Cultivating succulents can be either interesting or frustrating. For one, succulents are not very tolerable and do not permit trial and error in their cultivation.
In growing succulent plants, you either get it right or not. So, what soil is right for succulents? Do they like acidic soils?
Soil pH preference for succulents is quite variable. Most succulents grow best in slightly acidic soil, preferably with a high content of lime. They like soils with a pH of between 5.5 to 6.5. Cactus, for example, prefers a soil pH of 6. However, some succulents can also tolerate soil pH levels of even up to 7.0.
How to Make Soil Acidic for Succulents?
Highly alkaline soil can be made acidic through the process of acidification. If your soil is too alkaline, there are several methods to lower the pH. They include sphagnum peat, acidifying nitrogen, aluminum sulfate, organic mulches, elemental sulfur, and iron sulfate.
If you don’t reduce the alkalinity of the soil, your succulents may die because alkaline soil has a greater potential of killing plants than slightly acidic soil. Plants in alkaline soil will initially turn yellow, then become brown, and may eventually die off.
If your proposed planting site is small beds or garden areas, a good method to reduce the alkalinity is to add sphagnum peat. The pH generally ranges from 3.0 to 4.0.
It also adds organic matter to your soil. You add one or two inches of sphagnum peat and mix it into the uppermost 8 to 10 inches of the soil before you plant your succulents.
Elemental sulfur is the least expensive and safest method of lowering the pH of your soil. However, it is slow acting.
To prevent plant injury, you should ensure not to surpass 2 pounds of elemental sulfur for every 100 square feet for each application. You shouldn’t apply it more than once every three months.
Iron sulfate and aluminium sulfate are quicker in action than elemental sulfate. The only downside with this method is that iron sulfate and aluminium sulfate need to be applied about 5 to 6 times more.
Importantly, you should not apply any one of them over 5 pounds for every 100 square feet.
Furthermore, you can use some fertilizer types to acidify the soil, and they are safe. They include ammonium nitrate, ammonium sulfate, mono ammonium phosphate, urea, diammonium sulfate, and so on. You should read the label on the fertilizer sack to know if it is an acidifying type or not.
You can also reduce the alkalinity by watering the soil with a solution by mixing one tablespoon of white vinegar with five gallons of water.
If you are using this method, you should ensure that the top surface of the soil is dry. You can do this by covering the soil with gravel.
Another option for improving a highly alkaline soil is to water the soil with slightly acidified water. You add a little amount of citric acid or two drops of hydrochloric acid to the water.
Most soils are alkaline of the high content of lime, usually from the limestone material from where they were formed. Other times, it’s from irrigation with water having high pH.
In addition, if the soil is too acidic, with a pH of around 0.0 to 4.0, you should also make it slightly acidic so that the minimum pH requirement is met. You do this by adding some base or alkali to water and pouring it into the potting mixture.
I recommend making the pH of your potting soil slightly acidic because the effects of soil pH on plant growth are numerous.
The bacteria that act on organic matter releasing nitrogen in the process act best in a pH range of 5.5 to 7.0. Their activity becomes reduced by alterations besides this pH range, making nitrogen availability lesser.
Furthermore, most fertilizers act best in a pH range of 5.5 to 7.0. Therefore, having pH extremes on both the acidic and alkaline sides will negatively affect your fertilizing choice. In addition, soil aluminium becomes dissolved at soil pH levels of 5.0 and below, which is toxic to plant growth.
Soil pH levels also affect how much nutrients are available for your succulents. Nutrients are best available to plant when the pH range is between 5.5 to 7.0. Anything outside this, especially the extremes, means your plants won’t grow with the necessary nutrients.
Additionally, the soil structure is also affected by soil pH levels. If the soil is extremely acidic or alkaline, the soil becomes hard and sticky to cultivate. Therefore, it is pertinent to make your soil pH the desired one to grow your succulents.
Can Succulents Survive in any Soil?
Succulent plants will not survive in just any soil type. They are quite selective of the soil parameters they grow. So you should try as much as possible to be close to the best parameters to enjoy the best plant growth.
Regarding pH, they grow best in a soil of pH between 5.5 and 6.5, which is slightly acidic. So as much as possible, I recommend sticking with this value.
Despite this, if your soil is neutral, they’d still grow. Some can tolerate soil pH levels of even between 3.0 to 5.0, which is strongly acidic. Some species will also tolerate a soil pH of 8.0 to 10.0, which is strongly alkaline.
However, extremes of pH like 0.0 to 2.0 are extremely acidic, and they won’t grow. Likewise, a soil pH of 11.0 to 14.0 which is too alkaline.
Also, succulents are quite variable to the soil pH they prefer. For example, some succulent plants naturally grow on limestone soil which is alkaline in pH, and others in peaty soil, which is acidic.
Echeveria and some cacti from South America like Echinopsis and Gymnocalycium hate limestone soil. They naturally grow in peaty soil and shouldn’t be planted in compost soil with lime added.
Contrarily, some cacti from North America, like white-spined Escobarias, show a preference for limestone soil which is alkaline. Therefore, a little dolomite of lime can be grounded and added to the soil.
In addition, some other succulents are said to germinate on gypsum, which is neutral in terms of pH and has high calcium content. As you have seen, succulents have different tastes in the soil as regards pH levels.
Plants experience the best growth when planted in soil with a pH range that suits them the most. For this reason, you should not just go ahead and plant your succulents without testing the soil pH. It would help if you carried out soil pH testing using a soil test kit.
If you want to test the pH of your soil, you can obtain a simple pH meter in any gardening equipment store.
If you perform the test and the result shows that the soil is too acidic, you should neutralize it by adding horticultural lime to the soil. It reduces the soil acid levels to the level that your succulents will tolerate.
Further, the lime will alkalinize the soil, making it less acidic instead of overly acidic. A soil that is too acidic will adversely affect your plants and lead to delayed growth. They may even not germinate at all.
Soil pH is very important for succulent growth because succulents grow best in slightly acidic soil pH between 5.5 and 6.5. However, some may tolerate higher or lower pH levels.
But it would be best to avoid extremes of pH that are too acidic or too alkaline because they won’t grow. Therefore, test and adjust your soil before planting succulents.