A reference guide to grouping plants for hydroponic and Autopot systems.  We use cF (conductivity Factor) to measure the strength of the nutrient.  This measures the amount of electrical current that passes through the water.

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

Plant cF can vary according to the stage of growth.  Eg cucumber likes a cF around 20 when establishing, a cF of around 25 after the first harvest and then drops to about 17 after a few weeks.

You can group within the categories provided the middle cF is used.

pH measures the acidity of the water

With Autopots you need to remember to clean the tank and flush the pipes with fresh water when refilling the tank.

In a reticulating hydroponic system the balance of the nutrient can change.  Often I have cutomers who come in and say the system worked well to start but now the plants aren’t doing so well.    The plant uptakes nutrients at different rates during the different stages of growth.  To keep the nutrient in balance you must flush the system at regular intervals and refresh the nutrient.

The nutrient solution should be totally discarded and the pipes rinsed with clean water to ensure you don’t get build up or blockage.  If you try to reuse the water and existing nutrient you will end up with an imbalance of the salts required for optimum plant growth.

Vegetables

Plants
pH
cF
Category
Ambra radicchio 5.5-6.5
Artichoke 6.5-7.5 8-18 L
Asparagus 6.0-6.8 14-18 L
Bean 6.0 20-40 H
Beetroot 6.0-6.5 8-50
Broad Bean 6.0-6.5 18-22 M
Broccoli 6.0-6.5 28-35 H
Brussell Sprout 6.5-7.5 25-30 H
Cabbage 6.5-7.0 25-30 H
Capsicum 6.0-6.5 18-22 M
Carrots 6.3 16-20 M
Cauliflower 6.0-7.0 5-20 M
Celery 6.5 18-24 M
Collard greens 6.5-7.5
Cucumber 5.8-6.0 17-25 M
Eggplant 5.5-6.5 25-35 H
Endive 5.5 20-24 M
Fodder 6.0 18-20 M
Garlic 6.0 14-18 L
Leek 6.5-7.0 14-18 L
Lettuce 5.5-6.5 8-12 L
Marrow 6.0 18-24 M
Okra 6.5 20-24 M
Onions 6.0-6.7 14-18 L
Pak-choi 7.0 15-20 M
Parsnip 6.0 14-18 L
Pea 6.0-7.0 8-18 L
Peas (Sugar) 6.0-6.8 L
Pepino 6.0-6.5 20-50 H
Peppers 5.8-6.3 20-30 H
Bell peppers 6.0-6.5 20-25 M
Hot Peppers 6.0-6.5 30-35 H
Potato 5.0-6.0 20-25 M
Pumpkin 5.5-7.5 18-24 M
Radish 6.0-7.0 16-22 M
Spinach 5.5-6.6 18-23 M
Silverbeet 6.0-7.0 18-23 M
Sweet Corn 6.0 16-24 M
Sweet Potato 5.5-6.0 20-25 H
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 H
Tomato 5.5-6.5 20-50 H
Turnip 6.0-6.5 18-24 M
Zucchini  6.0 18-24 M

Herbs

Plants
pH
cF
Category
Basil 5.5-6.5 10-16 L
Chicory 5.5-60 20-24 H
Chives 6.0-6.5 18-22 M
Fennel 6.4-6.8 10-14 L
Lavender 6.4-6.8 10-14 L
Lemon Balm 5.5-6.5 10-16 L
Marjoram 6.0 16-20 M
Mint 5.5-6.0 20-24 H
Mustard Cress 6.0-6.5 12-24 M
Parsley 5.5-6.0 8-18 L
Rosemary 5.5-6.0 10-16 L
Sage 5.5-6.5 10-16 L
Thyme 5.5-7.0 8-16 L
Watercress 6.5-6.8 4-18 L

Flowers

Plants
pH
cF
Category
African Violets 6.0-7.0 12-15 L
Anthurium 5.0-6.0 16.20 L
Antirrhinim 6.5 16-20 L
Aphelandra 5.0-6.0 18-24 M
Aster 6.0-6.5 18-24 M
Begonia 6.5 14-18 L
Bromeliads 5.0-7.5 8-12 L
Caladium 6.0-7.5 16-20 L
Canna 6.0 18-24 M
Carnation 6.0 20-35 M-H
Chrysanthemum 6.0-6.2 18-25 M
Cymbidiums 5.5 6-10 L
Dahlia 6.0-7.0 15-20 L
Dieffenbachia 5.0 18-24 M
Dracaena 5.0-6.0 18-24 M
Ferns 6.0 16-20 L
Ficus 5.5-6.0 16-24 L
Freesia 6.5 10-20 L
Impatiens 5.5-6.5 18-20 L
Gerbera 5.0-6.5 20-25 M
Gladiolus 5.5-6.5 20-24 M
Monstera 5.0-6.0 18-24 M
Palms  6.0-7.5 16-20 M
Roses 5.5-6.0 15-25 M
Stock 6.0-7.0 16-20 L

Fruit

Plants
pH
cF
Category
Banana 5.5-6.5 18-22 M
Black Currant 6.0 14-18 L
Blueberry 4.0 -5.0 18-20 M
Melon 5.5-6.0 20-25 H
Passionfruit 6.5 16-24 M
Paw-Paw 6.5 20-24 H
Pineapple 5.5-6.0 20-24 H
Red Currant 6.0 14-18 M
Rhubarb 5.0- 6.0 16-20 M
Strawberries 5.5-6.5 18-22 M
Watermelon 5.8 15-24 M