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% 0.1% 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 gallon x injector ratio = oz per stock tank 4.0 oz per 25 gal x 30 = oz per 25 gal tank!

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 Recommended ppm x dilution factor = oz fertilizer/gal stock Recommended ppm x dilution factor = oz fertilizer/gal stock the N number (% ) of fertilizer X 75 the N number (% ) of fertilizer X ppm x 100 = 10.0 oz of per gal stock 20 x 75(final solution)

Solution Step 2: Use equation 1 to adjust for a stock tank size of 25 gallons: (oz per gal stock x (# gallons in stock tank) = Oz fertilizer per stock tank 10.0 oz x 25 gal tank = 250 oz of in the tank

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 Each bag is 25 lbs! Remember 25 lbs x 16 ox…the number of bags needed = 250 oz/ (16 oz X 25lbs ) or 0.62 bags!