pH/ TDS / PPM / EC of Water for Hydroponic Plants

We often get asked what the nutrient requirements are for specific plants, and this is the informative article we refer to.

The pH and electro-conductivity values specified here are just vague guidelines. Your specific plant growing requirements will vary according to regional climatic conditions, and from season to season within that region. 

EC reading should be monitored. These values for hydroponic plants only (soil-grown plants will differ slightly). 

The concentration of salts ms cm is what we measure with an EC or ppm meter. 

Nutrients generally dissolve in water and provide resistance measured by EC & PPM Meters. 

Positively charged ions conduct electricity measured in ppm

Temperature affects the pH of water however most good pH meters have automatic temperature compensation.

Some cheap pH meters come with a sachet that you dissolve in distilled water 

Consider buying a pH Meter & EC Meter to feed your plants nutrient accurately.

Electro-Conductivity (EC) or Conductivity Factor (cF) can be expressed as either milliSiemens (mS), cF, or parts per million (PPM) 1 mS = 10cF = 700ppm.

Joining a hydroponic community forum relating to the plant you are growing to unlock your full potential with maximum yields.

Check out: Simple Guide to Understanding Nutrient Concentration for more

 


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 20-30 2.0-3.0 1400-2100
Bell peppers 6.0-6.5 20-25 2.0-2.5 1400-1750
Hot Peppers 6.0-6.5 30-35 3.0-3.5 2100-2450
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

 

Cannabis is grown Indoors:

Max 1.4 EC / 700 ppm * during Vegetative phase

Max 1.6EC / 800 ppm * during Flowering phase.

a pH of 5.5 - 5.8 

* without co2 injection and control.

 

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

 

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Some information sourced from www.homehydrosystems.com/ph_tds_ppm/ph_vegetables_page.html

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Comments

Cedric Whittal - November 2, 2019

I have just started with hydroponic growing. I am just tomatoes to start. My Ph is correct at 6 but after I have added the nutrients as per the instructions, my ppm only reads 575ppm and my EC is 1208uS/cm.. Do I need any adjustments in the nutrients. I use the 3 bottle system, Grow, Micro and Bloom.
Hope you can help in this regard.

Cheers
Cedric

Tony Venning-Thomas - August 1, 2019

I would like to grow other crops with my lettuce plants at the same ph/cf ,any suggestions

Steve Keith - August 1, 2019

Do these EC figures include what the initial conditions are? When I set the ph level before nutrients I measure .7 EC – should I add this on to the figures here? Thank you.

John Sandison - May 17, 2019

Could you kindly supply me with the correct EC for growing OATS hydroponically.
Thank you
John

Muhammad Sadiq - May 17, 2019

Dear sir/mam
Will you please tell me details for sugarcane

Chandra Shekhar Kanth - May 17, 2019

Sir,
After doing two days hydroponic initial course, I setup two NFT & two DWC of cucumber, okra, tomato, spinach, brinjal, sponge gourd, pumpkin and Bitter gourd. After germination of seeds I put the small plant in the system and nutrition purchased from garden guru A & B circulation start with EC 800, PH 7 in RO Water. Only bitter gourd plant develop and rest is not develop after 35 days. So I want to get more knowledge of EC, ph, nutrition.

jimmy - May 17, 2019

What about strawverry?

Nishal Ghoora - January 29, 2019

Hello Sir,
i was inquiring for EC level of Patty Pan squash,
yet seeing no records,on there for summer n winter .
Kindly do inform me,
Thanks

Shubha Banerjee - January 29, 2019

Wonderful compilation of useful information

Karnel Singh - January 29, 2019

Dear Sir / Mam
Would you plz tell me TDS for azolla cultivation .

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