> For the complete documentation index, see [llms.txt](https://faq.growsensor.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://faq.growsensor.co/substrate-probes/what-do-the-substrate-probes-measure.md).

# What do the substrate probes measure?

All of our supported substrate probes measure three key factors, giving you valuable insights into your root zone.

* **Water Content (VWC)** – Measures how much water is in your substrate, helping you fine-tune irrigation.
* **Electrical Conductivity (pwEC)** – Indicates the salt/nutrient concentration in your substrate, ensuring optimal feeding levels.
* **Substrate temperature** – Tracks how warm your substrate is, which affects root health and nutrient uptake.

### **Why is this important?**

Measuring Water Content and pwEC is essential for crop steering. It allows you to make data-driven decisions about when to water and when to feed your plants.

You can access dedicated graphs for each measurement in the Grow App, and set limits and alerts for all three to stay in complete control of your grow.


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