Do Mums Like Acidic Soil? The Facts Explained

Mums are easy to grow and require relatively little maintenance and care. However, they still have their needs when it comes to growing up healthy and blooming beautifully. One important factor to pay attention to is soil quality and pH, which might leave you wondering: Do mums like acidic soil?

You can grow mums in soil with a pH of 6.0-8.0, which is slightly acidic to slightly alkaline. However, they prefer slightly acidic soil over alkaline or neutral soil. In practice, you should aim for a soil pH between 6.5-7.0 for the best results.

In this article, I will go over the ideal soil acidity for mums. I’ll also briefly explain the pH scale and detail the factors that influence soil acidity. I will also go over how you can check and adjust the pH of your soil for optimal health and growth.

Understanding the Ideal Acidity for Mums

The ideal soil acidity for mums is between 6.5 and 7.0. You can still grow them in soil with pH ranging from 6.0 to 8.0 without having a significant detrimental impact. Going outside of this range will potentially harm your mums, though, so it is important you remain within it.

Demystifying Soil pH

If you aren’t sure of what these numbers mean, here is a concise explanation to get you up to speed.

Essentially, 7.0 is neutral on the pH scale, and the scale itself ranges from 0 to 14. Soil (or pretty much anything else, for that matter) is neither acidic nor alkaline at the pH of 7.0. In scientific jargon, the concentration of hydrogen ions and hydroxide ions is equal at a pH of 7.0.

Fortunately, an understanding of how all that works is not important to our goal of having optimal soil pH. We only need to understand what pH is at a fundamental level.

The lower a substance goes under 7.0, the more acidic it is. Similarly, the greater the pH a substance has above 7.0, the more alkaline it is.

Another important thing to note is that this scale is not linear. Meaning the acidity or alkalinity increases exponentially as you near the extremes.

The Impact of Extreme Acidity or Alkalinity on Mums

Let’s discuss in more detail why you should stick within the 6.0-8.0 pH range with your mums and what the likely consequences of having soil that is outside that pH range would be.

The good news is this: in most cases, having soil pH that is too high or low won’t outright kill your mums. It will, however, have a noticeable and significant impact on their health, which certainly warrants your attention.

Having soil that is too alkaline or acidic makes it harder for your mums (and all plants, in general) to efficiently absorb nutrients from the soil, which they need to stay alive and grow healthily. A soil pH outside the acceptable range is likely to cause stunted growth in your mums.

It is common for plants planted in soil with too extreme of a pH (high or low) to have severe nutrient deficiencies, particularly when it comes to iron, magnesium, potassium, and calcium levels. 

Although you can somewhat combat these deficiencies with fertilizers (specifically organic fertilizers with high contents of the nutrients needed by plants), fertilization will not address the problem at its root cause. In turn, it is unlikely to be a long-term and effective fix.

You may also notice weaker, shorter blooms with fewer flowers. The flowers may also wither away, change color, and turn crisp. If they do, this is likely an indication of your mums having poor health. 

If your mums have changed color unexpectedly (for example, turning purple), it might be a cause for concern.

Interestingly, some plants adapt well to varied pH conditions. Fun fact: Hydrangea is a plant that blooms in different colors depending on the pH of the soil it is planted in.

Unfortunately, mums are not particularly resistant to the detrimental effects of extreme soil pHs. 

Soil Nutrient Deficiency

While nutrient deficiencies, and consequently, stunted growth, are commonly related to inappropriate soil pH, several other factors can cause stunted growth in your mums as well:

  • Inadequate sunlight
  • Low-quality soil with ineffective drainage
  • Poor maintenance and handling

You cannot say for sure that your soil has an improper pH based on stunted growth alone. However, poor growth can be a good indication, especially if you have accounted for and controlled for all other factors in your evaluation.

Factors Influencing Soil pH

Two of the more common factors that can affect soil acidity, especially in a setting such as a backyard garden, are rainfall and fertilizers.

I’ll discuss these factors in greater detail below.

There are other factors, such as the type of soil you have; for example, sandy soil tends to drop in pH more quickly from rainfall and organic decomposition. However, those are slightly less relevant to a garden setting.


This might be surprising, but rainfall is one of the major factors when it comes to determining soil acidity. When rainwater runs off across your soil, it takes with it basic ions. Essentially, these are the ions that act as a neutralizer or a counterpart to the particles that provide the soil with acidic properties.

When it takes the ions away, soil naturally becomes more acidic.

In addition, water from the rain may react with the CO2 in the air to form weak carbonic acid, which can add to acidity when it falls on your soil.

Unfortunately, this is just nature doing what it does best, and there is little you can do to prevent this from happening. You can, however, effectively remedy and adjust soil pH, as we will shortly discuss.


Certain fertilizers – especially the overuse of certain fertilizers, such as ammonium sulfate and ammonium nitrate – can make the soil more acidic over time. Nitrates are notorious for raising acidity when used in soil, as they tend to be very soluble and dissolve away, leaving behind the H+ ion.

It is best to be aware of the constituents of the fertilizers you intend to use so you will be able to predict what effects they will have on the pH of your soil. This way, you can make better decisions regarding their usage.

How to Measure the pH of Your Soil

To check the pH of your soil, you can use one of the easily commercially available soil pH detection kits. These can be brought online or in person at a gardening center or similar store.

These kits are easy to use, relatively reliable, convenient, and will offer you valuable information.

However, if you want an even more accurate, in-depth assessment of the pH of your soil, along with an analysis of other related factors, you can take a sample of your soil and send it to a local agricultural extension. It may officially be called something else in your locality, such as a state cooperative extension.

There are also ways to check for the pH using DIY techniques and ingredients. However, these do not yield as accurate of a result as the two methods stated above and are more for simply telling you whether your soil or acidic or alkaline instead of providing you with a precise pH.

That may not be enough to go off of when deciding exactly what you need to do to optimize the pH of your soil.

Correcting Soil for Plants

More often than not, if your soil does lie outside the acceptable range, it will be too acidic. To fight soil acidity, a calculated amount of limestone is most commonly used to neutralize the soil acidity and bring it to your desired pH range. 

Of course, the amount of limestone used depends upon the quantity and acidity of the soil to be treated. 

This is less common, but alkaline soil is typically neutralized with gypsum (calcium sulfate) or compost. Compost works because, as I mentioned before, the decomposition of organic matter increases soil acidity.

Final Thoughts

Mums do well when planted in soil with a pH range of 6.0 to 8.0; however, they prefer slightly acidic conditions. With this in mind, their ideal soil has a pH range of 6.5-7.0.

When planted in the soil outside this pH range, they start facing a decrease in their ability to efficiently collect vital, life-preserving nutrients. This will lead to nutrient deficiencies, overall lower quality of health, and potentially stunted growth and shorter lifespan.

Checking and remedying soil pH is straightforward and effective when done correctly.

Dr. Moritz Picot

Dr. Moritz Picot is a horticulture enthusiast and the founder of, where he serves as the lead content writer. He established the website in 2022 as a valuable resource for both gardening aficionados and beginners, compiling all the gardening tips he has accumulated over the past 25 years. Alex has a passion for nurturing plants, transforming backyards into inviting spaces, and sharing his knowledge with the world.

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