Effect of Acidic and Alkaline Soil on Various Cacti

Cactus are succulent plants that are primarily found in the deserts of Africa. Most cacti species are known to do well in acidic soil and struggle to survive in pH greater than 8 or more. 

For cacti to flourish, the pH of the soil should typically range from 5 to 7.

Testing the water and soil for pH and making the appropriate adjustments are two ways to control it. There are numerous methods for measuring pH and adjusting it to the suitable range.

Besides discussing your choices for testing and adjusting pH in soil and water, this post will go into the significance of soil pH for cacti growth.

Cactus Prefer Acidic Medium 

Since cacti are considered acid-loving species, they thrive well in acidic soil mixtures.

That is to say, cacti would flourish in soil mixtures with a pH scale between 5 and 7. However, the preferred pH range can vary between different species. 

Expert horticulturists report that most cacti survive well in weakly acidic soil mixtures with a pH range of 5-6.5.

As a result, you should learn which pH level is suitable for growth before buying a cactus plant. It will help you choose the right potting mix and whether to nurture it in an indoor or outdoor environment.

The Significance of pH For Cacti

Because cacti like an acidic environment, their preferred pH ranges from 5 to 7.

While each variety of cactus has a specific pH range that it prefers, most thrive well between 5 and 6.5. 

The pH of tap water varies in areas, regions, and neighborhoods. So the more you water them, it’s likely you’re altering their pH.

Most areas have relatively alkaline water, which has a high pH. While you water your cacti without checking the water pH and regulating the soil’s pH, you put your plant at risk. 

The cactus may be unable to soak up the minerals required for growth and survival if the pH is above 8.

What Are the Signs That Cactus Is Going Through PH Imbalance?

A cactus with an imbalanced pH may exhibit signs resembling other problems, such as pest attack or sunburn.

It could have dark spots that appear to have received excessive light, yellowish discoloration on young shoots, or the plant will start shrinking from its overall size.

These problems arise due to particular soil components being more or less accessible because of the alterations in pH. Thus, the cactus needs to receive the proper proportions of the components it needs for growth. 

If there’s anything best to water your cactus plants, it’s rainwater. 

Rainwater maintains the ideal pH of the soil since it is inherently acidic.

To ensure the conditions are optimal for growth, it’s best to check the pH of water and soil. It will give you a fair chance to alter the pH of the water before you water your cactus plant. 

How to Measure the Soil’s pH

There are several pH indicators available on the market. Most of them are easy to use and give instant results.

For instance, a pH meter comes with a probe inserted in the soil and detects the pH while also indicating the moisture of the soil and light exposure.

It is helpful since it enables you to avoid under or over-watering and helps you to determine whether the cacti are receiving enough sunlight.

Another instant option is litmus paper. When touched on damp surfaces, it turns blue (for alkaline) or red (for acidic). 

Using a pH Meter

If you have a pH meter that also gives readings for moisture and light levels, here’s how to use it: 

  • Choose the three readings you want to take: pH, moisture, or lighting.
  • Insert the two probes around 3-5 inches into the soil. 
  • Adjust the meter’s position so the dial’s pointer is in constant motion. 
  • Leave the probes for 10 minutes and wait for the readings to appear. 
  • Once the reading appears, record it and carefully pull out the probes. Remember to properly clean the probes as it may affect the meter’s precision in subsequent use. 

Avoid forcing the probes of the pH meter in hard soil; you wouldn’t want to damage it. The pH meter does not work well on dry soil, so before you use it, it’s better to dampen the soil with light showers. 

Pure water or other fluids shouldn’t be tested with the pH meter. It can alter its default calibration. Also, remember that leaving the meters in the ground for a prolonged time might harm them. 

Checking the pH of Water

If you are a cactus parent, you need to have a pH testing kit for water with a soil pH meter. You have two options for checking the pH of water: a litmus paper or a pH water meter.

Since it offers a digital display, you can expect more precise readings from a pH water meter. When using litmus paper, however, you must observe the color changes of the paper and compare it with a litmus chart to determine the pH level. 

How to Use a pH Meter for Water

You can obtain the pH of water with the following steps: 

  • Switch on the meter. 
  • The testing probes in this device are the tips of the meter; dip them at least an inch deep.
  • Leave the tips submerged in water until the reading appears. 

The majority of instruments will be factory-precalibrated. But recalibration will be necessary if the meter has been used often or if it has been a while since you last used it.

Use deionized or distilled water to improve accuracy while recalibrating the instrument because they have neutral pH. 

How to Adjust the Acidity of Cactus Soil

When you have determined the pH of soil and water, you can easily adjust the acidity to meet your plant’s needs.

For a starter, it’s essential to check the water’s pH before giving it to the plant. This helps ensure that the plant is supplied with water in the optimal pH range and is not the reason for changes in pH. 

You can use several methods to control the pH of your soil when it’s on the alkaline side. You can apply sublimed sulphur on the top layer of the soil and let it leach. The pH will progressively drop as it gently percolates into the soil.

Using Aluminum Sulfate to Lower the pH of Soil

You may sprinkle aluminum sulphate into the soil’s top layer for a quicker response. The pH level at which you begin will determine how much aluminum sulphate you need.

Calculating the amount of acidic salts is crucial since excessive amounts can kill your cactus.

As a rough guideline, you can take 1.2 lbs for every 10 sq ft. Your purpose and choices will determine which chemical you choose. 

Using Lime to Raise Soil pH

Sometimes the soil pH can be too acidic for your plant to survive. In such a case, sprinkle agricultural lime on the top layer of the soil. 

Potassium carbonate can be used with water if you want instant results. Due to its high solubility, it quickly penetrates the roots.

In rare situations, you will only notice low pH, mainly when your soil is over-fertilized. It’s critical to have a good fertilization schedule. Before you plan to fertilize the soil, it’s best to check the pH. 

To regulate soil pH with water, it’s best first to check the pH of the water you plan to use. 

Using Water to Adjust the pH of Soil

The pH of rainwater is about 5.2. Therefore, you may maintain the soil’s pH at its ideal levels by bringing the water close to 5.2.

All you need is a water-soluble acidic chemical. While several chemical agents are available, synthetic vinegar is the most readily available. 

Why Is Alkaline Water Not Recommended for Cactus?

The Soil Will Gradually Become Basic

Only acidic environments are favorable for the cactus’s growth. However, they may thrive in unfavorable conditions due to their incredible adaptability. In alkaline environments, succulents may not survive for long. 

Important Nutrients Are Lost in Alkaline Soil

Iron and Magnesium, the two essential elements that succulents get from the soil, might become deficient due to the increased alkalinity of the soil.

These two components are crucial to their entire development and blossoming. In addition, deficits in phosphate and zinc can also be another problem. 

Effect on Root System

The development and growth of any plant depend highly on its root system. It supports the plant’s stature and provides nutrients, water, and oxygen for growth and development. 

An alkaline environment dries out the root system of cactus and eventually leads to plant death.

Wrap Up

In conclusion, acidic and alkaline soil can have a significant impact on cacti’ growth. Acidic soil can stunt the growth of cacti and lead to nutrient deficiencies, while alkaline soil can make cacti vulnerable to diseases and pests.

As such, it is important to choose the right soil for your cacti and maintain a proper pH level to ensure healthy growth. With the right soil and care, cacti can thrive, no matter what the pH level of the soil is.

Frequently Asked Questions (FAQs)

Do succulents like acidic fertilizer?

Succulents, when watered, will absorb moisture from the soil, so using fertilizer is not required for most plants. However, they can benefit from feeding using fertilizer.