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What’s TDS and What Is It Good For?

Growing your own is easy, but like with anything else, it's important to get the lingo down. Things like PPM and TDS play an important role in your success.

What is PPM?

PPM stands for “parts per million”.

It means there's one part every million of nutrient/soluble/minerals in the water you feed to your plants. So, in relation to the actual volume of liquid, it's every 1 mg of minerals in every liter of water.

For example, distilled water can have a PPM as low as 0 and poor quality water can measure as high as 700. Generally, tap water clocks in at about 200-400 PPM. Controlling this number means you have a better chance of growing healthy plants.

Now, having a high PPM isn't necessarily a bad thing. A high PPM simply means you have a lot of minerals in your liquid. PPM is simply a unit of measurement and it’s used to measure TDS.

How do I measure TDS?

TDS stands for "total dissolved solids." It measures the content of substances in any liquid. Measuring the TDS in your water is crucial when you grow in a hydroponic system.

Why, you ask? Well, unlike soil-grown plants, plants grown in a hydroponic system get all of their nutrients from the water. In determining how high or low the TDS is, you'll know how many nutritious minerals are in your nutrient water. One way to measure is by using a TDS meter or an EC meter.

Why does TDS matter?

Having not enough nutrients for your plants is obviously a bad thing. They won't grow properly. But having too many nutrients can also be incredibly damaging. Your plants run into the risk of something called “root freeze”. When exposed to way too many nutrients, your plants' root system will shut down and stop absorbing nutrients altogether.

Knowing your TDS range will help you better control your plants. That’s why BC Northern Lights provides nutrient schedules. They take away any guesswork and ensure you’ll grow high-quality plants.

A quick tip for growers

A very common problem many growers encounter is getting inaccurate readings. We get calls all the time about TDS measurements appearing to be too high.

Here's an easy solution. Measure TDS in the water you plan on using for your grow box first. Jot down that number. Then, measure it again with the nutrients in. Subtract that amount from the first number you took. That's your actual TDS measurement.

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