" Ph and Nutrient Availability guide | Herbal House NZ

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Everything you need to know about PH and Nutrient Availability

As you already know (or should know!) there are 9 key essentials plants need in order to thrive. The most important are light, water, oxygen, nutrients and C02. We’ve spent a lot of time in our previous posts talking about lighting and photosynthesis, so today we’re going to focus on water and nutrients. 

Why does pH matter? 

When we talk about pH, we’re really talking about how acidic, or alkaline something is. And in the middle of that scale is neutral, which is typically around the 7.0 mark. The ph level of water for plants is 7.0, while acids are measured from 6-1 and alkali 8-14.

If you’re working with a hydroponic garden, understanding the basics of the pH scale is crucial. As you’ll be omitting soil which can help balance out pH, you’ll need to keep a closer eye on the pH of both the water, and nutrients you’re using. Otherwise you could quickly find yourself with damaged roots, pest infestations and dead plants.

What pH is best for hydroponics? 

The best pH for hydroponic plants is around 5.5-6.5, so you’ve got a little leeway. As you won’t be using soil, there’s already much less chance of your plants contracting diseases and pests like in traditional growing conditions. For extra protection however, a slightly acidic pH means that algae and other waterborne organisms will struggle to grow – meaning your plants won’t have to share their space or nutrients with anything else. 

Keeping your pH between 5.5 and 6.5 also prevents nutrient lockout, where your plants can no longer take up the nutrients they need. 

Ph level of water for plants? 

In one of our previous posts, we’ve highlighted all the nutrients plants need to grow. The pH of your nutrient reservoir affects how accessible these nutrients are for your plants. If the reservoir has a pH that is too high or low, your plants will lose their ability to absorb nutrients and completely shut down. Not ideal. 

The ideal pH level of water for most plants is generally between 6.0 and 7.0. it’s generally recommended to keep the pH at around 6.2 as this is the ‘sweet spot’ for hydroponics. However, this is a general recommendation, This range is slightly acidic to neutral, which allows for optimal nutrient uptake by the plants. However, it's important to note that different plants have specific preferences for pH levels, and some may thrive in slightly more acidic or alkaline conditions.

It's worth noting that when adjusting the pH of water, it's essential to do so gradually. Sudden, drastic changes in pH can shock or harm the plants. Additionally, some plants may have specific pH requirements, so it's beneficial to research the preferred pH range for the specific plant species you are cultivating.

how does ph affect plants

The pH level of water or soil significantly affects plants in various ways. It influences the availability of nutrients, as different pH levels affect nutrient solubility and uptake by plant roots.

Extreme pH levels can lead to nutrient toxicities or deficiencies, disrupting plant growth. pH also impacts the activity of beneficial soil microorganisms, which play a vital role in nutrient cycling and disease suppression.

Additionally, pH affects stomatal regulation, influencing gas exchange and water loss through transpiration highlighting the importance of ph in plants. Maintaining the appropriate pH level, usually slightly acidic to neutral, is crucial for optimal nutrient availability, uptake, and overall plant health, considering the specific pH preferences of different plant species.

pH buffers & nutrient availability ph

When buying liquid nutrients, most come with their own pH buffer, to make it easier for you to ensure your plants have the optimum levels for absorption. These buffers rebalance the pH of your water, making it a little bit easier to manage. However, you should still manually monitor the pH yourself. As your plants begin to take in water and nutrients, the pH can quickly fluctuate, so you’ll need to keep a pH testing kit to hand and some pH up and pH down in order to adjust to the correct pH value while maintaining the correct concentration of nutrients. 

So, that’s all you need to know for beginning your next hydroponics project!