PH & EC meters
¿What's a pH meter?
Water pH express a range from 1 to 14 how acidic or alkaline a medium is. In this case a pH meter takes care of getting which is this pH showing it in a digital way, within a colartion of a sample of the liquid, or using test strips.
It is important to use a ph meter, because proper water pH can make a significant difference in plant's evolution (or in cases of aquariums it can affect fishes health).
¿What's an EC meter?
The EC of water express the electrocondutivity levels of it (or nutrient solution), what it is the water capacity of transmitting an electric current. EC values start at 0.0 (in pure water without any dissolved mineral) and rise as we add minerals to water. If we want to know the EC of our water , we need a digital EC meter, that will show in a digital numeric way the electroconductivity the sample has (so the amount of dissolved minerals in it).
An EC meter does not show which minerals are in water, it only shows a referral value of the total amount of dissolved salts. It is important to use a EC meter, as it is the only way to check and control the amount of nutrients we are sourcing our plants.
¿How does Ph and EC affect plant's health?
Ph takes a key role for a proper developement of plants. Checking the pH of the nutrient solution, and adjust it when needed, eases plants to quickly uptake nutrients sourced, turning into a more vigorous growth, and an abondant bloom, with an overall reinforced health.
If as a grower you ensure the water pH is the suitable you will be easing plant's work, that won't loose effords nor energy adapting the pH to its needings, what notoriously improves plant's speed developement and its health.
Same way EC of nutrient solution has a direct impact over plant's health. If EC of our water is lower than demanded by plants, these will show a lack of nutrients. If EC levels are higher than plant's demands they show symptoms of excess.
Knowing that an excess is way more difficult to solve than a lack (if you suffer a lack just add more amount of nutrients and solved, while an excess forces you to use enzyms, flushing and other techniques to solve the issue), it is always better to keep a low EC, than a high EC.
¿What types of pH and EC meters exist?
In the market there are many different meters: pH meters of water or growing medium, water EC meters and pH and EC meters. When we talk about water values measurements there are the following types:
Test strips for pH measurement
In a similar way it happens with reactive liquids, pH test strips react to a liquid changing the color. Depending on the color acquired we will know aproximatelly the pH value of that sample. It is a quick and cheap way to know more or less the pH values.
Liquid drops pH measurements
Ph kits using liquid drops are based in taking a sample from water to analyze and dropping a reactive liquid that will make water turn to a color. Depending on how acidic or alkaline the water is it will turn to a more red (acid) or blue (alkaline) color being a green color the neutral (ph=7).
Digital pH meters
Digital pH meters are the more precise way of measuring water pH, as they quickly show a precise value of the analyzed sample (unlike drops or strips that are aproximate)
The main advantage of a digital pH meter is that is much faster and easier to use. You only have to switch it on, submerge it in water and in few seconds it will show in its scree the pH of your nutrient solution.
Digital EC meters
Same it happens with digital pH meters, digital PPM meters are the more precise formula to check conductivity levels of water.
To use them it is only needed to put the EC probe in water and in few seconds the meter will give you an exact value of dissolved salts in water.
Ph and EC digital meters
As a grower you can acquire pH and EC meters separately, but there are brands that sell models that do both reasings with only one controller. These type of digital meters have two measuring probes, one for the pH and one for the EC, that are connected to the central unit of measurement, that usually shows both values instantly in the screen.
The main advantages of these combined systems are that continuous measurement probes are usually manufactured with higher standards so it's a better quality more precise. Also as they are constantly in water its lifespan is longer.
Ph values for grow and bloom stages
You must know that plants consume different nutrients in vegetative phase than in flowering stage. So water pH values should adapt to each stage of the growing cycle, to get plants to better and quickier uptake those minerals that will be highly consumed.
Ph for cannabis in vegetative stage
During growing stage cannabis consumes higehr amounts of Nitrogen. The nitrogen demand makes necessary to adjust water pH to improve the uptake of this element, so grower should adjust the pH in a value between 5,8 and 6,0 (in soil), or between 5,5 and 5,8 (in coco or hydroponic systems).
Ph for cannabis in flowering stage
Along bloom stage cannabis consumes mostly phosphorus and potassium. The demand of these two minerals makes necessary to adjust pH of nutrient solution to improve the uptake of both elements, so the grower should leave the pH value between 6,0 and 6,2 (in soil), and between 5,8 and 6,0 (in coco and hydroponics).
If you want to know more about recommended pH value for each stage of growth you can check our post in which we explain everything about recommended pH for cannabis growing.
EC values for vegetative and flowering stages
Cannabis EC is usually expressed in mS/cm (other units used are ppm, or parts per million) and can vary from 0,5-0,8 mS/cm and 1,8-2,0 mS/cm (understanding that not all strain will react exactly the same so only some strains will accept those maximum values of EC=1,8-2,0).
EC for cannabis in growing stage
The EC for growing stage depends mostly of the growing medium used (and the amount of nutrients contained in it). If your growing medium is low prefertilized, or non fertilized, it should be treated different than one that is highly prefertilized.
Our tip is to never use an EC higher than EC=0,8-1,0 mS/Cm in vegetative stage.
EC for cannabis cannabis in flowering stage
Along flowering stage of plants it is very important to check EC, because is during this phase of growth that plants are more likely to suffer from nutrient-locks and lacks of nutrients. Arrived to bloom stage, the only difference between soil and other growing mediums like coco or hydroponics are maximum recommended values of EC (in soil and coco it can be slightly superior than in hydroponics).
Our recommendation for Ec during flowering stage is to keep EC=1,0-1,6 mS/cm. If we begin flowering with an EC=1,0, and weekly increase that EC until arriving to EC=1,6 mS/Cm (last weeks of bloom) we can asure you the yields will be higher avoiding lacks and nutrient-locks.
If you want to know more about EC recommended values for each phase of the growing cycle you can check our post about recommended EC for cannabis.
¿When and how to calibrate a PH and EC tester?
Both, digital pH and EC meters, are precision instruments, so they require calibration every once in a while, to asure that values shown are correct, and avoid errors preparing nutrient solution.
We aim you to at least calibrate your testers minimum once per growth cycle, even though the ideal would be to calibrate them every month to avoid possible problems. It is also important to calibrate your tester if it has been stored for long time.
To calibrate your tester it is necessary to have a precise buffer solution. Some pH testers need to be calibrated using two calibrating points (so you need a buffer solution with pH 4 and a buffer solution with pH 7) while other more simple just calibrate with one point reference (in this case you should use a buffer solution with pH 7, which is the closer reading to cannabis likely values).
Another tip is to keep you tester clean. Always flush the probe with clean water after using to avoid any possible product attachments to the probe. If a long period has passed since you used your tester for the last time, we recommend you to put the probe in cleaning solution for 24 hours before calibrating the tester. After those 24 hours clean the probe with water and calibrate the unit.
If your tester works with batteries always remember that a low battery charge could cause errors in readings. If you have doubts about last time you changed batteries, it is better to replace the old ones and use new ones before calibrating the meter.
If you still have any doubt about how to calibrate a digital meter, do not hesitate to check our article in which we explain how to calibrate your pH tester.