Artificial Soil Media

General (Non-Specific) Guidelines for Artificial Soil Media

CATEGORY
Analysis Low Acceptable Optimum High Very High
pH (peat based medium) 0-5.3 5.4-5.5 5.6-5.8 5.9-6.5 6.5+
Soluble Salts mhos/cm* 0-0.74 0.75-1.9 2.0-3.4 3.5-5.0 5.1+
Nitrate-N (NO3-N) ppm 0-.39 40-99 100-199 200-299 300+
Ammonium -N (NH4-N) ppm 0-5 5-15 16-20 20+
Phosphorus (P) ppm 0-2 3-5 6-9 11-18 19+
Potassium (K) ppm 0-59 60-149 150-249 250-349 350+
Calcium (Ca) ppm 0-79 80-199 200+
Magnesium (Mg) ppm 0-29 30-69 70+
Boron (B) ppm 0.05-0.50
Copper (Cu) ppm 0.005-0.5
Iron (Fe) ppm 0.3-3.0
Manganese (Mn) ppm 0.02-3.0
Zinc (Zn) ppm 0.3-3.0
Molybdenum (Mo) ppm 0.01-0.10
Aluminum (Al) ppm < 5
Sodium (Na) ppm < 50
Chloride (Cl) ppm < 9 9.1-20 20.1+

*mmhos/cm is interchangeable with mS/cm. Multiply mmhos/cm by 700 to convert to ppm.

Desirable Nutrient Balance in Saturated Paste Extract

Nutrient % of Total Soluble Salt
Nitrate-N (NO3-N) 8-10
Ammonium-N (NH4-N) < 3
Potassium (K) 11-13
Calcium (Ca) 16-16
Magnesium (Mg) 4-6
Sodium (Na) < 10
Chloride (Cl) < 10

*While the above values are considered to be the most desirable, other levels in approximately the same proportions will likely permit good plant growth, as long as the total soluble salts are not too high. Faster growing plants will normally tolerate somewhat higher total soluble salt levels in the growing media. Higher total soluble salts are better tolerated by plants in a balanced nutrient situation.

Suggested Ranges for Selected Crops

Crop pH EC mmhos/cm NO3-N (ppm) P (ppm) K (ppm) Ca (ppm) Mg (ppm)
Seedlings (Any) 5.6-5.8 0.7-1.0 40-70 5-9 100-175 100-200 50-100
Young potted plants 5.6-5.8 1.0-2.0 50-90 6-10 100-175 100-200 50-100
Potted plants (general) 5.6-5.8 1.5-3.0 80-160 6-10 175-250 250-325 80-125
Bedding plants 5.6-5.8 2.0-3.5 100-200 6-10 150-250 200-400 70-140
Foliage plants 5.6-5.8 1.0-2.0 50-90 6-10 100-175 100-200 50-100
Woody ornamentals 5.6-5.8 1.0-1.5 80-100 8-12 20-40 20-40 15-20
Azaleas, Rhododendrons, Gardenias, Camellias, Blue Hydrangeas 5.0-5.5 0.5-0.8 40-50 4-6 10-20 10-20 7-10
Roses, Mums, Snapdragons 5.6-5.8 2.0-3.5 120-200 10-15 200-275 100-200 50-100
Lettuce 5.6-5.8 2.0-3.5 120-200 10-15 200-275 100-200 50-100
Tomatoes 5.6-5.8 2.0-3.5 120-200 10-15 200-275 100-200 50-100

Adjusting the pH of Soil-Less Media

Acidifying Media to pH 5.7 from Listed Beginning pH

COMPOSITION OF MEDIA MATERIAL
50% Peat-50% Sand 50% Peat-50% Bark 100% Peat
Beginning pH Lbs sulfur/cu. yd.
7.5 1.7 2.0 3.4
7.0 1.2 1.5 2.5
6.5 0.8 1.0 2.0

Note: Finely ground sulfur, as recommended above is slow acting. Substituting iron sulfate at the appropriate equivalent rate listed below is considered a moderately fast reaction, and aluminum sulfate at the appropriate equivalent rate is considered fast acting.

Common Acidifying Materials

Material Chemical Formula Percent Sulfur Lbs of material to Equal 100 lbs of Sulfur
Elemental Sulfur S 90.0 110
Sulfuric Acid H2SO4 32.0 306
Sulfur Dioxide SO2 50.0 200
Iron Sulfate FeSO4 11.5 869
Aluminum Sulfate Al2(SO4)3 14.4 694
Ammonium Sulfate (NH4)2SO4 23.7 422

Liming Media to pH 5.7 From Listed Beginning pH

COMPOSITION OF MEDIA MATERIAL
50% Peat-50% Sand 50% Peat-50% Bark 100% Peat
Beginning pH Lbs. Dolomitic Lime/cubic yard
5.0 1.7 2.5 3.5
4.5 3.7 5.6 7.4
4.0 5.7 7.9 11.4
3.5 7.8 10.5 15.5

Note: Additions of more than 10 lbs of dolomitic limestone yard3 often causes micronutrient deficiencies.

