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# Conversion Tables, Formulas and Suggested Guidelines for Horticultural Use (B 931)

Prepared by Bodie V. Pennisi, Gary L. Wade, Melvin P. Garber, Paul A. Thomas and James T. Midcap, Horticulture Department
Original manuscript by S.C. Myers and A.J. Lewis, former Extension horticulturists

Pesticide and fertilizer recommendations often are made on a pounds-per-acre or tons-per-acre basis for field production. However, greenhouse and nursery operators, landscape professionals and orchardists often must convert these recommendations to smaller areas, such as row feet or square feet per tree or per pot. Pints, cups, ounces, tablespoons and teaspoons often are the common units of measure. Metric units of measure can further complicate conversion.

This publication is designed to help growers make these calculations and conversions and to provide other data useful in the management, planning and operation of horticultural enterprises. A number of formulas for calculating fertilizer application rates on a parts-per-million basis are given. Tables for fertilizer injector calibration using a conductivity meter, as well as pre-plant application rates for various soil mix components and amendments, also are provided. A brief explanation of how each table is used is provided.

Tables 1 through 3 help determine equivalent measures for liquid (volume) or dry (weight) chemical substances and also converting metric to English units.

 Table 1. Equivalents for liquid measure (volume) Units of Measure Gallons (gal) Quarts (qt) Pints (pt) Fluid Ounces (fl oz) Cups Tablespoons (tbs) Teaspoons (tsp) Milliliters (ml) Cubic Centimeters (cc) Liters (l) 1 4 8 128 16 — — — — — — 1 2 32 4 — — — — — — — 1 16 2 32 — — — — — — — 1 1/8 2 6 30 — — — — — — 1 16 48 240 — — — — — — — 1 3 15 — — — — — — — — 1 5 — — — — — — — — — 1 1 — — — — — — — — 1000 1000 1
 Table 2. Equivalents for dry measure and weight Dry Measure 3 level teaspoonfuls 16 level tablespoonfuls 2 cupfuls 2 pints = = = = 1 level tablespoonful 1 cupful 1 pint 1 quart Weight Pounds/Ounces to Metric 220.46 pounds 100 pounds 2.204 pounds 1.102 pounds 1 pound/16 ounces 8 ounces 4 ounces 3.527 ounces 2 ounces 1 ounce 3/4 ounce 1/2 ounce 1/4 ounce 1/8 ounce 1/16 ounce 1/32 ounce 1/64 ounce 1/128 ounce = = = = = = = = = = = = = = = = = = 100 kilograms (kg) 45.349 kilograms 1 kilogram 500 grams (g) 453.5900 grams 226.78 grams 113.39 grams 110 grams 56.70 grams 28.35 grams 21.25 grams 14.17 grams 7.08 grams 3.54 grams 1.77 grams 885 milligrams 442 milligrams 221 milligrams Ounces to Grams 3/8 1/2 5/8 3/4 7/8 1 2 1/256 1/128 1/64 1/32 1/16 1/8 1/4 = = = = = = = = = = = = = = 10.631 14.75 17.718 21.162 24.805 28.349 56.698 0.111 0.221 0.443 0.886 1.772 3.544 7.087
 Table 3. Metric system conversion table Liquid capacity 1 fluid ounce (fl oz) 1 pint (pt) = 16 fl oz 1 quart (qt) 1 gal (gal) 1 liter (l) 1 milliliter (ml) = = = = = = 30 milliliters (ml) 473 ml 946 ml 3,785 ml 1,000 ml 1 cubic centimeter (cc) Dry material weight 1 ounce (avoirdupois) 1 pound (lb) 1 kilogram (kg) = = = 28.4 grams (g) 453.6 g 1,000 g = 2.2 lb Volume 1 cubic inch (in3) 1 cubic foot (ft3) 1 bushel (bu) 1 cubic yard (yd3) = = = = 16.4 milliliters (ml) 7.48 gal = 28.3 liters (l) 1.24 ft3 = 35.2 liters 21.7 bu = 765 liters Linear 1 inch (in) 1 foot (ft) 1 yard (yd) 1 meter (m) = = = = 2.54 centimeters (cm) 30.48 cm 91.44 cm 100 cm Area 1 square inch (in2) 1 square foot (ft2) 1 square yard (yd2) 1 acre (a) 1 square mile (M2) = = = = = 6.45 square centimeters (cm2) 0.09 square meter (m2) 0.84 square meter (m2) 0.40 hectare (ha) 2.59 square kilometer (km2)

Tables 4 through 7 help determine correct application rates for various pesticides.

 Table 4. Dilution of liquid pesticides at various concentrations Dilution Amount Desired 1 Gal 3 Gal 5 Gal 15 Gal 1:100 2 tbs + 2 tsp 1/2 cup 3/4 cup + 5 tsp 1 cup + 3 tbs 1:200 4 tsp 1/4 cup 6½ tbs 1/2 cup + 2 tbs 1:400 2 tsp 2 tbs 3 tbs 4 tbs + 2½ tsp 1:800 1 tsp 1 tbs 1 tbs + 2 tsp 3 tbs + 2½ tsp 1:1000 3/4 tsp 2¼ tsp 1 tbs + 1 tsp 1 pt + 1/2 cup Example: Directions call for a 1:200 dilution. To prepare 3 gal of finished product, you would need to add 1/4 cup.
 Table 5. Equivalent quantities of dry materials (wettable powders) for various quantities of water based on recommended pounds per 100 gallons Water Recommended Rates 100 gal 1 lb 2 lb 3 lb 4 lb 5 lb 6 lb 50 gal 1/2 lb 1 lb 1½ lb 2 lb 2½ lb 3 lb 25 gal 4 oz 8 oz 12 oz 1 lb 1¼ lb 1½ lb 12.5 gal 2 oz 4 oz 6 oz 8 oz 10 oz 3/4 lb 5 gal 3 tbs 1½ oz 2½ oz 3¼ oz 4 oz 5 oz 1 gal 1 tsp 2 tsp 1 tbs 4 tsp 5 tsp 2 tbs Example: Directions for use specify a rate of 4 lb per 100 gal water. To prepare 1 gal of solution would require 4 tsp of material.
 Table 6. Equivalent quantities of liquid materials (emulsion concentrates, etc.) for various quantities of water based on pints per 100 gallons Water Recommended Rates 100gal 1/2 pt 1 pt 2 pt 3 pt 4 pt 5 pt 50 gal 4 fl oz 8 fl oz 1 pt 1½ pt 2 pt 2½ pt 25 gal 2 fl oz 4 fl oz 8 fl oz 12 fl oz 1 pt 1¼ pt 12.5 gal 1 fl oz 2 fl oz 4 fl oz 6 fl oz 8 fl oz 10 fl oz 5 gal 1 tbs 1 fl oz 2 fl oz 2½ fl oz 3 fl oz 4 fl oz 1 gal 1/2 tsp 1 tsp 2 tsp 3 tsp 4 tsp 5 tsp Example: Directions for use specify a rate of 4 pt per 100 gal water. To prepare 5 gal of solution would require 3 fl oz material.
 Table 7. Rate of application equivalent table Rate per Acre Rate per 1000 sq ft Rate per 100 sq ft Liquid Materials 1 pt 3/4 tbs 1/4 tsp 1 qt 1½ tbs 1/2 tsp 1 gal 6 tbs 2 tsp 25 gal 4⅔ pt 1/2 pt 50 gal 4⅔ qt 1 pt 100 gal 2⅓ gal 1 qt 200 gal 4⅔ gal 2 qt 300 gal 7 gal 3 qt 400 gal 9¼ gal 1 gal 500 gal 11½ gal 1¼ gal Dry Materials 1 lb 2½ tsp 1/4 tsp 3 lb 2¼ tbs 3/4 tsp 4 lb 3 tbs 1 tsp 5 lb 4 tbs 1¼ tsp 10 lb 1/2 cup 2 tsp 100 lb 2⅔ lb 1/4 lb 200 lb 4⅔ lb 1/2 lb 300 lb 7 lb 3/4 lb 400 lb 9¼ lb 1 lb 500 lb 11½ lb 1¼ lb Examples: For liquid materials, 100 gal per acre is equivalent to 2⅓ gal per 1000 ft2 or 1 qt per 100 ft2. For dry materials, 4 lb per acre is equivalent to 3 tbs per 1000 ft2 or 1 tsp per 100 ft2.

