A great benefit to using soil for marijuana growing instead of hydroponics systems is that soil plays the role of a buffering system for nutrients and water the plant receives. Therefore, if errors occur with the pH ratio or TDS nothing bad will happen immediately.
On the downside, nutrients build up in soil much easier, which can lower the pH level and raise the TDS levels. At the root, the pH and TDS amounts may vary greatly from the principles in the nutrient solution you give your plants. This could easily become a problem.
If you are growing in a Hydro system check out the article Rinsing Your Growing Medium and Why It’s Important.
Why measure your soil?
Additionally, there are other factors which can determine how the nutrients are being taken in by a growing plant. If it’s chilly in your grow room, the leaves of your plant won’t properly evaporate moisture because of the low temperature.
This evaporation is a key part of the vacuum cycle that draws nutrients up through the roots, and without it, your plant won’t pull in all the nutrients available in the soil. This means that the nutrients will start to accumulate in the soil, lowering the pH around the root system.
High acidity in the roots limits the intake functions of the root hairs, which further exacerbates the difficulty your plant will have absorbing nutrients.
This is an excellent example of how your plant’s environment can become unbalanced, even if the pH and TDS levels in your nutrient solution are perfect. It’s very important to measure pH and TDS of your soil regularly— every two weeks works well. And make sure to download my free marijuana grow bible for more tips & tricks
How to measure your soil
To measure the soil, begin by combining a 1:1 portion of the soil near the roots with demineralized water. Demineralized water which has a pH of 7 and a TDS of 0 and is available in any super market. At this point allow the mix to sit for about 24 hours and stir every once and a while. This ensures that all nutrients are totally dissolved. Now you can pour it through a filter, then use a meter to measure the pH and TDS levels.
The proper pH level will be close to 6 and the right TDS levels are from 750 ppm to 1500ppm, depending on the stage your plants are in.
If for any reason either the pH or the TDS levels aren’t right, you will need to increase the levels. Let’s says the pH is 5.5, you will have to use water that has a pH of 6.5 when your water your plant again. You will use this technique for TDS values as well.
Thanks for reading and make sure to check out my free marijuana grow bible for plenty of information that can help you grow quality bud.