Nitrogen (N)

To Increase Test Level 10 ppm, Use the Following Rates of the Product Listed
Product % N Product Oz./bu N lbs/100 bu Product oz/yd3 N lb/100 yd3 Product oz/100 ft2 N/1000 ft2
Potassium Nitrate 13.0 0.12 0.10 2.30 1.87 4.60 0.37
Calcium Nitrate 15.0 0.10 0.09 2.00 1.88 4.00 0.38
Ammonium Nitrate 33.0 0.005 0.09 0.90 1.56 1.80 0.37
Urea 45.0 0.04 1.10 0.70 1.97 1.40 0.39

Phosphorus (P)

To Increase Test Level 2 ppm, Use the Following Rates of the Product Listed
Product % P2O5 Product Oz./bu P2O5 lbs/100 bu Product oz/yd3 P2O5 lb/100 yd3 Product oz/100 ft2 P2O5/1000 ft2
Normal Superphosphate 20.0 0.75 0.94 0.90 1.1 1.80 0.23
Concentrated Superphosphate 46.0 0.33 0.95 0.40 1.2 0.80 0.23
Bone Meal 25.0 0.60 0.94 0.75 1.2 1.50 0.23

Potassium (K)

To Increase Test Level 25 ppm, Use the Following Rates of the Product Listed
Product % K2O Product Oz./bu K2O lbs/100 bu Product oz/yd3 K2O lb/100 yd3 Product oz/100 ft2 K2O/1000 ft2
Potassium Nitrate 44.0 0.19 0.52 3.75 10.3 0.46 0.13
Potassium Sulfate 50.0 0.16 0.50 3.25 10.2 0.40 0.13
20-20-20 20.0 0.41 0.51 8.25 10.3 1.03 0.13

Calcium (Ca)

To Increase Test Level 25 ppm, Use the Following Rates of the Product Listed
Product % Ca Product Oz./bu Ca lbs/100 bu Product oz/yd3 Ca lb/100 yd3 Product oz/100 ft2 Ca/1000 ft2
Calcitic Lime 32.0 0.21 0.42 4.20 8.40 0.53 0.11
Dolomitic Lime 22.0 0.30 0.41 6.00 8.25 0.75 0.10
Gypsum 23.0 0.29 0.42 5.80 8.34 0.73 0.10
Calcium Nitrate 19.0 0.35 0.42 7.00 8.31 0.88 0.10
Normal Superphosphate 20.0 0.33 0.41 6.70 8.38 0.84 0.11
Concentrated Superphosphate 13.0 0.51 0.41 10.20 8.29 1.28 0.10

Magnesium (Mg)

To Increase Test Level 25 ppm, Use the Following Rates of the Product Listed
Product % Mg Product Oz./bu Mg lbs/100 bu Product oz/yd3 Mg lb/100 yd3 Product oz/100 ft2 Mg/1000 ft2
Epsom Salts 11.0 0.61 0.42 12.22 8.40 1.54 0.11
Dolomitic Lime 10.0 0.66 0.41 13.20 8.25 1.65 0.10
K-Mag 11.0 0.61 0.42 12.13 8.34 1.53 0.10
Magnesium Nitrate 16.0 0.42 0.42 8.31 8.31 1.05 0.10
Magnesium Chloride (flake) 12.2 0.54 0.41 10.98 8.38 1.38 0.11
Magnesium Chloride (solution) 7.5 0.88 0.41 17.68 8.29 2.22 0.10

General Micronutrient Recommendations for Crops in Artificial Media

Bench Drench Container Drench
Nutrient Source* Analysis % Oz/100 ft2 g/100 ft2 Oz/100 gal g/100 gal Nutrient Rate (ppm)
Iron (Fe)
Ferrous Sulfate 0.2 16.00 454 50 1418 750
Boron (B)
Solubor 20.0 0.28 7.8 0.55 15.6 8.3
Sodium Tetraborate (Borax) 11.0 0.50 14.2 1.0 28.4 8.3
Boric Acid 17.5 0.60 17.0 0.65 18.4 8.5
Manganese (Mn)
Manganese Sulfate 33.0 0.38 21.3 0.1 2.8 2.4
Zinc (Zn)
Zinc Sulfate 23.0 0.38 21.3 0.1 2.8 1.7
Copper (Cu)
Copper Sulfate 25.0 0.38 21.3 0.1 2.8 1.9
Molybdenum (Mo)aa
Ammonium Molybdate 54.0 Quantity too small for uniform application 0.025 0.7 1.0
Sodium Molybdate 46.6 Quantity too small for uniform application 0.029 0.8 1.0

*Where commercial chelates are used, follow label directions.

aaDissolve 1 oz. sodium or ammonium molybdate in 40 fl. oz. of water. Use 1 fl. oz. of this stock solution in 100 gal. of final strength fertilizer solution.

Suggested General Micronutrient Formulations for Artificial Soil Media

Compound Analysis Quantity to use per cubic yard
Iron Chelate 6.0% Fe 1 oz.
Manganous Sulfate 26.0% Mn 1 oz.
Copper Sulfate 25.0% Cu 0.3 oz.
Zinc Sulfate 36.0% Zn 0.2 oz.
Sodium Borate (Borax) 11.0% B 0.1 oz.
Sodium Molybdate 39.0% Mo 0.03 oz.

Source: Greenhouse Growth Media: Testing and Nutrition Guidelines, Bulletin E1736 by Darryl D Warncke and Dean M. Krauskopg, Michigan State University

 
library/articles/artificial_soil_media_guidelines.txt · Last modified: 2013/07/15 09:27 by bill