Tables 8 through 9 help determine the correct application rates for fertilizers when nutrition recommendations are based on fertilizer weight.

 Table 8. Fertilizer conversions for specified square feet and row area Material grouped by approximate weight per pint Recommended rate per acre* Fertilizer Rate for Specific Areas 100 sq ft 1000 sq ft 10 sq ft 100 sq ft Per 10 feet of row spaced** 1 ft 2 ft 3 ft lb lb lb tbs pt tbs tbs cup 10 oz per pint Sulfur or Dried Blood 100 0.2 2.3 1.2 0.4 1.2 2.4 0.2 500 1.2 11.5 6.0 1.9 6.0 12.0 1.1 1000 2.3 23.0 12.0 3.7 — — — 13 oz per pint Urea or Ammonium Nitrate or Ammonium Chloride 100 0.2 2.3 0.9 0.3 0.9 1.8 0.2 500 1.2 11.5 4.5 1.4 4.5 9.0 0.8 1000 2.3 23.0 9.0 2.8 — — — 16 oz per pint Ammonium Phosphate or Potassium Chloride or Gypsum or Mixed Fertilizers 100 0.2 2.3 0.7 0.2 0.7 1.4 0.1 500 1.2 11.5 3.5 1.2 3.5 7.0 0.7 1000 2.3 23.0 7.0 2.3 — — — 19 oz per pint Calcium Nitrate or Ammonium Sulfate or Superphosphate 100 0.2 2.3 0.6 0.2 0.6 1.2 0.1 500 1.2 11.5 3.0 1.0 3.0 6.0 0.6 1000 2.3 23.0 6.0 2.0 — — — 23 oz per pint Ground limestone or Potassium sulfatex 100 0.2 2.3 0.5 0.2 0.5 1.0 0.1 500 1.2 11.5 2.5 0.8 2.5 5.0 0.5 1000 2.3 23.0 5.0 1.6 — — — 2000 4.6 46.0 10.0 3.2 — — — * Any of the materials listed in the first column can be used at the rates shown below. **High Rates, not desirable in row fertilization, are omitted in the table. Example: You wish to apply calcium nitrate at the rate of 500 lbs per acre. It weighs approximately 19 oz per pt. For application to 100 ft2, you need 1.2 lb or 1.0 pt.
 Table 9. Fertilizer weight as measured by standard pot size Fertilizer Pot Size 2¼" 3" 3½" 4" 5" 6" Ammonium nitrate 2 oz 5½ oz 9 oz 15 oz 1 lb 12 oz 2 lb 15 oz Urea, 45-0-0 2½ oz 6 oz 9 oz 1 lb 1 lb 13 oz 3 lb Superphosphate 2½ oz 6 oz 9½ oz 1 lb 1 lb 14 oz 3 lb 2 oz Dusting sulfur 2½ oz 6 oz 10 oz 1 lb 1 lb 14 oz 3 lb 3 oz Peters, 20-5-30 2½ oz 6 oz 10 oz 1 lb 1 oz 1 lb 15 oz 3 lb 3 oz Ammonium sulfate 3 oz 7 oz 11 oz 1 lb 3 oz 2 lb 3 oz 3 lb 11 oz Osmocote, 14-14-14 3 oz 7½ oz 12 oz 1 lb 4 oz 2 lb 5 oz 3 lb 13 oz MagAmp, 12-62-0 3 oz 7½ oz 12 oz 1 lb 4 oz 2 lb 5 oz 3 lb 14 oz Gypsum, CaSO4 3 oz 8 oz 12½ oz 1 lb 5 oz 2 lb 7 oz 4 lb 1 oz Calcium nitrate 3 oz 8 oz 12½ oz 1 lb 6 oz 2 lb 8 oz 4 lb 2 oz Peters, 15-0-15 3½ oz 8 oz 13 oz 1 lb 6 oz 2 lb 9 oz 4 lb 5 oz Potassium chloride 3½ oz 9 oz 14 oz 1 lb 8 oz 1 lb 12 oz 4 lb 9 oz Sodium nitrate 4 oz 9 oz 15 oz 1 lb 9 oz 2 lb 14 oz 4 lb 13 oz Dolomitic limestone 5½ oz 13 oz 1 lb 5 oz 2 lb 4 oz 4 lb 2 oz 6 lb 14 oz Clay flower pots are frequently used for fertilizer measurement by greenhouse operators. The above shows average weights of several representative fertilizers as measured by standard clay pots when level full. The 3-inch standard is considered to contain 8 fl oz or 1 cup. Since the actual pot size varies with the manufacturer and the volume of a given weight of fertilizer varies with moisture and compaction, deviations of 10 percent may be expected but up to 40 percent may occur.

Tables 10 through 14 help determine the correct application rates for fertilizers with various analysis when nutrition recommendations are based on parts per million and fertilizer injectors are used to deliver liquid plant fertilizer. Table 12 is designed to help growers calibrate their injectors.

