pH and EC/TDS are two extremely important aspects of growing plants, whether you grow in soil or hydroponically. They are scientific scales that measure the acidity or alkalinity of a substance, and the electrical conductivity of a solution respectively. While that sounds a little bit intimidating at first, rest assured, as we can provide you with all of the basics that you need to know in this article, whether you are a beginner or advanced grower!
pH stands for Potential Hydrogen and tells you whether you have an acidic or alkaline substance. It is measured on a scale of 0.0 to 14.0, 0.0 being the strongest acid and 14.0 representing the strongest base, with 7.0 being the neutral midpoint. The reason pH is so important to monitor, is that all of the basic elements in your plant nutrients have a specific pH range in which they can be absorbed by the plant’s root system. Too low or too high, and you will lockout vital nutrition to your plant. If the pH swings extremely low or high, it can even outright kill the plant! Most plants prefer a slightly acidic nutrient solution and the method you use to grow also makes a difference. Plants in soil prefer their nutrients slightly higher between the 6.2 – 7.2 range while hydroponics and soilless mediums that provide constant access to a nutrient solution prefer things slightly lower at a range of 5.5 – 6.3. Keep in mind these are general ranges that fit MOST plants, but it is always a good idea to look up your specific plant’s preferred pH range to be sure. Regular monitoring of pH is recommended as environmental factors such as temperature, evaporation, and the normal process of the plant up taking nutrients will cause the pH value to fluctuate.
There are multiple methods that you can use to measure pH. The most inexpensive methods are to use pH test papers or liquid pH test solutions where you dip or take a sample of your nutrient solution and compare the resulting color changes to a chart on the product. We stock a very popular all in one pH Test Kit from General Hydroponics that includes the liquid test solution as well as the pH UP and pH Down solutions needed to adjust your pH to the desired level.
However, the test papers and liquids will only give you a rough range of where your pH potentially lies. If you want a truly accurate reading, you will want a digital pH meter. These meters work by utilizing a pH probe that measures the tiny amounts of electricity that are produced naturally by an acidic or alkaline solution. It is important to understand that the probes on pH meters are very delicate and perishable items, similar to a light bulb. They must be kept very clean, always wet after the first use (you can use calibration solution, storage solution or basic tap water, NEVER distilled or filtered RO water as they will damage the probe) and care must be taken not to break the probe. Just like a light bulb, their effectiveness will depreciate over time, and will occasionally need to be replaced. Most manufacturers warranty their probes for 6 months, although you can typically expect the life span of a probe to last roughly 12 months from first use, while the meters themselves typically have longer warranties, but will vary across brands and models. It is very important to find out the warranty requirements and procedures for your specific meter from your sales associate so that you are properly covered. We currently stock a wide range of pH meters from Milwaukee Instruments, pH meters from Hanna Instruments, and we have just been certified as an authorized dealer and maintenance provider for pH meters from Blue Lab!
EC stands for Electrical Conductivity and is the only way you can measure the TDS or Total Dissolved Solids in a solution. Pure water has no conductivity, but when nutrients or any particle is added to water, it dissolves salts and turns them into electricity conducting particles called ions. Measuring the EC/TDS level of your nutrients is how you know how much food is available to your plant. If it is too weak, your plants will be malnourished, while too high of a level will risk “burning out” your root system and potentially killing the plant. This is extremely important in hydroponic or soiless setups, as the plant is constantly exposed to your nutrient solution, and just like pH, evaporation and normal plant feeding will cause the value to fluctuate. You can adjust your EC/TDS level by either adding pure filtered water to lower the level (RO water is highly recommended, such as that produced by our Pure series of water filters), or by adding more of the appropriate nutrients that you are using.
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EC is the standard scale for most of the world, but in North America you will typically see TDS, which is measured in PPMs (parts per million), as the preferred scale. This can get a little tricky as there are 2 TDS scales in use, the PPM 500 scale and the PPM 700 scale. These scales are calculated by multiplying the EC reading by 500 or 700 respectively. When trying to match your EC/TDS level to your nutrient’s recommended level, be sure to double check which scale that particular nutrient company uses, as this will vary across brands. Most brands of digital EC/TDS meters will carry the option to measure in all of the 3 scales. Again we currently stock EC/TDS meters from Milwaukee, EC/TDS meters from Hanna and EC/TDS meters Blue Lab.
Both pH and EC/TDS meters require regular cleaning and maintenance to function properly. Occasionally you will need to calibrate your meter using standard reference solutions, such as pH 4.0, 7.0 and 10.0, and for EC/TDS, most brands of meters require a specific standard PPM solution to their brand. It is a good idea to get in the habit of calibrating your meters at least once every 30 days to assure their accuracy. As always, be sure to read your product manuals, review the warranty requirements and procedures, and if you need assistance, feel free to call us at HTG Supply Portland, and we will be happy to assist you with any questions!
Looking for Hydroponics in Maine? Looking for Grow Lights in Maine? Looking for organic gardening supplies in Maine? Come to HTGSupply in Portland Maine. We are the biggest and best grow shop in Maine. We have the largest inventory of Grow Lights in Maine, the largest inventory of hydroponic supplies in Maine and the best prices on all your indoor gardening supplies in Maine. We have the best prices on all the pH test equipment in Maine, including the best prices on pH meters from Blue Lab in Maine, and the best prices on Hanna Instruments pH Meters in Maine.