pH probes

In hydroponic gardening, where plants grow without soil, maintaining the correct pH (potential of hydrogen) level of the nutrient solution is not just important – it's absolutely critical for plant health and maximizing yields. The pH level directly influences the availability of essential nutrients to your plants, and a pH probe is the indispensable tool for monitoring this vital parameter.  In soil and other media, it is still important to keep up-to-date on what the pH is.  In these cases, you need to measure the runoff from watering your plants.  Long story short, the wrong pH can lead to all sorts of issues, most dominantly is nutrient lockout.  You can read more here.

Read my article on nutrient lockout here.