
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Application of Granular Fertilizer to
Container Nursery Crops
Recommendation Apply 3 lbs of nitrogen per
cubic yard of medium per growing season. Nursery
Response How much Nutricote (17-6-8) do I apply
to each container of my Hollies in Trade 1-size
containers ?
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Things You Need To Know To Solve This
Problem

• Recommended fertilizer application rate.
• 3 lbs nitrogen per cubic yard
• 2. Fertilizer formulation and analysis.
• 17-6-8
• Container size
• Trade 1
• Number of containers per cubic yard
• 300

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Useful Conversions
Pounds Nitrogen/Acre/Year are converted to lbs
fertilizer/A/Yr by the following formula lbs
N/A/Yr x 100 constant lbs fertilizer/A/Yr
fertilizer
Pounds Nitrogen/cubic yard/Year are converted
to lbs fertilizer/ cubic yard /Yr by the same
formula lbs N/cu yd/Yr x 100 constant lbs
fertilizer/cu yd/Yr fertilizer
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Solution
Step 1 Convert the pounds nitrogen
recommended to pounds of Nutricote (17-6-8) 3
lbs N/cubic yard x 100 17.65 lbs
Nutricote per cubic yard 17
Step 2 Calculate pounds of Nutricote per 1
container. Remember that there one cubic yard
of medium can fill up 300 Trade 1
containers 17.65 lbs 0.0588 lbs Nutricote
per Trade 1 container 300
Step 3 Convert pounds to grams and grams to
tablespoons 1 lb 453.6 grams
1 tbs 15 grams 0.0588 lbs x 453.6
26.69 grams 26.69 grams / 15 1.78 tbs Nutricote

Final answer 2 tbs of Nutricote per Trade 1
Holly per season
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Other Useful Conversions
Milligrams per liter equal ppm mg/L ppm 1 gram
1,000 ppm 1 10,000 ppm
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Tank Mixes
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Tank Mixes
Example A grower wants to prepare a tank mix
containing 200 ppm actual nitrogen and 200 ppm
actual potassium using calcium nitrate
(15.5-0-0) and potassium nitrate (13-0-44). How
much of each fertilizer must be added to a 50
gallon stock tank for delivery through a 1100
injector?
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Things You Need To Know To Solve This
Problem
1. Recommended fertilizer application
rate. 200 ppm nitrogen and 200 ppm potassium 2.
Fertilizer formulation and analysis. calcium
nitrate (15.5-0-0) potassium nitrate (13-0-44)
3. Elemental nutrient analysis. 4. Injection
ratio 1100 5. Size of stock tank in
gallons 50 gallons
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Note When combining two or three fertilizers to
formulate a tank mix, it is usually easiest to
start with a fertilizer containing two nutrients
of interest, usually phosphorus or potassium, and
do the calculation for nitrogen last.
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Solution
Start with the potassium nitrate because it
contains both nitrogen and potassium. Since
K2NO3 contains 13 actual nitrogen and 44 K2O,
first calculate the amount of K2NO3 to add to 100
gallons to get 200 ppm actual potassium.
However, 44 is not actual K, it is K2O.
Step 1 Convert 44 K2O to actual K. Contains
83 actual K 44 K2O potassium nitrate x
0.83 36.52 actual K
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Solution
Step 2 Determine ounces per 100 gallons of
K2NO3 for 200 ppm actual potassium using equation
3
200 ppm 7.3 oz of 13-0-44
per 100 gal 36.52 x 0.75 (final solution)
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Solution
Step 3 But wait how much nitrogen was
added? Calculate by using equation 4.
7.3 oz per 100 gal x 0.75 x 13 N 71 .
175 ppm actual N
So a solution containing 7.3 ounces potassium
nitrate per 100 gallons is 200 ppm potassium and
71.175 ppm nitrogen.
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Solution
Now adjust the amount of potassium nitrate for
the stock tank size and injector ratio.
Step 4 Using equation 1 to adjust for a stock
tank size of 50 gallons
7.3 oz per 100 gal 3.65 oz of 13-0-44
per 50 gal 100 / 50 gal
Step 5 Using equation 2 to adjust the rate
for a 1100 injection ratio
3.65 oz per 50 gal x 100 365.0 oz per 50 gal
_at_ 1100 injection ratio
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Solution
Step 6 Convert ounces to pounds and ounces
365.0 oz per 50 gal 22 lbs 13 oz 13-0-44 per
50 gal for 200 ppm K 16 oz
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Solution
Step 7 Calcium nitrate (15.5-0-0) contains
15.5 nitrogen and 200 ppm total nitrogen is
required. However, the potassium nitrate
supplied 71.175 ppm N. Therefore, subtract
71.175 from 200 and apply equation 3
200 71.175 ppm 11.1 oz of 15.5-0-0
per 100 gal 15.5 x 0.75 (final solution)
Step 8 Use equation 1 to adjust for a stock
tank size of 50 gallons
11.1 oz per 100 gal 5.55 oz of 15.5-0-0
per 50 gal 100 / 50 gal
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Now You Are Really Done !
Solution
Step 9 Using equation 2 to adjust the rate
for a 1100 injection ratio
5.5 oz per 50 gal x 100 555.0 oz per 50
gal using 1100 injection ratio
Step 10 Convert ounces to pounds and ounces
555.0 oz per 50 gal / 16 oz 34 lbs 11 oz
15.5-0-0 per 50 gal for 200 ppm N