Why is pH so important in a hydroponic garden?

pH – potential of hydrogen

pH is extremely important when growing plants because it directly affects the plants ability to absorb nutrients from the water.  In other words, keeping the pH in the right range enables your plants to absorb the correct amount of nitrogen, phosphorus, and potassium needed to grow and produce fruit.

Plants need both macro nutrients (nitrogen, phosphorus, potassium, magnesium, sulfur, calcium) and micro nutrients (zinc, boron, copper, iron, manganese). If the pH is too acidic, your plants will not be able to absorb the required amounts of macro nutrients and if the pH is too alkaline, micro nutrients will not be absorbed properly.

What pH should you aim for?

We recommend a pH of between 5.0 – 6.0 when growing most plants. The exact pH you should aim for will depend on what exactly you are growing. This article by the Oklahoma State University Extension offers a great chart on what pH different plants prefer when growing in a soil-less environment. For example, according to the chart, Pak Choi grows best in a water solution with a pH of 7, while most peppers prefer a lower pH of between 5.5-6.0.  

How and when should you monitor pH?

First, determine where you are going to get the water from to use for your hydroponic garden. All water, across the globe, will have a different starting pH. It’s a good idea to check your starting point pH (pH before adding nutrients to the water) by using pH test strips, pH test drops, or the easiest method, a pH digital meter. Try to use the same testing method each time you check your pH to maintain accuracy. When you first check your water source pH do not adjust the pH (by adding pH down or pH up) until after you have added the recommended dose of nutrients for the plants you are growing and the amount of water you are using per your specific set up. The pH of the water will be affected by adding nutrients and hydrogen peroxide so it is best to adjust the pH after, and then adjust accordingly.

Each time you add water (with or without nutrients) to your hydroponic garden, check and adjust the pH to the plants preferred level.

Things to keep in mind:

1. Group together plants with the same pH and nutrients requirements.

2. Add your nutrients and hydrogen peroxide first, then check and adjust your pH.

3. Check the pH of your water at least once a week even if you have not added any extra water or nutrients. Maintaining the correct pH can prevent your plants from getting sick from nutrient deficiencies. 

4. Use the same pH testing method each time you check your water, as this will help with accuracy.

Checking, maintaining, and learning about what pH specific plants need is the key to success in hydroponic gardening. Plants that are grown in soil rely on buffers such as microorganisms to maintain a healthy environment and pH. Plants that grow without soil rely on you to maintain their health. 

All Solaris Garden hydroponic systems come with a pH test kit and a bottle of pH down (most water sources have a high pH).

Thank you for your continued green interest.

Green Blessings,

The Solaris Team.

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