pH and Electrical Conductivity

The pH and electro-conductivity values specified here are given as a broad range. It should be noted that specific plant requirements will vary according to regional climatic conditions, and from season to season within that region. These values are intended for hydroponic plants only (soil grown plants will differ). Electro-Conductivity (EC) or Conductivity Factor (cF) can be expressed as either milliSiemens (mS), cF, or parts per million (PPM) 1 mS = 10cF = 700ppm.

 

As a general rule, plants will have a higher nutrient requirement during cooler months, and a lower requirement in the hottest months. Therefore, a stronger nutrient solution should be maintained during winter, with a weaker solution during summer, when plants take up and transpire more water than nutrients.

 

Fruits

Plants
pH
cF
EC
PPM

Banana

5.5-6.5

18-22

1.8-2.2

1260-1540

Black Currant

6.0

14-18

1.4-1.8

980-1260

Blueberry

4.0 -5.0

18-20

1.8-2.0

1260-1400

Melon

5.5-6.0

20-25

2.0-2.5

1400-1750

Passionfruit

6.5

16-24

1.6-2.4

840-1680

Paw-Paw

6.5

20-24

2.0-2.4

1400-1680

Pineapple

5.5-6.0

20-24

2.0-2.4

1400-1680

Red Currant

6.0

14-18

1.4-1.8

980-1260

Rhubarb

5.0- 6.0

16-20

1.6-2.0

840-1400

Strawberries

5.5-6.5

18-22

1.8-2.2

1260-1540

Watermelon

5.8

15-24

1.5-2.4

1260-1680

 

 

Vegetables

Plants
pH
cF
EC
PPM

Ambra radicchio

5.5-6.5

 

 

 

Artichoke

6.5-7.5

8-18

0.8-1.8

560-1260

Asparagus

6.0-6.8

14-18

1.4-1.8

980-1260

Bean (Common)

6.0

20-40

2-4

1400-2800

Beans (Italian bush) 

6.0-6.5

 

 

 

Beans (Lima)

6.0-6.5

 

 

 

Beans (Pole)

6.0-6.5

 

 

 

Beetroot

6.0-6.5

8-50

0.8-5

1260-3500

Broad Bean

6.0-6.5

18-22

1.8-2.2

1260-1540

Broccoli

6.0-6.5

28-35

2.8-3.5

1960-2450

Brussell Sprout

6.5-7.5

25-30

2.5-3.0

1750-2100

Cabbage

6.5-7.0

25-30

2.5-3.0

1750-2100

Capsicum

6.0-6.5

18-22

1.8-2.2

1260-1540

Carrots

6.3

16-20

1.6-2.0

1120-1400

Cauliflower

6.0-7.0

5-20

0.5-2.0

1050-1400

Celery

6.5

18-24

1.8- 2.4

1260-1680

Collard greens

6.5-7.5

 

 

 

Cucumber

5.8-6.0

17-25

1.7-2.5

1190-1750

Eggplant

5.5-6.5

25-35

2.5-3.5

1750-2450

Endive

5.5

20-24

2.0-2.4

1400-1680

Fodder

6.0

18-20

1.8-2.0

1260-1400

Garlic

6.0

14-18

1.4-1.8

980-1260

Leek

6.5-7.0

14-18

1.4-1.8

980-1260

Lettuce

5.5-6.5

8-12

0.8-1.2

560-840

Marrow

6.0

18-24

1.8-2.4

1260-1680

Okra

6.5

20-24

2.0-2.4

1400-1680

Onions

6.0-6.7

14-18

1.4-1.8

980-1260

Pak-choi

7.0

15-20

1.5-2.0

1050-1400

Parsnip

6.0

14-18

1.4-1.8

980-1260

Pea

6.0-7.0

8-18

0.8-1.8

980-1260

Peas (Sugar)

6.0-6.8

 

 

 

Pepino

6.0-6.5

20-50

2.0-5.0

1400-3500

Peppers

5.8-6.3

 

 

 

Bell peppers

6.0-6.5

 

 

 

Hot Peppers

6.0-6.5

 

 

 

