The pH & TDS/PPM/ec is an essential factor of the plant's health as it will affect how well each element can be absorbed through the roots and eventually will nourish the plant. When pH & TDS is not ideal for plant, nutrient won't be absorbed by the plant and this is called "Nutrient Lock-out". We can measure the pH & TDS using tools such as Digital pH & TDS meter or even test strips (pH only)

Fig. 1 : Vegetable pH & PPM Requirement Table :

Name pH PPM eC
Ampalaya (Bitter Gourd) 6.4-6.7 1190-1750 2.38-3.5
Asparagus 6.0-6.8 1400-2800 2-4
Basil 5.5-6.5 700-1120 1.0-1.6
Beans 6.0-6.5 N/A N/A
Broccoli 6.0-6.5 1960-2450 2.8-3.5
Cabbage 6.5-7.0 1750-2100 2.5-3.0
Capsicum 6.0-7.5 1260-1540 1.8-2.2
Cauliflower 6.0-7.0 1050-1400 0.5-2.0
Celery 6.0-7.0 1260-1680 1.8- 2.4
Cucumber 5.8-6.0 1190-1750 1.7-2.5
Eggplant 5.5-6.5 1750-2450 2.5-3.5
Kangkong 5.5-6.0 600-1200 1.2 to 2.4
Leeks 6.5-7.0 980-1260 1.4-1.8
Lettuce 5.5-6.5 560-840 0.8-1.2
Melon 5.5-6.0 1400-1750 2.0-2.5
Mustasa (Mustard Greens) 5.5-6.5 600-1200 1.2 to 2.4
Okra 6.5 1400-1680 2.0-2.4
Onions 6.0-6.7 980-1260 1.4-1.8
Pak-choi / Bok-choi 7.0 1050-1400 1.5-2.0
Peppers (Bell peppers, Green Chili) 5.8-6.3 1400-2100 2.0-3.0
Peppers (Super hot) 6.0-6.5 2100-2450 3.0-3.5
Petchay 5.5-6.5 600-1200 1.2 to 2.4
Pumpkin 5.5-7.5 1260-1680 1.8-2.4
Strawberry 5.5-6.0 800-1,200 1.6-2
Tomato 5.5-6.5 1400-3500 2.0-5.0
Watermelon 5.8 1050-1680 1.5-2.4
Zucchini 5.8 1260-1680 1.8-2.4

Terminologies :

  • pH = potential of hydrogen, it is a scale used to specify the acidity or alkalinity(basicity) of an aqueous compound.
  • TDS = Total Dissolved Solids, it is a measurement of the dissolved content of all inorganic and organic substances .
  • PPM = Parts Per Million, milligrams per liter (mg/L)
  • EC = Electrical Conductivity, it is the measurement of the amount of electrical current a material can carry or it's ability to carry a current