 Table 10. Element concentrations for pounds soluble fertilizer in 1000 gal (U.S.) water Desired PPM Pounds of Fertilizer Needed % Nitrogen (N) % Phosphate (P2O5) % Potash (K2O) 30 25 20 15 10 20 15 10 5 25 20 15 10 300 8.3 10.0 12.5 16.7 23.0 — — — — 12.0 15.0 20.0 30.0 275 7.8 9.2 11.4 15.3 23.0 — — — — 11.0 13.7 18.2 27.5 250 7.3 8.4 10.2 13.9 21.8 — — — — 10.0 12.5 16.7 26.2 225 6.2 7.5 9.3 12.5 18.7 — — — — 9.0 11.3 15.0 22.5 200 5.6 6.7 8.4 11.1 16.7 19.2 — — — 8.0 10.0 13.3 20.0 175 4.9 5.8 7.3 9.7 14.6 16.8 22.4 — — 7.0 8.8 10.7 17.5 150 4.2 5.0 6.3 8.3 12.5 14.4 19.2 28.8 — 6.0 7.6 10.0 15.0 125 3.5 4.2 5.3 7.0 10.2 12.0 16.0 24.0 48.0 5.0 6.2 8.4 12.5 100 2.8 3.4 4.2 5.6 8.3 9.6 12.6 19.2 38.4 4.0 5.0 6.7 10.0 75 2.1 2.5 3.1 4.2 6.2 7.2 9.6 14.4 28.8 3.0 3.8 5.0 7.5 50 1.4 1.7 2.1 2.8 4.2 4.8 6.4 9.6 19.2 2.0 2.5 3.4 5.0 25 0.7 0.9 1.1 1.4 2.1 2.4 3.2 4.8 9.6 1.0 1.3 1.7 2.5 Example: You wish to apply 200 ppm N using a 20-10-20 soluble fertilizer. Reading across from 200 ppm under the 20 percent N column, you find 8.4 lb are needed for 1000 gal water. NOTES: 1 oz/2 gal is about 30 lb/1000 gal; 1 oz/3 gal is about 20 lb/1000 gal; 1 oz/5 gal is about 12 lb/1000 gal. 1 oz/gal = 7490 ppm; 1 oz/100 gal = 75 ppm. To determine Parts Per Million (ppm) of an element in a fertilizer, simply multiply the percent of that element by 75. The answer will be the ppm of the element per oz of the fertilizer in 100 gal of water. As an example, Ammonium Sulfate contains approximately 20 percent Nitrogen. 20 percent multiplied by 75 is 15, which is the ppm of Nitrogen in 1 oz of Ammonium Sulfate per 100 gal of water.
 Table 11. Injection ratios and nitrogen concentrations for constant fertilization1 Ratio Ounces of Fertilizer per Gal Concentrate 100 ppm N 150 ppm N 200 ppm N 30% N formulaa 1:200 13.5 20.2 27.0 1:200 9.0 13.5 18.0 1:150 6.7 10.1 13.5 1:128 5.7 8.6 11.5 1:100 4.5 6.7 9.0 1:50 2.2 3.3 4.5 1:30 13.0 2.0 2.7 1:24 1.0 1.6 2.1 1:15 0.67 1.0 1.3 25% N formulab 1:300 16.5 24.7 33.0 1:200 11.0 16.5 22.0 1:150 8.2 12.3 16.5 1:128 7.0 10.5 14.0 1:100 5.5 8.2 11.0 1:50 2.7 4.1 5.5 1:30 1.6 2.4 3.3 1:24 1.3 1.9 2.6 1:15 0.82 1.2 1.6 20% N formulac 1:300 20.2 30.3 40.5 1:200 13.5 20.2 27.0 1:150 10.1 15.1 20.2 1:128 8.6 12.9 17.2 1:100 6.7 10.1 13.5 1:50 3.3 5.0 6.7 1:30 2.0 3.0 4.0 1:24 1.6 2.4 3.2 1:15 1.0 1.5 2.0 15% N formulad 1:300 27.0 40.5 54.0 1:200 18.0 27.0 36.0 1:150 13.5 20.2 27.0 1:128 11.5 17.2 23.0 1:100 9.0 13.5 18.0 1:50 4.5 6.7 9.0 1:30 2.7 4.0 5.4 1:24 2.1 3.2 4.3 1:15 1.3 2.0 2.7 1From Ball RedBook, 16th Edition, published by Ball Publishing. Reprinted with permissionae.g, 30-10-10 be.g., 25-5-20, 25-10-10, 25-0-25 ce.g., 20-20-20, 20-5-30, 21-7-7 de.g., 15-15-15, 15-30-15, 16-4-12
 Table 12. Injector calibration with a conductivity meter1 A. Peters Single Element Fertilizer Components ppm Nitrogen Ammonium Nitrate NH4NO3 34% N Ammonium Sulfate (NH4)2SO4 21% N Sodium Nitrate NaNO3 16% N Potassium Nitrate KNO3 14% N Calcium Nitrate Ca(NO3)2 15.5% N Epsom Salt MgSO4 10% Mg 50 0.23 0.45 0.43 0.48 0.37 0.38 75 0.35 0.68 0.65 0.71 0.55 0.56 100 0.46 0.90 0.86 0.95 0.74 0.75 125 0.58 1.13 1.08 1.18 0.92 0.94 150 0.69 1.35 1.29 1.42 1.11 1.13 175 0.81 1.58 1.51 1.66 1.30 1.31 200 0.92 1.90 1.72 1.90 1.48 1.50 225 1.04 2.03 1.94 2.14 1.66 1.69 250 1.15 2.25 2.15 2.37 1.85 1.88 275 1.27 2.48 2.37 2.61 2.04 2.06 300 1.38 2.70 2.58 2.85 2.22 2.25 350 1.61 3.15 3.01 3.32 2.59 2.63 400 1.84 3.60 3.44 3.80 2.96 3.00 450 2.07 4.05 3.87 4.27 3.33 3.38 500 2.30 4.50 4.30 4.75 3.70 3.75 550 2.53 4.95 4.73 5.22 4.07 4.13 600 2.76 5.40 5.16 5.70 4.44 4.50 650 2.99 5.85 5.59 6.17 4.81 4.88 700 3.22 6.30 6.02 6.65 5.18 5.25 750 3.45 6.75 6.45 7.12 5.50 5.63 800 3.68 7.20 6.88 7.60 5.92 6.00 850 3.91 7.65 7.31 8.07 6.29 6.38 900 4.14 8.10 7.74 8.55 6.66 6.75 950 4.37 8.55 8.17 9.02 7.03 7.13 1000 4.60 9.00 8.60 9.50 7.40 7.50 1Adapted from Grace Horticultural Products. W.1 R. Grace & Co. Cambridge, Massachusetts 02140. NOTES: 1) For use with meters in millimhos with Peters® Single Element Fertilizer Components. 2) These are readings made with distilled water. 3) Test your plain irrigation water first and subtract that reading from the fertilizer-injected water. For example, your water test indicates 0.5 mmhos and you are applying 500 ppm N with calcium nitrate. Your calibration reading is 3.70 - 0.5 = 3.20 mmhos.
 Table 12. Injector calibration with a conductivity meter1 B. Peters Mixed Soluble Fertilizer Analysis ppm Nitrogen 20-20-20 20-19-18 20-10-15 20-5-30 25-5-20 25-10-10 30-10-10 5-11-26 Hydrosol 15-16-17 15-11-29 15-20-25 50 0.23 0.31 0.22 0.12 0.09 1.00 0.32 75 0.34 0.47 0.33 0.18 0.14 1.50 0.48 100 0.45 0.62 0.44 0.24 0.18 2.00 0.65 125 0.56 0.78 0.56 0.30 0.23 2.50 0.82 150 0.68 0.93 0.69 0.36 0.27 3.00 1.00 175 0.79 1.09 0.81 0.43 0.32 3.50 1.20 200 0.90 1.24 0.94 0.51 0.36 4.00 1.40 225 1.01 1.40 1.07 0.57 0.41 4.50 1.56 250 1.13 1.55 1.20 0.62 0.47 5.00 1.72 275 1.24 1.71 1.32 0.71 0.51 5.50 1.91 300 1.35 1.86 1.43 0.80 0.54 6.00 2.10 350 1.58 2.17 1.66 0.92 0.64 6.50 2.45 400 1.80 2.48 1.90 1.04 0.74 7.00 2.80 450 2.03 2.79 2.15 1.18 0.85 7.50 3.15 500 2.25 3.10 2.40 1.32 0.96 8.00 3.50 550 2.48 3.41 2.61 1.45 1.06 - 3.84 600 2.70 3.72 2.82 1.58 1.16 - 4.18 650 2.93 4.03 3.03 1.71 1.26 - 4.52 700 3.15 4.34 3.24 1.84 1.36 - 4.80 750 3.38 4.65 3.45 1.98 1.46 - 5.20 800 3.60 4.96 3.66 2.11 1.56 - 5.54 850 3.83 5.27 3.87 2.24 1.66 - 5.88 900 4.05 5.58 4.08 2.37 1.76 - 6.22 950 4.28 5.89 4.29 2.50 1.86 - 6.56 1000 4.50 6.20 4.5 2.63 1.96 - 6.90 1Adapted from Grace Horticultural Products. W.1 R. Grace & Co. Cambridge, Massachusetts 02140. NOTES: 1) For use with meters in millimhos with Peters® Fertilizer formulations. 2) These readings are made with distilled water. 3) Test your plain irrigation water first and subtract that reading from the fertilizer-injected water. For example, your water test indicates 0.2 mmhos and you are applying 200 ppm N with 15-15-15 fertilizer. Your calibration reading is 1.30 - 0.2 = 1.10 mmhos.
