Meters
The pH value is important for growers when it comes to watering and fertilising their plants, but also to monitor the pH value of the medium. What is the pH value?
pH (Potentia Hydrogenii) is the logarithmic scale for measuring the acid and base concentration of a solution, ranging from 0 to 14 and from acidic to alkaline. A value of 7 is neutral, below it is more acidic and above it is more alkaline. The pH scale multiplies each point by a factor of 10, in other words: a value of 5 is ten times more alkaline than a value of 4. Rainwater, for example, usually has a pH value of 6.
What is the EC value?
EC (Electric Conductivity) indicates the electrical conductivity of a substance. In water or liquid media, the salt content influences the electrical conductivity; the saltier a solution, the higher the conductivity and therefore the EC value. It is given in S/m (Siemens per metre) or, in the case of measuring devices, usually as mS/cm (mS for short). Growers are interested in the EC value of the water, the growing medium and their fertiliser solutions. The EC value provides the most accurate measurements of the nutrients contained.
Which values are ideal for growing?
The ideal pH and EC values for successful growing depend on three factors: The growing medium, the water and the nutrients. For those growing on soil, a pH value of 6 to 6.5 is ideal. If you are growing in coco or using a hydroponic system, you need to pay closer attention to the pH value. A value of 5.8 is ideal, but should be at least within a range between 5.5 and 6.1.
The perfect EC value depends on the plant species. Plants with low nutrient requirements prefer an EC value of 1.0 so as not to be over-fertilised, while plants with higher nutrient requirements require an EC value of 2.5 to 3.
What are the measured values for water and grow medium?
Water has an EC value of around 0.5 mS and is usually pH-neutral, i.e. has a pH value of 7. Specialised growing soil usually has a pH value of 6. Soil is a comparatively forgiving medium and acts as a buffer for the root zone. Hydroponic clay pebbles and perlite are initially sterile media and therefore neutral. Here you need to pay closer attention to the pH and EC values caused by water and fertilisers.
Hydroponic cultivation - fine-tuning is important here
In contrast to low-maintenance, organic soil cultivation, hydroponic cultivation requires more fine-tuning. In this respect, the conscientious grower must carefully control the nutrient dosage and measure the values for each fertilisation. Fluctuations in pH and EC values should be avoided as far as possible. While the pH value of the water should remain constant, the EC value is gradually increased according to the growth phase of the plant. The draining water should be checked regularly - about once a week - to prevent the accumulation of salts and thus over-fertilisation. As a general rule, fertilisers should be used carefully. The majority of problems are caused by growers who mean too well when applying nutrients.
How to check pH and EC values
There are numerous practical tools available to help growers monitor pH and EC values. Beginners can get started inexpensively with pH tests for water and soil, the Milwaukee EC tester or an EC meter from Adwa, for example. Devices that permanently monitor the EC or pH value in the nutrient solution are available for less than 100 euros each. If you invest a little more, you can get measuring devices that permanently monitor both values and issue warnings in the event of deviations. This makes successful cultivation in Hydroponic Systems in particular much easier.