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Are pH testing strips effective for indoor Growing?

PH testing strips: Pros and Cons

As mentioned in our previous post, testing the pH of your growing soil and water is something to add to your weekly – or daily – to do list. While you’re used to tending to weeds or looking out for pests, checking on the pH of your soil is yet another thing you need to do regularly.

The pH will determine just how much nutrition your plants can absorb. If the pH of your soil or water is too acidic or alkaline, the plants will have a tough time. 

Why you should measure your growing medium pH

Whether you’re growing in soil or hydroponic solution, maintaining the optimal pH allows your plants access to all the nutrients they need. 

Each nutrient or element needed for plant growth has its own preferred pH range. As do different types of plants. When the pH creeps out of the optimal range, your plants may suffer from nutrient lockout. This ultimately could lead to nutrient deficiency or even a completely ruined crop. 

In terms of pH, the general sweet spot for hydroponics is a pH of around 5.8-6.5. For soil, the best pH is near enough neutral: At 6.5-7. For more specific rates, you’ll need to research the type of plant you’re wanting to grow. 

How to measure soil or water pH

One of the easiest ways to measure pH is with a pH testing strip (the name couldn’t be more obvious!) With these, you can dip the strip into a testing solution that is created with your growing medium. Like high school science experiments, the paper will then turn a different colour to represent the pH. When you purchase testing strips, they’ll likely come with a chart to help you identify what colour means what. As a general rule of thumb, reds, oranges and yellows are acidic, greens are neutral and blues or purples are alkaline.

Are pH testing strips effective? 

As with any equipment, there are always pros and cons. Below, we’ve taken a deep dive into the effectiveness of pH testing strips so you can decide whether to use them for yourself.

Pros

The most obvious benefit of these testing strips is that they’re super accessible, affordable and easy to use. 

Affordability is key if you’re going to be testing the pH weekly, if not daily. So pH testing strips are a great option for both beginner and expert growers. 

Another pro is that the results are pretty much instant. 

Cons

The major downside to generic pH testing strips is that they’re not specifically for growing. Therefore, their results are somewhat inaccurate. You might find that while the strips can give you a rough idea about the pH, they can’t give you a real, accurate reading. 

Another disadvantage is that strips are single use, so you’ll need to keep stocked up. You can’t re-use the strips so this could become quite costly over time. 

The third con to pH testing strips would be the need for good lighting. If you use quite a dark grow space, you will need to have access to a good light source almost as soon as you test for pH. This is so you can compare the colour of the strip to the manufacturer’s chart. Depending on the lighting, it could alter the way you see the colour – ultimately giving you a different reading altogether. 

Alternatives to pH strips 

Thankfully, if you’re looking for a re-usable, more accurate pH measuring tool, there are two options: Send your soil to a lab for testing, or use a digital pH meter. 

Obviously, sending soil samples to a lab is pretty pointless. As by the time you’ve got your results back, the pH will have no doubt changed! Plus, it can be incredibly expensive. 

A handheld, digital pH reader on the other hand, is a practical alternative to pH strips that provides an instant reading. All you have to do is place the tip of the probe into the soil, water or nutrient solution to get your results. 

While digital meters can be quite costly, they may work out a worthwhile investment if you’re planning to test pH every day. 

Regularly testing pH will allow you to make sure your plants are able to access all the nutrients they need, or to easily identify signs of stress in your plants before physical symptoms appear. Monitoring and regulating pH is no easy feat so if you're struggling with the process, or need a little advice, don’t hesitate to get in touch!