Impact of pH and EC on plants’ growth
An environment can be characterized by measuring its pH and electrical conductivity (EC). pH is based on hydrogen ion concentration and is a measurement of acidity in water or soil. EC measures the total amount of dissolved salts in a solution. Now that we’ve covered the boring definitions, let’s talk about something more interesting – how do pH and EC affect plants’ growth?
Maybe you are an experienced gardener that treats their plants as a part-time job or maybe you’re just looking for some more information on how to take of them the best way you can. Nonetheless, a basic understanding of the effect pH and EC have on plants’ growth is necessary.
A plant that is grown in soil is fed by all the microbes and even the soil itself, they create nutrients necessary for the plant to be healthy. If, however, you want to control that work of nature by a grower, you can grow hydroponically and take out the soil. Why should anyone do this? Read below and find out!
What is pH and how does it affect my plants?
The pH of the soil controls how much nutrients is available to the plant. It controls the form in which the elements are there for the plant to feed off. The nutrients need to be in a form which is water-soluble because it has to be able to get to the plants’ bloodstream and transported wherever it needs to go.
Every time pH is changed, the form and availability of the nutrients are changed as well. This can be for better or worse, meaning the availability can become better or worse. To make things interesting – different nutrients are available at different pH ranges.
In hydroponics, the ideal pH is anywhere from 5.8 to 6.2 while with soil it’s best that it’s a little higher, about 6.5. When the pH is in this range that plant has maximum availability of all necessary nutrients.
Different factors can affect the level of pH in your plants. For example:
- Alkalinity in the water – having too low alkalinity can decrease the level of pH
- Your choice of fertilizer – the ones which have a high amount of phosphorus or ammoniacal nitrogen will have an acidic reaction
- Plants roots – the older the root system, the more likely it is for the media pH to change
- Lime in the media – every time we water our plants we are adding lime to the media, which raises the pH level
pH testing kits can prove as a valuable tool for gardeners as they help with keeping the plants healthy. You will know where you are now with your pH level and that information is very valuable if you’re taking your plants’ health seriously.
Tests should be done every week and growers can even send their samples to a testing lab if they want to check whether their findings were correct or they need help with anything.
What is EC and how does it affect my plants?
Electrical Conductivity measures how well a solution conducts electricity. This is a function of the solutions electrolytes – which are charge-carrying particles. The more there are electrolytes the higher the EC. Basically, knowing your EC levels helps you with cost-efficiency when taking care of your plants and less shrinkage.
EC is a good measurement of how much salt is in the hydroponic reservoir. These salts are mineral salts that provide the plants the elements which they need and they are also used to create fertilizers. Unfortunately, EC won’t tell you what salts are in the solution and to get these information gardeners need to do a deeper analysis.
There are a number of factors that affect EC like:
- Water quality – good quality water should be less than 0.75 µmhos
- Fertilizer type – since fertilizers are created from salts, they seriously affect the EC level
- Watering technique – if you don’t water your plants regularly, they will build up salt at the bottom of the container which damages the roots
- Plant roots – the older the root system the fewer effect salts have and there is a higher chance of root rotting
- Environment – low light and high humidity cause the plant to stretch and become softer.
Neglecting some of these factors leads to a plant having nutrient deficiencies. The leaves then become yellow or very pale green, with the risk of never growing again. Also, you know something is not right if the leaf shape is different than usual.
The connection between EC and temperature is direct – with an increase of one Celsius, there is a two percent increase in electrical conductivity. The ideal temperature is found at around 25 degrees Celsius.
Plants like people, respond well to a moderate temperature when being watered. Imagine you’re being poured over with freezing cold or melting hot water, not a pleasant feeling is it?
There is a direct correlation between plants’ growth and EC. If you have a lower or higher level of fertilizer salts (EC < 1 or EC > 1) either way you’ll end up with plants with stunted growth and very bad health. The ideal EC range is between one and three milliSiemens per centimeter.
Some plants are more tolerant for salt than others. Be really careful about this since salt stress may lead to necrosis (death) of the roots or damage in leaves (color becoming yellow or leaves become veiny). If it happens that the plant is overfertilized and the EC is too high, immediately flush the substrate with a huge amount of water to remove the salt.
Measuring pH and EC
pH and EC affect plants growth so measuring them is key for a healthy plant. Once you have your results for the plants’ pH and EC level you should graph them weekly to see the trend in which they are moving. This way you can be ahead of the curve and act proactively instead of reactively to possible unwanted measures.
Are the numbers growing or are they declining? Is the trend line for media pH increasing or decreasing? Be careful when you take your samples. For instance, taking a sample two to four hours after feeding the plant will get you a higher EC result.
If you want to invest in equipment for measuring pH and EC know that this investment goes from 50 to 1000 dollars, so choose wisely based on your needs. The more expensive the more accurate the measurements are, but most people aren’t going to need such precision for them to take good care of their plants.
Addressing pH and EC problems
The usual issue is that high media pH is present, which causes leaves to turn yellow and tip abortion with lateral branching. Leaves turn yellow because of iron deficiency, and tip abortion is caused by a boron deficiency.
To address high media pH you can use more acid if you’re already using acidic injections, use an acid fertilizer (but be careful not to excessively grow your plants with this) or use a drench of iron sulfate.
On the other hand, lower levels of pH will cause stippling of leaves or marginal burn. Sometimes as a symptom the plant will have stunted growth as well. This happens because of calcium deficiency and the effects are serious as you can imagine.
To solve this issue avoid using acid injections and let high levels of alkalinity in the water raise the pH. You may also use a basic fertilizer, as they won’t cause excessive growth. Another solution to this issue is to use a drench of liquid lime.
High EC problems lead to excessive top growth or more root damages and rots. Avoid watering lightly to and make sure to water through the entire container. Use a lower level fertilizer until roots are more developed and then you can switch to a normal one.
If you wait for plant problems to show themselves first before you start to address them you are in trouble! Act proactively with your plants’ health and they will repay you by keeping your house looking fresh and your air clean.
Hopefully, this article has shed some light on the topic of the importance of keeping an eye out for this since we’ve covered how do pH and EC affect plants’ growth. Of course, the best way to learn something is to do it yourself, and then after that teach it to others. Remember, once you teach something to someone you get to learn it twice, and this is something every plant owner should know.
What are your experiences on this subject? Is there anything I didn’t cover that you would like to add? Do you see a difference in your plants’ health after starting to pay attention to their pH and EC levels? Let’s keep the discussion going in the comments below!