pH up and pH down Solutions used in Hydroponics and Aeroponics

Growing plants without the use of soil is made possible through hydroponics, only water mixed with a nutrient-rich water solution is used to provide all the essential nutrients and trace elements needed directly to the roots. Maintaining the appropriate pH level is a crucial aspect of hydroponic systems because it affects the availability and uptake of nutrients. To regulate the pH levels, pH up and pH down solutions are essential in hydroponics. In this article, we will explain what pH up and pH down solutions are made of and how they help plants grow properly.

The Importance of pH Balance in Hydroponics and Aeroponics

The acidity or alkalinity of a solution is known as the pH level. pH is measured on a scale from 0 to 14. A pH of 7 is considered as neutral, acidic if it is below 7, and alkaline if it is above 7. In hydroponic systems, maintaining the pH range between 5.5 and 6.5 is essential to ensure that the nutrients are accessed and absorbed properly. If the pH is too low or too high, the plants will not get the nutrients they need, which can lead to deficiencies, slowed development, and even death.

pH up and pH down Solutions:

To maintain the required pH range, hydroponic and aeroponic farmers use pH up and pH down solutions, which are made from strong acids or bases to change the pH levels effectively.

pH up Solution:

pH up solutions has strong bases that raise the pH level when added. The most commonly-used bases in pH up solutions are:

• Potassium Hydroxide (KOH)

• Potassium Hydroxide or KOH is an effective inorganic base that dissolves easily in water. Aside from helping raise the pH level, KOH also provides plants potassium, which is an essential mineral for healthy plant growth.

• Sodium Hydroxide (NaOH)

• Sodium Hydroxide, commonly known as caustic soda or lye, is another strong base used in pH up solutions. Unlike potassium hydroxide, sodium hydroxide is less popular even though it also effectively raises the pH levels. This is because sodium can build up in the nutrient solution and harm the plants.

pH down Solution:

pH down solutions has powerful acids that decrease the pH level when added. The most commonly-used acids in pH down solutions are:

• Phosphoric Acid (H3PO4): Due to its ability to lower pH levels, phosphoric acid is frequently used in pH down solutions. It also supplies the plants phosphorous, which is an essential nutrient. While it is effective, it can cause a nutrient imbalance if it is used excessively.

• Nitric Acid (HNO3): Nitric acid is another strong acid used in pH down solutions. Aside from adjusting the pH level, it also provides nitrogen to plants, which is an important nutrient for optimal growth. Nitric acid must be used carefully and in places with good air flow as it is corrosive.

• Sulfuric Acid (H2SO4): Sulfuric acid is highly effective in lowering pH levels. However, it is not commonly used in hydroponic systems because of its corrosive properties, which can damage plants.

At Agrotonomy, we treat our water through a reverse osmosis machine, rather than using pH up and pH down solutions. Using water that is free from chemicals allows us maintain the right pH level while having high quality fruits and vegetables and increasing crop yield. Across five (5) continents and over 30 countries, our team has found that using reverse osmosis-treated water (while not obligatory), greatly enhances our aeroponic farming projects.

Read the following articles to learn more about the reverse osmosis system that we use:

Operating a Tower Farm with a Reverse Osmosis System

Can you use tap water in a Tower Garden?