5 Facts Every Grower Should Know About pH

Data can tell growers a lot about their plants. For cultivators who use crop steering techniques, substrate and environmental data offer valuable insight that can lead to more informed decisions. But unless they understand the full picture of what they’re seeing, it’s tough to gauge which levers to pull and when. One of those levers is pH, a subject that comes up frequently on Office Hours – and it’s no wonder, considering pH plays a crucial role in a grower’s ability to achieve optimal plant health. In this article, we’ll explore 5 key facts cultivators should know about pH.

1. pH is about the balance between positive and negative ions in solution.

Alkalinity describes water’s ability to neutralize acid, and a substrate’s pH, or potential of hydrogen, measures the concentration of positive hydrogen ions in solution. At its core, pH signifies the equilibrium between positive and negative ions in the growing medium. The more positive ions in solution, the lower the pH; the fewer the positive ions, the higher the pH. 

2. pH is an indicator of nutrient availability.

The reason why pH in craft cultivation is so important to monitor is because it affects how the plant uptakes and metabolizes the different ions. Lower pH levels cause certain nutrients to be more available to the plant, and this shifts to a different set of available nutrients when pH levels are higher. Growers must work hard to find a happy medium because pH drifting out of balance is a signal that the plants are struggling to uptake nutrients, which can negatively impact plant health. 

3. pH and EC are not the same.

Where pH indicates the ratio of positively charged to negatively charged hydrogen ions in solution, that is different from EC (electrical conductivity), which refers to the level of positive and negative ions in solution. Put more simply, EC gauges the concentration of ions while pH indicates their balance. When working to achieve target EC, growers must also be prepared to monitor and make adjustments to ensure pH stays balanced.

4. Monitoring runoff helps growers prevent pH drift.

When pH drifts too low in the early growth stages, it can limit the amount of nitrogen, phosphorus, and potassium each plant receives. These essential elements become negative ions once they’ve disassociated from salts, and as the plant feeds at a healthy rate things shift to a positive charge in solution which causes that drop in pH. By monitoring and tracking runoff, growers can check incoming and outgoing pH as an indicator of which nutrients the plants are taking in – and what adjustments need to be made to maintain optional nutrient uptake.

5. pH varies by substrate and growth phase.

While a range between 5.6 to 6.0 is generally considered to be the pH sweet spot, pH management isn’t a one-size-fits-all journey. Different growing media and growth phases require different approaches to pH adjustment and maintenance. Finding a pH availability chart applicable to the grow medium they’re using is a great resource for growers looking for a reference point for optimal pH levels.

Conclusion

Getting a handle on pH is not only critical for growers striving to cultivate thriving, productive plants – it’s a crucial component of crop steering. Understanding its nuances, monitoring diligently, and adjusting accordingly gives growers even more control, allowing them to harness pH as they steer toward yield and quality outcomes. To dig more into pH, check out this crash course and Seth and Jason’s overview from Office Hours Episode 94!