 Table 12. Injector calibration with a conductivity meter1 B. Peters Mixed Soluble Fertilizer Analysis (cont.) ppm Nitrogen 15-15-15 15-10-30 15-30-15 15-0-15 16-4-12 21-7-7 Acid 21-7-7 Neutral 50 0.30 0.32 0.31 0.36 0.32 0.28 0.21 75 0.46 0.51 0.47 0.55 0.48 0.42 0.32 100 0.62 0.70 0.62 0.74 0.64 0.56 0.42 125 0.79 0.87 0.78 0.94 0.81 0.70 0.53 150 0.96 1.50 0.93 1.15 0.98 0.84 0.63 175 1.13 1.23 1.09 1.35 1.14 0.98 0.74 200 1.30 1.41 1.24 1.55 1.31 1.12 0.84 225 1.47 1.59 1.40 1.72 1.47 1.26 0.95 250 1.65 1.78 1.55 1.90 1.62 1.40 1.05 275 1.82 1.95 1.71 2.09 1.81 1.54 1.16 300 1.98 2.12 1.86 2.28 2.00 1.68 1.26 350 2.31 2.45 2.17 2.64 2.29 1.96 1.47 400 2.65 2.78 2.48 3.00 2.58 2.24 1.68 450 2.98 3.12 2.79 3.34 2.93 2.52 1.89 500 3.25 3.46 3.10 3.68 3.28 2.80 2.10 550 3.55 3.76 3.41 3.98 3.57 3.08 2.31 600 3.85 4.06 3.72 4.28 3.86 3.36 2.52 650 4.15 4.36 4.03 4.58 4.15 3.64 2.73 700 4.45 4.66 4.34 4.88 4.44 3.92 2.94 750 4.75 4.95 4.65 5.20 4.72 4.20 3.15 800 5.05 5.25 4.96 5.50 4.98 4.48 3.36 850 5.35 5.55 5.27 5.80 5.24 4.76 3.57 900 5.65 5.85 5.58 6.10 5.50 5.04 3.78 950 5.95 6.15 5.89 6.40 5.76 5.32 3.99 1000 6.25 6.45 6.20 6.70 6.00 5.60 4.20 1Adapted from Grace Horticultural Products. W.1 R. Grace & Co. Cambridge, Massachusetts 02140. NOTES: 1) For use with meters in millimhos with Peters® Fertilizer formulations. 2) These readings are made with distilled water. 3) Test your plain irrigation water first and subtract that reading from the fertilizer-injected water. For example, your water test indicates 0.2 mmhos and you are applying 200 ppm N with 15-15-15 fertilizer. Your calibration reading is 1.30 - 0.2 = 1.10 mmhos.
 Table 13A. Parts per million of desired nutrient to ounces of fertilizer carrier in 100 gallons of water and vice versa1 Ounces of Fertilizer Carrier in 100 Gallons Percentage of Desired Nutrient in Fertilizer Carrier 12 13 14 15.5 16 20 20.5 21 1 9 9.7 10.5 11.6 12.0 15.0 15.3 15.7 2 18 19.5 21.0 23.2 24.0 29.9 30.7 31.4 3 27 29.3 31.4 35.0 35.9 44.9 46.0 47.2 4 36 38.9 41.9 46.4 47.9 59.9 61.4 62.9 6 54 58.4 62.9 70.0 71.9 89.9 92.1 94.3 8 72 77.8 83.8 92.8 95.8 119.7 122.7 125.7 16 144 155.7 167.7 185.6 191.7 239.5 245.5 251.5 24 216 233.5 251.5 278.4 287.5 359.2 368.2 377.2 32 288 311.4 335.4 371.3 383.4 479.0 490.9 502.9 40 359 389.2 419.2 464.0 479.2 598.7 613.7 628.6 48 431 467.0 503.0 556.8 575.0 718.5 736.4 754.4 56 503 544.7 586.9 649.7 670.9 838.2 859.2 880.1 64 575 622.7 670.7 742.4 766.7 958.0 981.9 1005.8 1From Nelson, P.V. 1998. Greenhouse Operations and Management, 5th ed. Published by Prentice Hall, Inc. Reprinted with permission.
 Table 13A. Parts per million of desired nutrient to ounces of fertilizer carrier in 100 gallons of water and vice versa1 (cont) Ounces of Fertilizer Carrier in 100 Gallons Percentage of Desired Nutrient in Fertilizer Carrier 33 44 45 53 60 62 1 24.7 32.9 33.7 39.7 44.9 46.4 2 49.4 65.9 67.4 79.3 89.8 92.0 3 74.1 98.8 101.0 117.0 134.7 139.2 4 98.8 131.7 134.7 158.7 179.6 185.6 6 148.2 197.6 202.1 238.0 269.4 278.4 8 197.6 263.4 269.4 317.3 359.2 371.2 16 395.2 526.9 538.9 634.6 718.5 742.4 24 592.7 790.3 808.3 952.0 1077.7 1113.6 32 790.3 1053.7 1077.7 1269.3 1436.9 1484.8 40 987.9 1317.2 1347.1 1586.6 1796.2 1856.1 48 1185.5 1580.6 1616.5 1903.9 2155.4 2227.2 56 1383.0 1844.0 1886.0 2221.2 2514.6 2598.4 64 1580.6 2107.5 2155.4 2538.6 2873.9 2969.7 1From Nelson, P.V. 1998. Greenhouse Operations and Management, 5th ed. Published by Prentice Hall, Inc. Reprinted with permission.
 Table 13B. Parts per million of desired nutrient to ounces of fertilizer carrier in 100 gallons of water and vice versa1 Grams of Fertilizer Carrier in 1 Liter PPM of Desired Nutrient in Fertilizer Carrier 0.1 12 13 14 16 16 20 20.5 21 0.2 24 26 28 31 3 40 41.0 42 0.3 36 39 42 47 48 60 61.5 63 0.4 48 52 56 62 64 80 82.0 84 0.6 72 78 84 93 96 120 123.0 126 0.8 96 104 112 124 128 160 164.0 168 1.0 120 130 140 155 160 200 205.0 210 1.5 180 195 210 233 240 300 307.0 315 2.0 240 260 280 310 320 400 410.0 420 2.5 300 325 350 388 400 500 512.5 525 3.0 360 390 420 465 480 600 615.0 630 3.5 420 455 490 543 560 700 717.5 735 4.0 480 520 560 620 640 800 820.0 840 1From Nelson, P.V. 1998. Greenhouse Operations and Management, 5th ed. Published by Prentice Hall, Inc. Reprinted with permission.
 Table 13B. Parts per million of desired nutrient to grams of fertilizer carrier in 1 liter water and vice versa1 (cont) Grams of Fertilizer Carrier in 1 Liter PPM of Desired Nutrient in Fertilizer Carrier 0.1 33 44 45 53 60 62 0.2 66 88 90 106 120 124 0.3 99 132 135 159 180 186 0.4 132 176 180 212 240 248 0.6 198 264 270 318 360 372 0.8 264 352 360 424 480 496 1.0 330 440 450 530 600 620 1.5 495 660 675 795 900 930 2.0 660 880 900 1060 1200 1240 2.5 825 1100 1125 1325 1500 1550 3.0 990 1320 1350 1590 1800 1860 3.5 1155 1540 1575 1855 2100 2170 4.0 1320 1760 1800 2120 2400 2480 1From Nelson, P.V. 1998. Greenhouse Operations and Management, 5th ed. Published by Prentice Hall, Inc. Reprinted with permission.
 Table 14. Conversion factors among electrical conductivity (EC) units1 From To Multiply by: mmhos/cm or mS/cm or dS/cm mhos x 10-5/cm 100 mhos x 10-5/cm mmhos/cm or mS/cm or dS/cm 0.01 mmhos/cm or mS/cm or dS/cm ∝mhos or mhos x 10-6 1000 ∝mhos or mhos x 10-6 mmhos/cm or mS/cm or dS/cm 0.001 mmhos/cm or mS/cm or dS/cm ppm 6702 ppm mmhos/cm or mS/cm or dS/cm 0.00149252 mhos x 10-5/cm ppm 6.702 ppm mhos x 10-5/cm 0.149252 ∝mhos or mhos x 10-6 ppm 0.67022 ppm ∝mhos or mhos x 10-6 1.49252 1 Adapted from T.J. Cavins, et al., 2000. 2 Some labs report EC in terms of ppm or convert EC to ppm. Although 670 is the basis used in this example, the conversion factor can vary between 640 and 700. This conversion factor is an average due to the variability in the type of fertilizer salts that contribute to the substrate EC in each sample, and it should be considered a broad approximation. Expressing EC in terms of mS/cm or mhos/cm is the preferred method.

