Cannabis plants need to be taken care of in order to grow strong and healthy. Over half of the work is making sure that you’re giving your plants high quality water, which is one of the most important and varied components when it comes to successfully growing cannabis. One of the main factors when it comes to water is its EC level, which should be at a certain level when it comes to growing healthy cannabis plants. Most people know that water can either be soft or hard, with or without minerals, treated, osmosis filtered and a plethora of options. In this post we’re going to talk about EC levels in the water you feed your plants.

What is EC? EC in Water

EC in Water when Feeding CannabisEC or Electrical Conductivity is the capacity that, in this case, liquids have of transporting electricity. Most people know that water can conduct electricity, although this is kind of not true. Water can conduct electricity on its own, this depends on the amount of minerals in the water. If it has lots of minerals, it can conduct electricity just like copper wire, however distilled water (H2O) won’t conduct anything.

Knowing the EC of your water allows you to estimate the amount of minerals that it contains, which in turn allows you to know if it’s good enough for your plants. Tap water, for example, has quite a large lime and sodium count, which makes for high EC levels.

EC levels need to be quite stable and in the right range for growing cannabis. The amount of nutrients in your plants’ soil and water is an incredibly important part of keeping your plants healthy, avoiding issues with deficiencies or accidental nutrient overdoses.

Bad EC levels in Cannabis Plants

Cannabis plants are quire sensitive when it comes to EC in water; this has nothing to do with electricity, but rather the amount of minerals in the water. The more nutrients and fertilizers used, the higher the EC levels which you can check using a simple EC meter. You may find that your plant is having issues absorbing water with plenty of nutrients; liquids with many nutrients are highly dense and won’t be able to filter through your plants’ roots properly.

High EC

The perfect EC for cannabis plants is pretty easy to figure out, and once you know it you’ll have a much easier time figuring out what’s wrong with them. If you find that your water has too high an EC, it’s like trying to filter milk through powdered cocoa in a coffee filter; if you put too much in, the milk will only be able to drip through, which isn’t ideal. EC levels are a crucial part of growing cannabis and making sure they can absorb the nutrients being given to them.

Low EC

If you find that your EC levels are too low, you’ll be forcing your plants to absorb more water, which causes them to expand in order to absorb even more nutrients. Plus, it’s super easy to recover a plant from low EC levels compared to one with high EC. In higher levels, plants’ roots can become entirely blocked and stop absorbing nutrients all together.

Cannabis can tolerate certain levels of EC and dense water. You can start off using distilled or osmosis water and then add certain nutrients in order to make the most of your substrate, so as to not stock it full of nutrients at the start. If you’re using tap water, your plants won’t be able to ingest the nutrients they need due to how dense the water itself is. This can cause nutritional deficiencies, as well as a large increase in minerals your plants can’t absorb, lime and sodium. This will eventually cause your plants’ roots to stop absorbing at all, eventually killing the plant if it isn’t corrected.

How to Adjust EC Water levels for Cannabis Plants

EC in Water when Feeding Cannabis

Speaking in general terms, the perfect EC level for cannabis plants is around 0.5-0.8 until around 13/15 days after germinating. This should be progressively increased to 1.1 towards the end of the growth period. During the bloom stage you’ll need to increase this, as your plants will need more nutrients. You should keep the EC between 1.2 and 1.5, keeping it there until the fattening period, where you should increase it to 1.8/2.1 – this is the highest it should ever be.

In order to increase EC levels all you have to do is add more nutrients to your solution or change it out for one with more nutrients in it. If you decide to use CO2 generators in your grow, you can increase the EC to 3.0, although this is fore massive, industrial yields.

One of the most common mistakes when it comes to new growers and EC levels is measuring the water used to feed your plants – you should also focus on the EC in your soil, which is where your plants are getting their nutrients from. In order to measure EC levels when growing in soil, as well as measuring your water, you should let some of it drain out and then measure the EC in that water – this allows you to know if the soil is too full of nutrients or not. Of course, if you’re growing hydroponically all you need to do is measure the EC level in the water.

EC Water Meters

Now that you know how deadly incorrect EC levels can be for cannabis plants, how to control it and why it matters, you can consider getting your hands on a precise EC meter.

EC meters are electric devices that have two parts; a sensor and an electrode. The electrode is used to calculate the conductivity in the liquid, extracting the EC reading as well as the temperature. Meters can also be continuous or portable, each with its own advantages, both as efficient ad reading EC levels. We highly recommend calibrating your meter before using it, and then after every reading so that there are no mistakes.

Portable meters are perfect for small growing rooms or soil grows, and they’re super easy to use – they don’t require much experience or previous knowledge of how they work. They’re incredibly precise and most of them measure water temperature as well as EC, giving you even more information about how your plants are doing.

Portable pH meter

When it comes to continuous meters, most of them can be attached to the wall or somewhere else handy. These meters are ideal for coco or hydroponic grows. All you have to do is submerge the sensor in the water and turn it on. These devices are 100% precise and we recommend calibrating them once a month. When kept clean and calibrated, these meters can last for quite a while.

Continuous EC meter

Hopefully this post has been able to help you decide on your EC water needs – it’s an incredibly important parameter that, alongside pH, can help you to know the exact quality of your cannabis plants. If you follow our advice and keep careful control over your plants’ water, they’ll grow strong and healthy! Until next time!

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Erik Collado

With more than 10 years of background in the cannabis sector, his experience and knowledge are the base of GB The Green Brand’s success

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12 replies on “EC in Water when Feeding Cannabis”

Hi James
EC measures the amount of dissolved solids in your water, once you’ve added all of the required nutes to your water, you can’t lower the EC without rendering the water nute-less. However, if you’re looking to lower the EC of your tap water for example, you can use a reverse osmosis filter.

Filter it out or dilute it with either distilled or RO water. I prefer to start with RO water and add the nutrients to it that I want, then adjust the pH.

You lower the EC by diluting the nutrient solution with clean water. Use water filtered with at least a single cylinder water filter but a reverse osmosis unit is ideal. If you need to lower the EC of your run off your are going to have to increase the amount you run through you rootball when watering.

You can flush the plants with distilled or reverse osmosis water that is pH balanced to help lower the EC

NEVER run plain R.O. water through the roots it pulls the nutrients out of the plants because water will flow in the direction of least nutrient which with R.O. water it’s the filtered water causing an osmotic reaction where the nutrients flow into the direction of the clean filtered water.

I read that H20 and Cal-Mag would lower EC. That didn’t happen using tap water. The EC levels went up. I’m going in circles.

The only way to reduce the EC is to add distilled water to the irrigation water. Using Cal-Mag the EC levels come up.

Kinds regards.

Your tap water is the culprit. Add distilled or RO water – not your tap water.

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