EC meters are a very useful tool when growing cannabis since they allow growers to have full control over the nutrition of their plants. Today, with tens of nutrient brands offering their own formulations, it may be difficult to find the correct dosage for your plants, especially when nutrients or additives of different brands are mixed. Well, with the help of an EC meter you can easily check the exact amount of nutrients contained in your nutrient solution, which, as you’ll see in this article, makes things a lot easier.
EC meters are electronic devices which can either operate on batteries (portable models) or directly plugged into the mains (continuous meters). They measure the electrical conductivity of fluids, that is to say, the amount of salts dissolved in the water (the material’s capacity to conduct electric current). In this way, conductivity levels tell you the amount of salts (nutrients) contained in your nutrient solution.
Cannabis plants require a varying nutrition according to their growth stage. With the help of an EC meter, and especially in the case of hydroponic cultivation (coco coir, clay pebbles, deep water culture, etc), you can easily check the amount of nutrients and thus give your plants the correct nutrition.
These meters operate with electrodes, which are submerged in the water tank and immediately give a reading of the electrical conductivity of the solution. Once you know this value, you can add more nutrients or more water whether you need to raise or lower the EC of the nutrient solution.
How to use EC meters in cannabis cultivation
Types of EC meters and reasons why you should be using one
There are basically two types of EC meters, portable (manual) and continuous meters. Portable EC meters are small units, easy to carry and use, which give you the EC reading once you submerge the electrodes in the solution. On the other hand, continuous EC meters are always connected and with the electrode constantly submerged in the tank, so you can check the EC anytime by just taking a look at the digital display. They’re mainly used in recirculating systems, with which you must check the EC almost everyday.
In recirculating systems like GHE EBB&GROW, the nutrient solution goes from the reservoir to the plants and then back to the reservoir, so carefully checking the nutrient solution every day is advised. Both the water level and amount of nutrients will decrease over time and as plants are fed, so depending on the capacity of the reservoir you’ll have to check it relatively often.
To refill your tank, put the water first, stir it if there was some nutrient solution left in your tank, check the EC and add more nutrients if necessary. Once you have the correct EC value, adjust the pH level of the solution and you’re done! Remember that the nutrient solution should be properly oxygenated and at around 20-22ºC.
If no pH or EC meters are used, plants will probably show nutrient deficiencies or excesses in a few days due to incorrect feeding parameters. So to speak, EC means the amount of nutrients provided, while pH means the way in these nutrients are absorbed (incorrect pH values will cause nutrient imbalances due to poor absorption, even if the amount of nutrients is correct).
In the case of non-recirculating systems, in which the irrigation water does not return to the water tank, pH and EC values are often more stable. Thus, in most cases you’ll only need pH and EC meters when refilling the reservoir of your nutrient solution.
Manual or portable EC meters are the most widely used in these cases. You get an instant reading of the desired value once the electrodes are submerged, so the batteries can easily last for months.
There are also devices that measure both pH and EC (some of them also temperature) with a single reading, so you know everything you need to know about your nutrient solution at a glance.
Is it difficult to use an EC meter?
No it’s not. As you’ve seen, you only have to submerge the electrodes to get an instant reading. The main advantage of knowing the exact EC of your nutrient solution is highly decreasing the risk of nutrient imbalances, so your plants can show their full potential, which means higher yields and quality.
While most feeding charts/schedules provided by nutrient manufacturers give you dosages in ml/l or ml/gallon – so you never know the exact amount of salts disolved in the nutrient solution – EC meters allow you to have full control over the feeding of your plants. Growers normally add all nutrients and additives until reaching an EC of 0,8-1,2 during the growth stage and 1,2-1,8 during the bloom period. Of course, these values may vary according to genetics, nutrients, water quality, etc. In both cases (growth/bloom) EC is gradually increased as plants develop.
In Alchimia you’ll find a wide range of both portable and continuous EC meters, we really recommend you to use these devices to achieve best results.