Table 15 is designed to help growers decide which acid to add and in what quantities to acidify their irrigation water.

 Table 15. Various acids to add to irrigation water for acidification1 Note: The table is an example from software called Alkalinity Calculator, available at www.ces.ncsu.edu/depts/hort/floriculture/software/alk.html. It is an acidification analysis done on a water sample with a starting pH of 8.0 and alkalinity of 200 ppm CaCO3 acidified to an end point pH of 5.8. For your specific water sample, download the Alkalinity Calculator and follow the directions listed on the website. You will need to obtain a water report on your irrigation water prior to running the software. You will need to know the water pH and alkalinity of your sample and have an idea about what end-point pH you want to obtain after acidification. The software also gives you information about the cost of the acidification treatment. ALTERNATIVE ACIDS TO ADD TO IRRIGATION WATER Amounts Acids Phosphoric Acid (75%) Phosphoric Acid (85%) Sulfuric Acid (35%) Sulfuric Acid (93%) Nitric Acid (61.4%) Nitric Acid (67%) For Small Volumes ml per liter 0.253 0.207 0.348 0.087 0.234 0.209 fl oz per gallon 0.032 0.027 0.044 0.011 0.030 0.027 ml per gallon 0.956 0.785 1.316 0.330 0.884 0.793 For a 1:100 Injector fl oz per gallon (conc.) 3.23 2.65 4.45 1.12 2.99 2.68 ml per gallon (conc.) 95.63 78.47 131.59 32.98 88.40 79.28 For a 1:128 Injector fl oz per gallon (conc.) 4.14 3.40 5.70 1.43 3.83 3.43 ml per gallon (conc.) 122.41 100.44 168.44 42.22 113.16 101.48 For a 1:200 Injector fl oz per gallon (conc.) 6.47 5.31 8.90 2.23 5.98 5.36 ml per gallon (conc.) 191.27 156.94 263.19 65.97 176.81 158.56 NUTRIENTS ADDED BY EACH TYPE OF ACID Nutrients Added Phosphorus Phosphorus Sulfur Sulfur Nitrogen Nitrogen Amount Added (ppm) 94.6 94.6 50.3 50.3 43.7 43.7 Use the information above for modifying your fertility program.

Tables 16 through 20 help determine which fertilizers to use based on chemical analysis, reaction in substrate, longevity in substrate (slow release fertilizers), and incorporation rates for some popular slow release fertilizers. Tables 17 and 18 are specifically designed to provide detailed information on fertilizer calculations, which also aid determine correct application rates.

 Table 16. Amounts of nutrient sources to combine in making various fertilizer formulas1 Fertilizer Name Nutrient Sources2 Analysis 33 -0 -0 13 -0 -44 15.5 -0 -0 16 -0 -0 21 -0 -0 45 -0 -0 0 -0 -60 12 -62 -0 21 -53 -0 % of N as NH4 + Urea Reaction in Substrate4 Ammonium nitrate 33-0-0 X 50 A Potassium nitrate 13-0-44 X 0 N Calcium nitrate 15.5-0-0 X 6 B Sodium nitrate 16-0-0 X 0 B Ammonium sulfate 21-0-0 X 100 A Urea 45-0-0 X 100 SA Potassium chloride 0-0-60 X - N Monoammonium phosphate 12-62-0 X 100 A Diammonium phosphate3 21-53-0 X 100 SA Magnesium nitrate 10-0-0 0 B Chrysanthemum green 18-0-22 1 2 1 47 A General Summer 20-10-24 1 1 2 1 83 A General low phosphate 21-4-20 7 4 1 55 A General summer 21-17-20 1 2 3 3 90 A General 17-6-27 4 4 1 57 A UConn Mix 19-5-24 6 2 2 1 49 N Editor's favorite 20-5-30 13 4 2 57 SA 20-20-20 substitute 20-20-22 4 1 3 67 SA Starter and pink hydrangea 12-41-15 1 2 65 SA Starter and pink hydrangea 17-35-16 1 4 10 100 SA N-K only 16-0-24 2 1 2 40 SA N-K only 20-0-30 1 2 28 SA Blue hydrangea 13-0-22 2 1 100 VA Blue hydrangea 15-0-15 3 1 100 VA Acid 21-9-9 3 1 7 1 2 79 VA Spring carnation 10-0-17 5 2 0 B Winter nitrate 15-0-15 1 2 5 B Winter potash 15-0-22 1 1 4 B Lily substitute 16-4-12 1 4 6 1 22 N High K 15-10-30 7 1 2 28 N 1From Nelson, P.V. 1998. Greenhouse Operations and Management, 5th ed. Published by Prentice Hall, Inc. Reprinted with permission. 2For names of nutrient sources, see the first nine entries in the Name column. 3Diammonium phosphate may be pelletized and coated. To dissolve, use very hot water and stir vigorously. Sediment formation should not cause concern. Use crystalline potassium chloride if possible. 4B = basic; N = neutral; SA = slightly acid; A = acid; VA = very acid. NOTE: For example, an 18-0-22 formula fertilizer can be formulated by blending together 1 lb of ammonium nitrate plus 2 lbs of potassium nitrate plus 1 lb of ammonium sulfate. This formulation is determined by locating the 18-0-22 formula in the Analysis column. Then the three numbers 1, 2 and 1 are located in the row after this formula. Each of the three numbers is traced to the X above it and then to the nutrient source to the left of the X.
 Table 17. Formulas for additional fertilizer calculations Compound Formula Weight Ammonium Nitrate Ammonium SulfateCalcium Nitrate Potassium NitratePotassium Chloride Potassium SulfateUrea NH4NO3 (NH4)2SO4 Ca(NO3)2 KNO3 KCl K2SO4 CO(NH2)2 80.8132.0 164.0 101.1 74.6 174.2 60.0 Element Symbol Atomic Weight Calcium Carbon Chlorine Hydrogen Nitrogen Oxygen Phosphorus Potassium Ca C Cl H N O P k 40.1 12.0 35.5 1.0 14.0 16.0 31.0 39.1

Using Chemicals

1)

 mg of fertilizer source/liter of water = (ppm)(formula weight) (atomic weight of element)(number of units in formula of fertilizer source)

2)

 ppm = (mg of fertilizer/liter of water)(atomic weight of element)(number of units of element in formula of fertilizer source) (formula weight of fertilizer source)

3) to convert mg/l to lbs/100 gal, multiply mg by 0.0008344

4) to convert lbs/100 gal to mg/l, divide lbs by 0.0008344

EXAMPLE: How many pounds of potassium sulfate (K2SO4) need to be dissolved in 100 gallons of water to make 100 ppm K solution. Get the formula weight of potassium sulfate (K2SO4) and the atomic weight of potassium from Table 14. Then:
1) mg of K2SO4 / liter of water = (100 x 174.2) Ã· (39.1 x 2) = 222.8 mg/L
2) 222.8 mg/L x 0.00083440 = 0.186 lbs potassium sulfate/100 gal

Using Premixed Fertilizers

1)

 mg of mixed fertilizer/liter of water = (ppm of N desired)(100) (% N in fertilizer)

2)

 ppm of P = (mg of mixed fertilizer/liter of water)(% P2O5)(0.4366) 100

3)

 ppm of K = (mg of mixed fertilizer/liter of water) (% K2O) (0.8301) 100

4)

 mg of mixed fertilizer/liter of water = (ppm of P desired)(100) (% P2O5)(0.4366)

5)

 mg of mixed fertilizer/liter of water = (ppm of k desired)(100) (% K2O) (0.8301)

