Bucket Chemistry 101 Bodie Pennisi, and Paul Thomas Extension Horticulture Specialists The University of Georgia

Bucket Chemistry

Fertilizer Problems Are Not That Bad !

The Way To Tackle Them Is …

Greenhouse Crops and Fertilizer Recommendations

Fertilizer Stock Tank

PROPORTIONER PROPORTIONER A device used in a fertigation system to control the rate of fertilizer applied through the system.

Stock Fertilizer Tank Injector ratio 1 : 100 Fertilizer Injector or Proportioner Water line Irrigation line to plants 1 part stock solution 100 parts of water

Stock Tank 1:50 = 1:50 = 1:100 = 1:200 = 1:500 = Water line 1 part stock solution x parts of water 5 gal etc. Fertilizer Injector or Proportioner 2% 1% 0.5%.01% Injector ratios To get from ratios to percent: (1/50) x 100 = 2% To get from percent to ratios : 100/2%=1:50

Parts per million (ppm) One part of a substance into one million parts of another substance 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

Things You Need To Know To Solve ppm Problems: 1.Recommended fertilizer application rate. Example: 8 ounces per 100 gal or 200 ppm nitrogen 2. Fertilizer formulation and analysis. Example: Injection ratio Example: 1:100 4.Size of stock tank in gallons Example: 25 gallons

Weight Basis Example: A chrysanthemum grower gets a recommendation to apply 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 1:30 injection ratio will be used?

Things You Need To Know To Solve This Problem: 1.Recommended fertilizer application rate. 16 ounces per 100 gal 2. Fertilizer formulation and analysis Injection ratio 1:30 4.Size of stock tank in gallons 25 gallons

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 / 25 gal

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 = oz per 25 ratio

Commercial Fertilizer (ppm) Example: A pansy grower gets a recommendation to apply 150 ppm nitrogen using water- soluble formulation. How much fertilizer should be mixed in a 25 gallon stock tank if an injector with a 1:100 injection ratio will be used? How much fertilizer should be mixed in a 25 gallon stock tank if an injector with a 1:100 injection ratio will be used?

Things You Need To Know To Solve This Problem: 1.Recommended fertilizer application rate. 150 ppm nitrogen 2. Fertilizer formulation and analysis Injection ratio 1:100 4.Size of stock tank in gallons 25 gallons

1 oz / 100 gal = 75 ppm The Rule of 75 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 = ppm ( 1 gal = 3.79 L100 gal = 379 L )

Solution Step 1: Convert the ppm recommendation to a weight basis using the following equation: Equation 3 desired ppm = oz fertilizer per 100 gal desired ppm = oz fertilizer per 100 gal % of fertilizer x ppm = 10.0 oz of per 100 gal 20 % x 75(final solution)

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 per 25 gal 100 / 25 gal

Solution Step 3: Use equation 2 to adjust the rate for a 1:100 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 = oz per 25 gal using a 1:100 injection ratio oz per 25 gal using a 1:100 injection ratio

Solution Step 4: Convert ounces to pounds and ounces where: 16 ounces = 1 pound (dry) oz per 25 gal = 15 lbs 10 oz oz/lb (....in a 25 gallon stock tank) 16 oz /lb (....in a 25 gallon stock tank) This will give you 150 ppm with a 1/100 ratio You Are Done !

Equation 4: Oz fertilizer per 100 gal x 0.75 x percent nutrient = Oz fertilizer per 100 gal x 0.75 x percent nutrient = the ppm desired nutrient. the ppm desired nutrient. Not Yet ! How many parts per million of actual phosphorus and potassium will be applied with the 150 ppm N from the ? Phosphorus10.0 oz per 100 gal x 0.75 x 10% P 2 O 5 = 75 ppm P 2 O 5

Not Yet ! For actual phosphorus : P 2 O 5 is actually only 44% elemental phosphorus Therefor 75 ppm P 2 O 5 x 0.44 = 33 ppm actual phosphorus

Equation 4 – Now lets find the potassium true value! Oz fertilizer per 100 gal x 0.75 x percent nutrient = ppm desired nutrient = ppm desired nutrient Potassium 10.0 oz per 100 gal x 0.75 x 20% K 2 O = 150 ppm K 2 O in solution = 150 ppm K 2 O in solution For actual potassium : K 2 O is 83% elemental potassium For actual potassium : K 2 O is 83% elemental potassium 150 ppm K 2 O x 0.83 = ppm actual potassium

Final analysis: 150 ppm N : 33 ppm P : ppm K

A Test ! A poinsettia grower needs to apply 500 ppm nitrogen using ammonium nitrate ( ). 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? How much of each fertilizer must be added to a 5 gallon stock tank for delivery through a 0.4% injector?

