In my last piece we looked at pH and how that can effect your plants. In this article we look at electrical conductivity (EC). This is the measure for how many mineral ions are present in your nutrient solution. An EC meter works by passing an electrical current through the water and calculating the resistance to the current. Its also possible to see the PPM (parts per million) of your solution if you are using a TDS meter (TDS stands for total dissolved solids). One is not better than the other, it is simply a question of what measurements are on your nutrient packaging. Be weary of companies trying to get you to use more nutrients by saying you need to use higher volumes of product than actually necessary: A good rule of thumb is to half the recommended volume.

It is possible to convert an EC reading to a PPM value using a simple mathematical equation. To get from EC to PPM you take your EC say for an example you have an EC of one then multiply it by a 1000. This of course equals 1000. Next divide by two. This leaves you with 500, which is your PPM value.

The reason that these measurements are so important to the health of your plants is that they measure how many nutrients are in a given solution. This is important as too high an EC will mean your plants will suffer from nutrient burns. Other things such as flavor and yield will also be impacted by overfeeding your plants.

It is also crucial to use filtered water, the best being reverse osmosis or RO water. Most city water already has particles in it, meaning that the water is not at absolute 0 ppm or EC. This will effect your plants as they will not get the maximum amount of nutrients that they can. Here in Europe, tap water is around 0.5 EC which means if you add nutrients and get your solution up to around an EC of 1.7, then you’ve only added 1.2 EC of nutrients. If your water was balanced out at 0 to start they would be getting the full 1.7.

Generally the prescribed levels that cannabis plants should fall into are between 1.2 and 2.0. The reality is, after much testing on my part, that the plants can uptake only so many nutrients. By feeding the plants more you are usually more guaranteed to burn them rather than to get massive fat buds. The best advice is to use your judgement and check the leaves, usually if there is a burn starting the very tips of the leaves will turn brown. If this happens don’t panic, just ease up on your next feeding or just give them water to give them a flush.

Keep on growing!

Any questions feel free to email