6)

 mg of mixed fertilizer/liter of water = (mg of mixed fertilizer/liter of water)(% N) 10
 Table 18. Miscellaneous conversions used in fertilizer calculations 1 millimeter or cubic centimeter of water weighs 1 gram 1 liter of water weighs 1 kilogram 1 gallon of water weighs 8.34 pounds 1 part per million (ppm) 1 part per million 1 part per million = 0.0001 percent = 1 milligram/liter =0.013 ounces in 100 gallons of water 1 percent 1 percent 1 percent 1 percent 1 percent = 10,000 ppm = 10 grams per liter = 10,000 grams per kilogram = 1.33 ounces by weight per gallon of water = 8.34 pounds per 100 gallons of water 0.1 percent 0.01 percent 0.001 percent 0.0001 percent = 1000 ppm = 100 ppm = 100 ppm = 100 ppm = 1000 milligrams per liter = 100 milligrams per liter = 10 milligrams per liter = 1 milligram per liter Approximate weight-volume measurements for making small volumes of water soluble fertilizers 1 cup = 8 oz or 0.5 lbs of fertilizer 2 cups = 1 lb of fertilizer 1 tablespoon = 0.5 oz of fertilizer 2 tablespoons = 1 oz of fertilizer Useful conversions 1 ton/acre = 20.8 grams/square foot 1 ton/acre = 1 lb/21.78 square feet 1 gram/square foot = 96 lbs/acre 1 lb/acre = 0.0104 g/square foot 100 lbs/acre = 0.2296 lbs/100 square feet grams/square foot x 96 = lbs/acre lbs/square foot x 43,560 = lbs/acre 100 square feet = 1/435.6 or 0.002296 acres Weight conversions from lbs/acre to weight/100 square feet lbs/acre amount applied/100 square feet 100 3.7 oz 200 7.4 oz 300 11.1 oz 400 14.8 oz 500 1 lb 2.5 oz 600 1 lb 6 oz 700 1 lb 10 oz 800 1 lb 13 oz 900 2 lb 1 oz 1000 2 lb 5 oz 2000 4 lb 10 oz Percent to Ratio Conversion 2.0% 1:50 1.5% 1:67 1.0% 1:100 0.9% 1:111 0.8% 1:128 0.7% 1:143 0.6% 1:167 0.5% 1:200 0.4% 1:250 0.3% 1:333 0.2% 1:500
 Table19. Osmocote® controlled-release fertilizers and their release periods1 Analysis Longevity2 (months) Product Name 14-14-14 3-4 Osmocote®3 19-6-12 3-4 Osmocote®3 13-13-13 8-9 Osmocote®3 18-6-12 8-9 Osmocote®3 Fast Start 18-6-12 8-9 Osmocote®3 17-7-12 12-14 Osmocote®3 15-9-12 3-4 Osmocote® Plus 15-9-12 5-6 Osmocote® Plus 15-9-12 8-9 Osmocote® Plus 15-9-12 12-14 Osmocote® Plus 15-9-12 14-16 Osmocote® Plus 16-8-12 8-9 Osmocote® Plus Minors Tablets 19-5-8 + Minors 8-9 Osmocote® Pro with Poly-S 19-5-9 + Minors 12-14 Osmocote® Pro with Poly-S 20-5-8 + Minors 8-9 Osmocote® Pro with Poly-S 24-4-8 8-9 Osmocote® Pro with Resin Coated Urea 24-4-7 12-14 Osmocote® Pro with Resin Coated Urea 24-4-6 14-16 Osmocote® Pro with Resin Coated Urea 21-4-7 w/ Mg & Fe 8-9 Osmocote® Pro with Resin Coated Urea 21-3-7 w/ Mg & Fe 12-14 Osmocote® Pro with Resin Coated Urea 22-4-9 + Minors 5-6 Osmocote® Pro with Resin Coated Urea 22-4-8 + Minors 8-9 Osmocote® Pro with Resin Coated Urea 22-4-7 + Minors 12-14 Osmocote® Pro with Resin Coated Urea 22-4-6 + Minors 14-16 Osmocote® Pro with Resin Coated Urea 20-4-9 8-9 Osmocote® Pro with Methylene Urea and Ureaform 20-4-8 12-14 Osmocote® Pro with Methylene Urea and Ureaform 23-4-8 + Minors 14-16 Osmocote® Pro + ScottKote™ 19-7-10 + Fe 3-4 Osmocote® Pro with Uncoated NPK and Iron 18-7-10 + Fe 8-9 Osmocote® Pro with Uncoated NPK and Iron 17-7-10 + Fe 12-14 Osmocote® Pro with Uncoated NPK and Iron 13-10-13 5-6 Osmocote® Pro with IBDU and Minors 15-10-10 8-9 Osmocote® Pro with IBDU and Minors 18-8-8 8-9 Osmocote® Pro with IBDU and Minors 20-4-8 8-9 Osmocote® Pro with IBDU and Minors 18-5-9 12-14 Osmocote® Pro with IBDU and Minors 17-6-12 + Minors 3-4 Sierra® Tablets 17-6-10 + Minors 8-9 Sierra® Tablets 1 From the Scotts Company and Subsidiaries, Marysville, OH 43041. 2 At an average root substrate temperature of 70 degrees F (21 degrees C). 3 Six trace elements plus magnesium.
 Table 20. Rates in lb/yd3 (kg/m3) for incorporation of three of the most popular formulations of Nutricote into greenhouse root substrates1 Release Type (days3) Sensitive Crops Medium-Feeding Crops Heavy-Feeding Crops 13-13-13 70 2.5 (1.5) 5 (3.0) 8.5 (5.1) 100 3.5 (2.1) 140 5 (3.0) 9 (5.4) 13 (7.8) 180 6 (3.6) 11 (6.6) 17 (10.2) 270 8 (4.8) 13 (7.8) 21 (12.6) 360 11 (6.6) 15 (9.0) 25 (15.0) 14-14-14 40 2 (1.2) 5 (3.0) 8 (4.7) 70 4 (2.4) 9 (5.4) 14 (8.3) 100 5 (3.0) 12 (7.1) 20 (11.9) 140 8 (4.7) 15 (9.0) 22 (13.0) 180 12 (7.1) 20 (11.9) 28 (16.6) 270 16 (9.5) 24 (14.2) 32 (19.0) 360 20 (11.9) 28 (16.6) 36 (21.3) 18-6-8 70 2 (1.2) 4.5 (2.7) 7.5 (4.5) 100 3 (1.8) 6.5 (3.9) 11 (6.6) 140 4.5 (2.7) 8 (4.8) 12 (7.2) 180 6 (3.6) 11 (6.6) 14 (8.4) 270 8 (4.8) 13 (7.8) 16 (12.0) 360 11 (6.6) 15 (9.0) 18 (13.8) 1 From Nelson, P.V. 1998. Greenhouse Operations and Management, 5th Â ed. Published by Prentice Hall, Inc. Reprinted with permission.

Tables 21 through 22 are designed to assist growers in correcting the pH of the growing substrate.

 Table 21. Materials and rates necessary to lower the pH level of greenhouse potting substrate 0.5 to 1.0 units1 Material Pounds to incorporate in lbs/yd3 Pounds to dissolve in 100 gal water2 Rate of change in pH Aluminum sulfate 1.5 6.0 Rapid Iron sulfate 1.5 6.0 Moderate Finely ground elemental sulfur 0.75 - Slow 1 Adapted from Bailey, D.A. 1996.2 Apply this drench as a normal watering, about 1 quart per square foot or 8 fluid ounces per 6-inch pot.
 Table 22. Approximate amount of materials required to change pH of peat-based potting mixes1 Beginning pH Pounds per cubic yard to change acidity to pH 5.7 for: 50% Peat 50% Moss 100% Peat 7.52 2.0 3.4 7.0 1.5 2.5 6.5 1.0 2.0 5.03 2.5 3.5 4.5 5.6 7.4 4.0 7.9 11.5* 3.5 10.5* 15.58 1 Adapted from Conover, C.A., and R.T. Poole. 1984.2 Add sulfur or acidifying mixture to lower pH to 5.7. 3 Add dolomitic lime or equivalent amount of calcium to raise pH to 5.7.* Addition of more than 10 pounds of dolomitic per yd3 can cause micro-nutrient deficiencies.