If You Got These Answers You Were Right! 15 lbs 9 oz NH 4 NO 3 and 10 lbs 6 oz MgSO 4 15 lbs 9 oz NH 4 NO 3 and 10 lbs 6 oz MgSO 4

Things You Need To Know To Solve This Problem: 1.Recommended fertilizer application rate. 500 ppm nitrogen and 100 ppm magnesium 2. Fertilizer formulation and analysis and 10% magnesium 3.Injection ratio 0.4% 0.4% 4.Size of stock tank in gallons 5 gallons 5 gallons

Solution Step 1: Convert the recommendation for nitrogen ppm to a weight basis : 500ppm = 19.9 oz of per 100 gal (final solution) 500ppm = 19.9 oz of 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 = oz of per 5 gal 100 / 5 gal 100 / 5 gal Step 3: Adjust the rate for a 0.4% injection ratio: 0.4% injection ratio is 1:250 (100/ 0.4 = 250) oz per 5 gal x 250 = oz per 5 gal using 1:250 Step 4: Convert ounces to pounds and ounces: oz per 50 gal = 15 lbs 9 oz per 5 gal for 500 ppm N 16 oz

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) 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 = oz of 10% MgSO 4 per 5 gal 100 / 5 gal 100 / 5 gal Step 7: Adjust the rate for a 0.4% injection ratio: oz per 5 gal x 250 = oz per 5 gal using 1:250 injection ratio Step 8: Convert ounces to pounds and ounces: oz per 50 gal / 16 oz = 10 lbs 6 oz 10% Epsom salts per 5 gal for 100 ppm Mg

Nursery Crops and Fertilizer Recommendations

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 ?

Things You Need To Know To Solve This Problem: 1.Recommended fertilizer application rate. 3 lbs nitrogen per cubic yard 2. Fertilizer formulation and analysis Container size Trade 1 Trade 1 4.Number of containers per cubic yard

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 % 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 % fertilizer

Solution Step 1: Convert the pounds nitrogen recommended to pounds of Nutricote (17-6-8): 3 lbs N/cubic yard x 100 = 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: lbs = lbs Nutricote per Trade 1 container Step 3: Convert pounds to grams and grams to tablespoons: 1 lb = grams 1 tbs = 15 grams lbs x = grams grams / 15 = 1.78 tbs Nutricote Final answer: 2 tbs of Nutricote per Trade 1 Holly per season

Other Useful Conversions Milligrams per liter equal ppm mg/L = ppm 1 gram = 1,000 ppm 1 % = 10,000 ppm

Tank Mixes

Example: A grower wants to prepare a tank mix containing 200 ppm actual nitrogen and 200 ppm actual potassium using calcium nitrate ( ) and potassium nitrate ( ). How much of each fertilizer must be added to a 50 gallon stock tank for delivery through a 1:100 injector? How much of each fertilizer must be added to a 50 gallon stock tank for delivery through a 1:100 injector?

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 ( ) calcium nitrate ( ) potassium nitrate ( ) 3. Elemental nutrient analysis. 4. Injection ratio 1: Size of stock tank in gallons 50 gallons

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.

Solution Start with the potassium nitrate because it contains both nitrogen and potassium. Since K 2 NO 3 contains 13% actual nitrogen and 44% K 2 O, first calculate the amount of K 2 NO 3 to add to 100 gallons to get 200 ppm actual potassium. However, 44% is not actual K, it is K 2 O. Step 1: Convert 44% K 2 O to actual K. Contains 83% actual K : 44 % K 2 O potassium nitrate x 0.83 = 36.52% actual K

Solution Step 2: Determine ounces per 100 gallons of K 2 NO 3 for 200 ppm actual potassium using equation 3: 200 ppm = 7.3 oz of per 100 gal 200 ppm = 7.3 oz of per 100 gal % x 0.75 (final solution)

Solution Step 3: But wait … how much nitrogen was added? Calculate by using equation 4. Calculate by using equation oz per 100 gal x 0.75 x 13% N = ppm actual N So a solution containing 7.3 ounces potassium nitrate per 100 gallons is 200 ppm potassium and ppm nitrogen.

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 per 50 gal 100 / 50 gal Step 5: Using equation 2 to adjust the rate for a 1:100 injection ratio: 3.65 oz per 50 gal x 100 = oz per 50 1:100 injection ratio

Solution Step 6: Convert ounces to pounds and ounces: oz per 50 gal = 22 lbs 13 oz per 50 gal for 200 ppm K 16 oz

Solution Step 7: Calcium nitrate ( ) contains 15.5% nitrogen and 200 ppm total nitrogen is required. However, the potassium nitrate supplied ppm N. Therefore, subtract from 200 and apply equation 3: 200 – ppm = 11.1 oz of 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 per 50 gal 100 / 50 gal

Solution Now You Are Really Done ! Step 10: Convert ounces to pounds and ounces: oz per 50 gal / 16 oz = 34 lbs 11 oz per 50 gal for 200 ppm N Step 9: Using equation 2 to adjust the rate for a 1:100 injection ratio: 5.5 oz per 50 gal x 100 = oz per 50 gal using 1:100 injection ratio