Hydroponics FAQ Part 1 – Water Control

Hydroponics FAQ – Water Control pH & EC

Having an understanding of how much food a plant requires helps massively as a gardener, however some don’t find it as easy, and forgoing the much-needed digital meters will only leave you growing blind and possibly more confused.

Hopefully this quick FAQ will help make the decision a little easier to purchase these meters, your plants will thank you.

What is EC? 

EC (Electrical conductivity) is a type of meter used in hydroponics to see if there is an electrical charge within a nutrient solution, most growers use EC as an indication as to whether they have too much or too little food presently available to the plant. 

EC is measured in milliSiemens per centimetre (mS/cm)

Once a specific element has been added to a working solution it divides into two charges called Ions

- Positively charged ions are Cations

- Negatively charged ions are Anions

The higher the ionic value of a nutrient solution, the higher the EC will register.

What EC should I maintain?

EC requirements change as the plant grows from seedling into a mature plant. 

When your plants are young they require less food, so it makes sense that as the plant grows we increase the amount of food to fulfil the plant’s daily requirements.

A digital EC meter will take out the guess work, allowing you to achieve the numbers below, giving your plants exactly what they need.

Seedling requirements: 0.2 – 0.6 EC

Growth/Vegetative requirements: 0.6 - 1.2 EC

Bloom/Flowering requirements: 1.4 - 2.2 EC

Flowering Maturation: 0.0 – 0.3 EC

What is pH and what pH should I maintain?

pH stands for Power of Hydrogen.

When the pH fluctuates too much the plant will be unable to uptake specific 'immobile'  nutrients/elements. Stability is key.

Regularly checking your pH level informs you whether or not your plants roots are in an environment that they can thrive in.

Plants can easily consume nutrients/elements when the pH of the nutrient solution is in range. Most plants hydroponically grown, will grow perfectly between the pH range of 5.5– 6.5

If the pH range goes outside of this 5.5-6.5 pH window, some nutrients/elements will become “unavailable” to the plant, resulting in deficiencies and growth problems.

A digital pH meter is recommended to make sure your nutrient solution is readily available for your plants to consume when needed:

  • Seedling requirements: 5.6 - 5.9
  • Growth/Vegetative requirements: 5.7 - 6.0
  • Bloom/Flowering requirements: 5.9 – 6.2
  • Flowering maturation: 5.8 – 6.2


Water Control FAQ - A-Grade Hydroponics

What temperature should I maintain for my water, reservoir or nutrient solution?

The temperature of your water or nutrient solution will affect the pH reading, altering it up or down depending on the temperature of the water, although these differences are rather minor, they do exist.

The best rule of thumb to follow for water temperature is to maintain between 17c - 22c celsius where possible.

If your water drops below or rises above the suggested temperatures for periods of time, no harm will be done if the water is stored properly without plants submerged in it.

The real concern comes when running a hydroponic system where water is coming in contact with plants that is outside of the safe temperature range, resulting in potential growth of pathogens and diseases due to high water temperatures or shock and stunted growth due to low temperatures.

This becomes an important metric to monitor and control when using Deep Water Culture (DWC) systems, Nutrient Film Technique (NFT) or most recirculating systems.


-Revised and updated 11/9/20


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