Table 23 will help when applying various plant growth regulators.

 Table 23A. Dilution/conversion chart for A-REST (0.0264% active ingredient)1 Spray Spray Solution (ppm) Fluid Ounces per Gallon of Final Solution Milliliters per Gallon of Final Solution Milliliters per Liter of Final Solution 1 48 14.34 3.79 3 1.45 43.02 11.36 10 4.85 143.39 37.88 25 12.12 358.47 94.70 50 24.24 716.93 189.39 75 36.36 1075.40 284.09 100 48.48 1433.87 378.79 Drench Dose (Milligrams per 6-in Pot) Drench Volume per 6-in Pot* (Fluid Ounces) ppm solution Fluid Ounces per Gallon of Final Solution Milliliters per Gallon of Final Solution Milliliters per Liter of Final Solution 0.125 4 1.06 0.51 15.15 4.0 0.25 4 2.11 1.02 30.30 8.01 0.50 4 4.23 2.05 60.61 16.01 0.75 4 6.34 3.07 90.91 24.02 1.00 4 8.45 4.10 121.21 32.02 1Adapted from Hammer, P.A. 1992. *2 fl oz/4-in pot; 3 fl oz/5-in pot; 10 fl oz/8-in pot
 Table 23B. Dilution/conversion chart for CYCOCEL (11.8% active ingredient)1 Spray Spray Solution (ppm) Fluid Ounces per Gallon of Final Solution Milliliters per Gallon of Final Solution Milliliters per Liter of Final Solution 1,000 1.08 32.08 8.47 1,500A 1.63 48.12 12.71 2,000 2.17 64.16 16.95 2,500 2.71 80.20 21.19 3,000B 3.25 96.24 25.42 5,000 5.42 160.40 42.37 Drench Dose (Milligrams per 6-in Pot) Drench Volume per 6-in Pot* (Fluid Ounces) ppm solution Fluid Ounces per Gallon of Final Solution Milliliters per Gallon of Final Solution Milliliters per Liter of Final Solution 355 6 2,000 2.17 64.18 16.95 532 6 3,000B 3.25 96.18 25.42 710 6 4,000 4.34 128.36 33.90 1Adapted from Hammer, P.A. 1992.ACommonly referred to as 1:80. BCommonly referred to as 1:40. *2 fl oz/2.25- to 3-in pot; 3 fl oz/4-in pot; 4 fl oz/5-in pot; 8 fl oz/8-in pot.
 Table 23C. Dilution/conversion chart for B-NINE WSG (85% active ingredient)1 Spray Spray Solution (ppm) Ounces per Gallon of Final Solution Grams per Gallon of Final Solution Grams per Liter of Final Solution 1,000 0.16 4.45 1.18 2,500 0.39 11.13 2.94 5,000 0.79 22.26 5.88 7,500 1.18 33.40 8.82 1Adapted from Hammer, P.A. 1992.
 Table 23D. Dilution/conversion chart for BONZI (0.4% active ingredient)1 Spray Spray Solution (ppm) Fluid Ounces per Gallon of Final Solution Milliliters per Gallon of Final Solution Milliliters per Liter of Final Solution 1 0.032 0.95 0.25 3 0.096 2.84 0.75 5 0.160 4.73 1.25 10 0.320 9.46 2.50 15 0.480 14.20 3.75 25 0.800 23.66 6.25 45 1.440 42.59 11.25 60 1.920 56.78 15.00 90 2.880 85.17 22.50 Drench Dose (Milligrams per 6-in Pot) Drench Volume per 6-in Pot* (Fluid Ounces) ppm Fluid Ounces per Gallon of Final Solution Milliliters per Gallon of Final Solution Milliliters per Liter of Final Solution 0.1 4 0.85 0.03 0.8 0.21 0.2 4 1.69 0.05 1.6 0.42 0.5 4 4.23 0.14 4.0 1.06 1.0 4 8.45 0.27 8.0 2.11 1.9 4 16.06 0.51 15.2 4.02 1Adapted from Hammer, P.A. 1992. * 2 fl oz/4-in pot; 3 fl oz/5-in pot; 10 fl oz/8-in pot.
 Table 23E. Dilution/conversion chart for SUMAGIC (0.055% active ingredient)1 Spray Spray Solution (ppm) Fluid Ounces per Gallon of Final Solution Milliliters per Gallon of Final Solution Milliliters per Liter of Final Solution 1 0.26 7.57 2 3 0.77 22.71 6 5 1.28 37.85 10 10 2.56 75.71 20 15 3.84 113.56 30 25 6.40 189.27 50 30 7.68 227.12 60 50 12.80 378.54 100 Drench Dose (Milligrams per 6-in Pot) Drench Volume per 6-in Pot* (Fluid Ounces) ppm Fluid Ounces per Gallon of Final Solution Milliliters per Gallon of Final Solution Milliliters per Liter of Final Solution 0.02 4 0.17 0.04 1.28 0.34 0.03 4 0.25 0.06 1.92 0.51 0.04 4 0.34 0.09 2.56 0.68 0.05 4 0.42 0.11 3.20 0.85 0.06 4 0.51 0.13 3.84 1.01 0.09 4 0.76 0.19 5.76 1.52 0.12 4 1.01 0.26 7.68 2.03 0.20 4 1.69 0.43 12.80 3.38 1Adapted from Hammer, P.A. 1992. * 2 fl oz/4-in pot; 3 fl oz/5-in pot; 10 fl oz/8-in pot.
 Table 23F. Dilution/conversion chart for FLOREL (3.9% active ingredient)1 Spray Spray Solution (ppm) Fluid Ounces per Gallon of Final Solution Milliliters per Gallon of Final Solution Milliliters per Liter of Final Solution 300 0.97 28.72 7.59 325 1.05 331.11 8.22 500 1.62 47.86 12.64 750 2.43 28.89 18.97 975 3.16 93.34 24.66 1,000 3.24 95.73 25.29 1Adapted from Hammer, P.A. 1992.
 Table 23G. Dilution/conversion chart for PRO-GIBB (4% active ingredient)1 Spray Spray Solution (ppm) Fluid Ounces per Gallon of Final Solution Milliliters per Gallon of Final Solution Milliliters per Liter of Final Solution 2.5 0.008 0.24 0.06 5.0 0.016 0.47 0.13 100.0 0.320 9.46 2.50 250.0 0.800 23.66 6.25 300.0 0.960 28.39 7.50 500.0 1.600 47.31 12.50 1Adapted from Hammer, P.A. 1992.
 Table 23H. Dilution/conversion chart for FASCINATION1 Spray ppm BA/GA Fluid Ounces per Gallon of Final Solution Milliliters per Gallon of Final Solution Milliliters per Liter of Final Solution 1/1 0.007 0.2 0.06 5/5 0.04 1.1 0.3 10/10 0.07 2.1 0.6 25/25 0.18 5.3 1.4 50/50 0.36 10.5 2.8 75/75 0.53 15.8 4.2 100/100 0.71 21.0 5.5 1Adapted from Hammer, P.A. 1992.

Tables 24 through 25 are designed to assist growers who desire to prepare their own substrate mix.