Potato

5.0-6.0

20-25

2.0-2.5

1400-1750

Pumpkin

5.5-7.5

18-24

1.8-2.4

1260-1680

Radish

6.0-7.0

16-22

1.6-2.2

840-1540

Spinach

5.5-6.6

18-23

1.8-2.3

1260-1610

Silverbeet

6.0-7.0

18-23

1.8-2.3

1260-1610

Sweet Corn

6.0

16-24

1.6-2.4

840-1680

Sweet Potato

5.5-6.0

20-25

2.0-2.5

1400-1750

Swiss chard

6.0 6.5

 

 

 

Squash (Summer)

5.0-6.5

 

 

 

Squash (Winter)

5.0-6.5

 

 

 

Taro

5.0-5.5

25-30

2.5-3.0

1750-2100

Tomato

5.5-6.5

20-50

2.0-5.0

1400-3500

Turnip

6.0-6.5

18-24

1.8-2.4

1260-1680

Zucchini

 

6.0

18-24

1.8-2.4

1260-1680

 

 

Herbs

Plants
pH
cF
EC
PPM

Basil

5.5-6.5

10-16

1.0-1.6

700-1120

Chicory

5.5-60

20-24

2.0-2.4

1400-1600

Chives

6.0-6.5

18-22

1.8-2.4

1260-1540

Fennel

6.4-6.8

10-14

1.0-1.4

700-980

Lavender

6.4-6.8

10-14

1.0-1.4

700-980

Lemon Balm

5.5-6.5

10-16

1.0-1.6

700-1120

Marjoram

6.0

16-20

1.6-2.0

1120-1400

Mint

5.5-6.0

20-24

2.0-2.4

1400-1680

Mustard Cress

6.0-6.5

12-24

1.2-2.4

840-1680

Parsley

5.5-6.0

8-18

0.8-1.8

560-1260

Rosemary

5.5-6.0

10-16

1.0-1.6

700-1120

Sage

5.5-6.5

10-16

1.0-

700-1120

Thyme

5.5-7.0

8-16

0.8-1.6

560-1120

Watercress

6.5-6.8

4-18

0.4-1.8

280-1260

 

 

Flowers

Plants
pH
cF
EC
PPM

African Violets

6.0-7.0

12-15

1.2-1.5

840-1050

Anthurium

5.0-6.0

16.20

1.6-2.0

1120-1400

Antirrhinim

6.5

16-20

1.6-2.0

1120-1400

Aphelandra

5.0-6.0

18-24

1.8-2.4

1260-1680

Aster

6.0-6.5

18-24

1.8-2.4

1260-1680

Begonia

6.5

14-18

1.4-2.4

980-1260

Bromeliads

5.0-7.5

8-12

0.8-1.2

560-840

Caladium

6.0-7.5

16-20

1.6-2.0

1120-1400

Canna

6.0

18-24

1.8-2.4

1260-1680

Carnation

6.0

20-35

2.0-3.5

1260-2450

Chrysanthemum

6.0-6.2

18-25

1.8-2.5

1400-1750

Cymbidiums

5.5

6-10

0.6-1.0

420-560

Dahlia

6.0-7.0

15-20

1.5-2.0

1050-1400

Dieffenbachia

5.0

18-24

1.8-2.0

1400-1680

Dracaena

5.0-6.0

18-24

1.8-2.4

1400-1680

Ferns

6.0

16-20

1.6-2.0

1120-1400

Ficus

5.5-6.0

16-24

1.6-2.4

1120-1680

Freesia

6.5

10-20

1.0-2.0

700-1400

Impatiens

5.5-6.5

18-20

1.8-2.0

1260-1400

Gerbera

5.0-6.5

20-25

2.0-2.5

1400-1750

Gladiolus

5.5-6.5

20-24

2.0-2.4

1400-1680

Monstera

5.0-6.0

18-24

1.8-2.4

1400-1680

Palms

6.0-7.5

16-20

1.6-2.0

1120-1400

Roses

5.5-6.0

15-25

1.5-2.5

1050-1750

Stock

6.0-7.0

16-20

1.6-2.0

1120-1400