How to Prepare Water for Hydroponics – pH, TDS, and PPM
If you’ve ever wondered how to prepare water properly for use in hydroponics in regards to pH, TDS, and ppm, this is the video for you. When preparing your water for hydroponics, always mix in your nutrients BEFORE you check and fix pH. You will see why in the video as the nutrients will affect your pH. Many people new to hydroponic growing get confused by the variety of terms and acronyms that are used to discuss nutrient strength and the various means used to calculate them so I will review this as well.
One big question growers ask is “Why are my plants suffering even though I used all the right nutrients, feeding cycles, my grow lights are good, and I adjusted temperatures & conditions to their absolute best?” That’s because their pH and PPM levels are off, making it difficult for their plants to eat. pH refers to the potential of Hydrogen ions in your water, which will determine if your water is too acidic or has too much alkaline in it. PPM (parts per million) refers to the concentration of minerals and soluble matter in your watering solution. Correct pH and PPM levels are the backbone of any grow room and will be the difference between a healthy harvest and a huge waste of time and money.
How to Prepare Water for Hydroponics – pH Levels
Simply put: the right pH level will create an environment where your plants can absorb nutrients quickly and easily, leading to a better harvest.
To prepare your water for hydroponics, nutrient-rich water is filled with elements that are helpful to your plants. However, if those elements can be broken down properly those same elements can harm your plants.pH levels are important to understand because the right level will determine the quality of helpful bacteria in your water that help break down elements, helping the metabolic rate of your plants. How? In two ways:
- When pH levels are too low (pH level of around 5 or lower), heavy metals like iron and aluminum change and can become toxic to your plants
- If the pH level is too high (pH level of around 6.5 or higher) elements like calcium and phosphorus can’t be broken down completely, which will hinder the growth of your plants
This change in properties is due to how acidic your water is or is not. You’ll want your plants’ nutrients to be a little acidic otherwise they can’t break down, but too much acidity and your nutrients can become toxic.
EC – Electrical conductivity
TDS – Total Dissolved Solids
PPM or Parts Per Million – A measure of TDS
TDS or PPM Meter – An electronic device used to test EC in a nutrient solution
How the meter works:
Most nutrients in a hydroponic fertilizer dissolve into ions that your plants can absorb and use to grow. Consequently, the ions in solution change the electrical conductivity of your nutrient. When you use a digital meter to check your nutrient strength, you are testing the EC of the water.
How to Prepare Water for Hydroponics – Why we use TDS at all
We as growers are generally not all that interested in EC by itself because the EC doesn’t really matter to the plant, all that matters is how much of the various nutrients are in the solution. Now I say EC isn’t important to the plant because many different ions will affect EC in different ways IE, one gram of Sodium Chloride (table salt) in one liter of water will have a different EC than one gram of Potassium Chloride in a liter of water. Also, some organic nutrients like green sand, blood/bone meal, and fish emulsion produce very little change in EC, but when broken down by soil bacteria can yield usable nutrients.
To try to mitigate this problem to some degree, most American TDS meters try to change EC to PPM. Converting EC to PPM is generally a very simple calculation involving a constant (either .5 or .7) multiplied by the EC in micro siemens. A quick aside, EC as reading on most meters, is in milliSiemens, very important to remember.
How to Prepare Water for Hydroponics – PPM Levels
PPM (Parts Per Million) refers to the concentration of the particulates in your feeding solution
When thinking about how to prepare your water for hydroponics, you must think of minerals found in tap water to natural elements found in your nutrients. your job is to make sure that the PPM levels in your watering solution are on point so you’re not under- or over-feeding your plants. While it’s an easy concept to understand on the surface, it’s a little more complicated when you have to adjust nutrient elements inside your grow room or grow tent.
For example, let’s say your plants need to be at a PPM level of 700. You mix your solution and you get a PPM reading of 700 but your pH is around 4.5. That means that the majority of the available food for your plants is likely to have lots of heavy metals in it, which will quickly toxify the plant. You’ll need to adjust the pH level of your solution to make sure you’re not toxifying your plants.“But won’t that throw my PPM levels off because you’re adding particles to your feeding solution?” It can, and that’s what’s so tricky about PPM and pH levels: When you adjust one you usually have to adjust the other, which can be simple or a huge pain depending on the water and nutrients you’re feeding your plants.
Adjusting pH Levels
Homemade pH Buffers
- Advantage: If pH levels are high you can use a little citric acid or even white vinegar to help bring your water’s pH down. When your pH levels are low you can use a little bit of baking soda in your solution and bring those readings back up. This will cost you less than picking up a buffering solution.
- Disadvantage: The issue with using these solutions is that they don’t work for very long. You’ll find yourself having to add a little lemon juice every other day, then having to use a little baking soda to even things out. Moreover, we’ve also heard of growers using these ingredients and seeing severe spikes in pH, which if not handled properly and quickly and bring plant growth to a halt.
Premade pH Buffers
- Advantage: Most hydroponic companies out there will have pH buffers, usually called pH Up & pH Down. They’re much easier to use than citric acid or white vinegar mixes. They’re designed to raise and lower the pH of your water while keeping your water’s pH levels balanced for longer than it would be without them.
- Disadvantage: As we’ve always mentioned, easier usually means more expensive. These solutions usually won’t cost you an arm and a leg, but they’re something you can’t simply make at home and will cost some money.
Be sure to check your pH levels because no matter how much you train your plants- like FIM’ing or using the Sea of Green method if your pH levels are left unchecked they will bring plant growth to a halt!
Adjusting PPM Levels
Before you start adjusting your PPM levels, you’ll first want to make sure your tap water is ready to feed your plants. That means you’ll want to adjust the PPM of your base water before you start feeding it to your plants.
- To rid your water of too many particles you can use things like a carbon filter or a reverse osmosis machine to clean your water. However, many growers agree that most tap water has helpful minerals (like calcium and magnesium) that help plants.
- During and after the vegging stage, your plants will want more out of their feedings so filtering isn’t really necessary. That’s why we recommend only using filters at the beginning of the plant’s life when low PPM readings are needed.
- Beware if your tap water has chlorine in it and follow the instructions in the video to fix.
- For a quick fix when PPM’s are high just add a bit of freshwater with a good pH level and watch them drop. Filtered, pH’ed water is great when things get a little too much in your reservoirs.
- When readings are low it’s usually time to feed your plants. When you add nutrients to your feeding solution your PPM’s will go back up, and when your PPM’s and pH’s are in balance your plants are going to be happy and healthy.
- Just remember that these readings need constant adjustment, so if you haven’t been keeping a close eye on your plant’s PPM and pH levels there’s no better time to start than now.
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Conclusion – How to Prepare Water For Hydroponics – pH, TDS, and ppm
Remember that when growing indoors, YOU are the one who controls all of the variables of the plant’s environment. Your lights, water, temperature, and humidity may be bang on but if your pH or TDS is off, things can go horribly wrong in the grow room!
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