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 milliSiemens (mS), cF, or parts per million (PPM) 1 mS = 10cF = 700ppm.

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