The Importance of pH in Hydroponic Systems

The Importance of pH in Hydroponic Systems

You may only consider pH to be a concept that you learn in a high school chemistry class, but it applies to gardening as well! Both soil-based gardens and hydroponic gardens rely on a balanced pH in the soil, or hydroponic nutrient solution. The soil’s pH fluctuates based on external factors and minerals around the garden, which may prevent you from growing certain types of plants. In a hydroponic garden, you’re entirely in control of the nutrient solution and its pH.

 

A successful hydroponic grower must know the importance of pH in hydroponic systems and cater to their plants’ specific needs, especially with tricky plants like blueberries. Once you master balancing the pH levels in your hydroponic garden, the list of what you can grow will expand even further.

 

The Basics of pH

 

When measuring pH, you use a 0-14 scale to determine how acidic or alkaline a liquid is. The lower the number, the more acidic it is; the higher the number, the more alkaline (or basic) it is. A liquid with neutral pH, such as pure water, will have a pH of 7.0. Typically, plants prefer to grow in slightly acidic environments, though there are some exceptions.

 

Outside, minerals and microorganisms regulate the pH—in your hydroponic garden, you may not have too many minerals and you won’t have any microorganisms. This leads to fluctuating pH levels that you must monitor regularly multiple times a day.

 

How pH Affects Your Plants

 

The pH levels affect different nutrients and their atomic structure in any given solution. With too high of a pH, plants may fail to absorb the changed forms of iron and calcium. Even if you have iron and calcium in your nutrient solution, if the solution is too alkaline, the iron and calcium will be in a form that is difficult for plants to absorb. Iron deficiency gives plants pale or yellow leaves, while calcium deficiency causes tip burn and leaf cupping.

 

With too low of a pH, you risk poisoning your plants with toxic levels of their essential nutrients. For example, plants may absorb a dangerous amount of the nutrient manganese at pH levels that are too acidic.

 

The pH Preferences of Different Plants

 

Because different nutrients become more available at different pH levels, plants in your hydroponic garden may have unique pH level preferences. As mentioned above, many plants enjoy a slightly acidic pH level between 5.5 and 6.0. Some prefer lower pH ranges, while very few plants prefer more alkaline pH ranges.

 

Some common pH ranges for fruits and vegetables are:

 

  • 5.5-6.0: Apples, tomatoes, melons, beans, squash, and most other crops.
  • 5.5-6.5: Most herbs.
  • 4.0-5.0: Blueberries.
  • 5.5-7.5: Pumpkins.
  • 6.0-7.0: Onions, peas, kale.
  • 6.5-7.0: Mint.

 

Whenever you plan to grow a new type of crop, research the preferred pH level that it thrives at before planting it. Use trustworthy sources and watch the health of your plants carefully—try marking their progress in a journal or chart.

 

You may also want to check the Electrical Conductivity (EC) of your solution and match it to the preferred EC of your plants. The pH and EC interact with each other, as a higher EC means that more nutrients have dissolved into the solution.

 

What Impacts Your pH Levels?

 

Your pH levels will naturally fluctuate over time, which is why it’s important to measure the pH levels multiple times in a day. Nutrients tend to be naturally acidic. As your plants absorb the water and nutrients from the hydroponic solution, the pH will rise as fewer nutrients remain. Too many nutrients in a solution will create too acidic of a hydroponic solution.

 

Other elements in a hydroponic system that impact your pH include the following:

 

Inorganic Grow Medium

 

Similar to how rocks and minerals behave outside, if you use gravel, clay, or rockwool as your grow medium, it will impact your pH at first. Lessen its impact by soaking it in a pH-neutralizing bath to match your ideal pH. Measure both the solution that drains out of the bottom of the hydroponic containers and the solution in the basin to see if it is a grow medium issue or a solution-based issue.

 

Algae and Root Rot

 

If you’re experiencing an algae problem in your hydroponic garden, your pH levels will reflect it. Algae takes in nutrients and carbon dioxide during your garden’s day cycle and is inactive during the night cycle. This results in high pH levels during the day, when the algae absorb carbon dioxide, and lowered pH levels during the night.

 

You can reduce the risk of algae by keeping your plants’ containers covered—at FloraFlex, we sell specialty tops with our grow kits that allow your plants to get the light they need while keeping algae out.

 

A sharp drop in pH may signify root rot or decomposing organic matter, such as pests. This requires your immediate attention before any disease can spread to other plants.

 

Testing the pH

 

There’s no harm in testing the pH of your solution multiple times a day, especially if you’re new to hydroponic gardening. Learning the importance of pH in hydroponic systems takes time and is difficult to master. Start by purchasing pH testing equipment from your local gardening or aquarium supplies shop.

 

You can use pH testing strips to get an approximate reading, or you can buy a digital pH tester for a more accurate reading. The digital scanner may cost more, but it’s worth it to see the exact pH of your solution!

 

Balancing the pH

 

When you need to balance the pH levels after accounting for the changes coming from the nutrients and your grow medium, use a “pH up” or “pH down” product intended for use in hydroponic gardens. Don’t try to add your own household acids or bases—you may unintentionally kill your plants. Make note of any additives you use in your growing journal to see how they affect the end result. Whenever you add anything to your garden, measure the pH frequently to monitor any drastic changes.

 

If you need more advice on how to adjust your pH or what pH is best for your hydroponic garden, join the blossoming community of FloraFlex growers and hydroponic supplies wholesale partners today! Our social media family can help you find the answers you need from experienced gardeners and suppliers.

 

The Importance of pH in Hydroponic Systems