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+

Phosphorous (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

Phosphorous (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)**

Ammonium Molybdate

54.0

Quantity too small for uniform application

0.025

0.7

1.0

Sodium Molybdate

46.6

0.029

0.8

1.0

*Where commercial chelates are used, follow label directions.

**Dissolve 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