Cacti are some of the most resilient and hardy plants on earth, known for their ability to survive extreme climates. But, while cacti may be able to tolerate a wide range of living conditions, that does not mean they will grow happily in just any conditions.
Like any other plant, the cactus has its own set of ideal cultural care requirements which, when followed, will result in the growth of a thriving and healthy cactus. Factors that need to be considered when growing a cactus include light, water, temperature and humidity.
Another factor to take into account is the pH level of the soil you choose for your cactus. The ideal pH range for this plant is between 5.0 and 7.0.
It may seem like a daunting task to monitor the soil pH of all your cacti, but there are actually easy ways to do this.
In this article, we will discuss the importance of monitoring and maintaining the ideal soil and water pH for the growth of a cactus.
Why is it important to monitor the pH level of my cactus’ soil?
The ideal pH range for your cactus is between 5.0 and 7.0.
Different species of cactus have different preferences when it comes to this, but they will all likely be within that range. You should read about your specific cactus species in order to correctly determine the pH it prefers.
Also keep in mind that the soil’s pH can be affected by the pH of the water you are using for the plant. Cacti like soil that is more on the acidic side, while most tap water is usually more alkaline. So, if you use only tap water on your cactus, it should come as no surprise that the acidic pH of your soil will start to become more alkaline over time.
You need to be careful if the pH of the soil around your cactus reaches 8.0 or higher, because this can affect the plant’s ability to absorb its required nutrients from the soil.
How can I tell if there is a pH imbalance in my cactus’ soil?
When a cactus has a pH imbalance, it may exhibit symptoms similar to those of other problems, such as sunburn or a mite infestation. You may observe yellowing on new growth, brown spots on the plant’s skin that look like sun damage, or the plant itself may begin to shrivel and wither.
These signs appear because certain elements in the soil become more or less available depending on the soil’s pH level. As a result, the cactus may not receive the proper amounts of the elements it requires, hence the noticeable changes in the appearance of the cactus.
If possible, using rainwater on your plants is the best option. Rainwater is naturally acidic, and it will help keep the pH of the soil at its optimal level and decrease the chances of a pH imbalance.
You can also use a pH meter to monitor the soil or the water. Knowing the pH of your water allows you to make any necessary adjustments before giving it to your cacti.
How to monitor the pH level of the soil
The pH levels of soil indicate how acidic or alkaline your soil is. A pH of 7.0 is neutral, acidic soil has a pH value less than 7.0, while a pH value greater than 7.0 means that the soil is alkaline.
pH soil test kits can tell you the pH levels of your soil almost immediately. Testing is done by mixing small samples of soil with a chemical to see how the indicator dye changes color according to the acidity level.
Acidic soil causes the testing solution to turn orange-yellow, neutral soil causes it to turn green, and alkaline soil causes it to turn dark green. To determine the acidity level, you compare the resulting color with the chart that comes with the test kit, which looks a little like a paint swatch card. This is all of the information you require to determine whether or not you need to adjust the soil conditions.
You can also use a pH meter. Simply insert the metallic probe into the soil and read the pH directly from the digital display on the machine.
Although pH soil testing can be done at any time of year, it is best to do so within three months after application of lime, fertilizer or organic matter to the soil, so that enough time has passed and the machine can produce accurate results.
What do pH soil test results mean?
A pH reading between 3.0 and 5.0 indicates that the soil is extremely acidic. It is easy for plant nutrients to be washed away, leaving the soil deficient in trace elements. Lime should be added to raise the pH above 5.0.
A pH reading between 5.1 and 6.0 indicates that you have acidic soil. You can grow your cactus at this level, but if you are unsure, you can add more lime.
A pH reading between 6.1 and 7.0 indicates that your soil is ideal for growing a wide variety of plants, including cacti, because it is moderately acidic and densely packed with nutrients.
A pH reading between 7.1 and 8.0 indicates that your soil is alkaline, likely deficient in certain minerals such as phosphorus, iron, and manganese, and will require the addition of acidifying agents to correct its pH.
How to correct the soil pH level to suit your cactus’ requirements
Plants are unable to obtain their required nutrients from soil that is too acidic, but it is easy to alter the soil’s pH if you use the right combination of ingredients.
Lime can help to reduce acidity in the soil. Ground limestone is easy to spread, widely available at garden centers, and is the preferred method of repairing soil that has become too acidic over time.
If the soil is acidic, spread lime over the surface and work it into the soil to raise the pH and make it more alkaline. You will need to know your soil type in order to calculate how much lime to spread per square foot in order to bring the pH level down to the ideal figure of 6.5. As you add lime, continue monitoring the soil pH so you do not end up adding too much.
If the soil is alkaline, acidifying materials such as pine bark, compost, or sulphur can be added to lower the alkalinity of the soil while also improving its texture.
Cacti are some of the most resilient and hardy plants on earth, and have evolved to survive some of the most extreme living conditions.
Still, there are several factors you need to consider if you want your cactus to thrive. One of these factors is the pH of the soil you use for your plant. If the pH level of the soil is too high for it, this can leave it unable to absorb the nutrients that it needs from the soil.
The ideal pH level for a cactus is between 5.0 and 7.0, and you can measure and monitor this by using pH soil test kits or a pH soil tester.
Once you have determined the pH of the soil, and depending on whether it is too acidic or too alkaline, you can add the necessary substances to adjust it to the optimal pH of 6.5.
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