 Table 24. Pre-plant fertilizer sources and rates of application1,2 Nutrient Source Rate per Cubic Yard (per m3) Soil-Based Media Soilless Media To provide calcium and magnesium When a pH rise is desired: Dolomitic limestone 0-10 lbs (0-6 kg) 10 lbs (6 kg) When no pH shift is desired: Gypsum for calcium 0-5 lbs (0-3 kg) 0-5 lbs (0-3 kg) Epsom salt for magnesium 0-1 lbs (0-0.6 kg) 0-1 lb (0-0.6 kg) To provide phosphorus* Superphosphate (0-45-0) 1.5 lb (0.9 kg) 2.25 lbs (1.3 kg) To provide sulfur Gypsum (calcium sulfate) 1.5 lbs (0.9 kg) 1.5 lbs (0.9 kg) To provide micronutrients: iron, manganese, zinc, copper, boron, molybdenum Esmigran 3-6 lbs (1.8-3.6 kg) 3-6 lbs (1.8-3.6 kg) Micromax 1-1.5 lbs (0.6-0.9 kg) 1-1.5 lb (0.6-0.9 kg) Promax 1-1.5 lbs (0.6-0.9 kg) 1-1.5 lb (0.6-0.9 kg) F-555HF 3 oz (112 g) 3 oz (112 g) F-111HR 1 lb (0.6 kg) 1 lb (0.6 kg) To provide nitrogen and potassium (optional) Calcium nitrate, or 1 lb (0.6 kg) 1 lb (0.6 kg) Potassium nitrate 1 lb (0.6 kg) 1 lb (0.6 kg) 1From Nelson, P.V. 1998. Greenhouse Operations and Management, 5th ed. Published by Prentice Hall, Inc. Reprinted with permission. 2Rates in this table are for crops other than seedlings. Only limestone is necessary in seedling substrates. Optional nutrient sources for seedling substrate include up to 1 lb (0.6 kg) each of superphosphate, gypsum, and calcium nitrate; no potassium nitrate; and the low end of the rate range for micronutrients. *These are maximum rates designed to supply phosphorus for three to four months if pH is maintained in a desirable range for the crop and the leaching percentage is at or below 20 percent.
 Table 25. Cornell Peat-Lite Mix A for seedlings, bedding plants and potted plants* Materials Used Amount per Cubic Yard1 Amount per Bushel Spagnum peat moss 0.5 cubic yard (13 bushels) 0.5 bushel Horticultural grade vermiculite #2 size for seed germination #2 or 3 for transplanting 0.5 cubic yard (13 bushels) 0.5 bushel Superphosphate, or 1 to 2 pounds 20.5 to 41.0 grams (1 to 2 tablespoons) Treble superphosphate2 0.5 to 1 pound 10.3 to 20.5 grams (0.6 to 1.2 tablespoons) Ground dolomitic limestone2 5 to 10 pounds 103 to 206 grams (5.2 to 10.4 tablespoons) Gypsum2 2.0 pounds 41 grams (2.5 tablespoons) Calcium nitrate 0.5 pound 10 grams (1.2 tablespoons) Potassium nitrate 0.5 pound 10 grams (1.2 tablespoons) Trace element material (Use Only One) Esmigran, or 4.0 pounds 81 grams (4.0 tablespoons) Micromax 1.5 pounds 31 grams (1.7 tablespoons) Wetting agent (Use Only One3) Aqua-Gro 2000 granular, or 1.0 pound --- Aqua-Gro 2000-L liquid4 3-5 fluid ounces 0.5 level teaspoon PsiMatric liquid5 2-4 fluid ounces 0.5 level teaspoon 1A cubic yard equals 27 cubic feet or approximately 22 bushels. A 15 to 20 percent shrink occurs in mixing. Therefore, an additional 5 cubic feet or 4 bushels are used to obtain a full cubic yard. 2If treble superphosphate is used, gypsum is added to supply sulphur. If only 5 pounds of limestone are used for pH control, then add the gypsum that supplied calcium and sulphur. 3The granular Aqua-Grow is preferred. 43 ounces/yard for germination/seedlings, 5 ounces/yard for bedding plants and pot plants. 52 ounces/yard for germination/seedlings, 4 ounces/yard for bedding plants and pot plants. *Adapted from Fonteno. W.C. 1994

 Table 28. Coverage estimates for perlite, peat, topsoil and straw Thickness 4 cu ft Perlite 6 cu ft Canadian peat (compressed) 1 cu yd* Peat mulches, Topsoil, etc. 1 Bale Pinestraw Wheatstraw 2 in 28 sq ft 72 sq ft 162 sq ft 90 sq ft 180 sq ft 1 in 48 sq ft 144 sq ft 324 sq ft 180 sq ft 360 sq ft 1/2 in 96 sq ft 288 sq ft 648 sq ft 360 sq ft 720 sq ft 1/4 in 192 sq ft 576 sq ft 1296 sq ft 720 sq ft 1440 sq ft *1 cubic yard (yd3) = 27 cubic feet (ft3)

Tables 29 through 30 help determine correct spacing and number of plants at each spacing for both greenhouse and field situations.

 Table 29. Plant spacing guide (greenhouse) Spacing Plants/sq ft Plants/A of production area Plants/A of ground covered* 8" x 9" 2.0 87,000 58,000 8" x 8" 2.3 98,000 65,000 8" x 7" 2.6 114,000 76,000 8" x 6" 3.0 130,000 87,000 6" x 7" 3.4 147,000 98,000 6" x 6" 4.0 174,000 116,000 6" x 5" 4.8 208,000 139,000 5" x 5" 5.8 252,000 168,000 5" x 4" 7.2 313,000 209,000 5" x 3" 9.6 418,000 279,000 4" x 3" 12.0 522,000 348,000 *Assuming 1/3 of production area devoted to aisles, etc.
 Table 30. Plant spacing guide (field/orchard)* Spacing Between Rows of Plants Spacing Between Plants Within the Row Feet 6 8 10 12 14 16 18 20 22 24 26 4 1815 1361 1089 907 777 680 605 544 495 453 418 6 1218 907 726 605 518 453 403 363 330 302 279 8 907 680 544 453 388 339 302 272 247 226 209 10 726 544 435 362 311 272 242 218 207 181 167 12 605 453 362 302 259 226 201 181 165 151 139 14 518 388 311 259 222 194 172 155 141 129 119 16 453 339 272 226 194 169 151 136 123 113 104 18 403 302 242 201 172 151 134 121 110 100 93 20 363 272 218 181 155 136 121 108 99 90 83 22 330 247 207 165 141 123 110 99 90 82 76 24 302 226 181 151 129 113 100 90 82 75 69 26 279 209 167 139 119 104 93 83 76 69 64 Number of Plants Per Acre *To determine the number of plants per acre for spacings not given in the table, multiply the distance in the row by the distance between rows and divide that number into 43,560.

## Formulas for calculating greenhouse volume

These formulas are helpful in determining heating and cooling costs for greenhouses.

### For the following formulas:

L = length
W = width
W1 = width of short span
W2 = width of long span
He = height from floor to eave
Hr = height from eave to top

Uneven-span greenhouses

#### Figure 1-A. Formula for calculating uneven-span greenhouse volume.

Greenhouse volume in cubic feet = [(W x He) + ([W1 x Hr] ÷ 2) + ([W2 x Hr] ÷ 2)] x L

Even-span greenhouses

#### Figure 1-B. Formula for calculating even-span greenhouse volume.

Greenhouse volume in cubic feet = [(W x He) + ([W x Hr] ÷ 2)] x L

Quonset structures

#### Figure 1-C. Formula for calculating quonset greenhouse volume.

Greenhouse volume in cubic feet = [(W x He) + ([3.14 x Hr²] ÷ 2)] x L

## Acknowledgments

The authors wish to acknowledge the following sources, certain tables from which were adapted to use in this publication.

• Ball RedBook, 16 ed. 1998. Vic Ball (Ed.) Ball Publishing.
• Bedding Plants IV. 1994. J. Holcomb (Ed.) Ball Publishing.
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Status and Revision History
Published on Mar 1, 2002
Removed as of Feb 24, 2009
Re-published on Apr 29, 2009
Reviewed on Apr 25, 2012
Reviewed on Feb 22, 2016