Can You Put Too Much Peat Moss in a Garden?

Peat moss is a substance that countless gardeners have used to manage the pH levels of their garden soil for their plants. Peat moss is undoubtedly popular and very effective in many cases—helping soil aeration and moisture retention and enhancing plant growth. However, as with most things, there is such a thing as too much peat moss.

You can put too much peat moss in a garden. Peat moss is very acidic, so if you’re trying to grow plants that don’t thrive in an acidic environment, too much might spell the end of your plants. Too much peat moss can also cause root suffocation in your plants.

The rest of this article will focus primarily on how much peat moss is too much and how much is necessary for most plants to grow. We’ll also discuss the advantages and disadvantages of peat moss and which plants aren’t big lovers of peat moss. By the end of this article, you’ll be a veritable peat moss expert!

What Happens if You Put Too Much Peat Moss in a Garden?

Let’s be honest: we all want our gardens to thrive. Buying additional elements to help your plants and flowers grow is not uncommon, and sometimes it’s indispensable. 

However, while peat moss can do wonders for your garden, in some circumstances, if you mix too much with your soil, you’ll end up with a poor soil environment—and in some cases, your carefully pruned plants might end up with suffocated roots.

Putting too much peat moss in a garden raises the acidity of your soil, so if you’re growing plants that aren’t huge fans of the stuff, they might not survive the onslaught. 

However, if you put too much peat moss in a garden full of acid-loving plants, it might not be too bad—as long as you rectify the situation by adding an alkaline substance that can alter the pH of the soil before the plant suffers too much damage. 

Plants with flowers also tend to be on the delicate side, so if you’re drowning them in high-acid peat moss, they may not fare too well. You might even kill them in the process. 

The rule of thumb is to add a little at a time. Too much might give you disastrous results, so go easy on the peat moss, and you—and your plants—should be fine. 

How Much Peat Moss Do You Require for a Garden?

Knowing how much peat moss is necessary for your garden provides the love and care your plants need. 

As a general rule of thumb—a 1:1 ratio of potting soil to peat moss should be adequate—depending on your particular plant’s requirements.

One of the most important things you’ll need to know about peat moss is that it works best when incorporated into the topsoil rather than mixed entirely into the soil. This depth requirement allows it to benefit the plants living in the ground but doesn’t change the nutrient levels of the soil depths, keeping the soil healthy and happy. 

For the best results, add around three inches to the topsoil and give it a little ruffle with your fingers to ensure it’s fully incorporated. As mentioned before, don’t dig it too deep into the soil—you should mix it just enough to cover the shallow parts. 

Benefits and Disadvantages of Using Peat Moss in Your Garden

As with many things, peat moss has several advantages and disadvantages. It’s essential to bear these in mind before applying it since it might prove difficult to alter the pH once it’s incorporated into the soil. 

Benefits of Peat Moss

  • Peat moss is like a sponge, absorbing water and keeping it in the soil. This high absorption means your soil will have elevated moisture levels for longer, so it can support the nutrients necessary for plant life. If you live in a dry climate and often water your garden, you won’t need to do it regularly if you use peat moss.
  • Peat moss lasts a long time. Since it doesn’t support organic matter the way soil does, it doesn’t go off, and you can easily reuse peat moss. Using it correctly could last you a couple of years—which may defray your initial expenses.  
  • There are no risks of your newly-bought peat moss bearing diseases or weeds. You reduce your risk because it is naturally sterile and doesn’t negatively affect the soil surroundings. It’s excellent for young plants since it gives you peace of mind that no pesky parasites are hanging around. Since peat moss is decomposed material, you can rest assured your peat moss won’t bring in unwanted diseases.
  • Peat moss doesn’t harden the way soil does when compressed. If you’re walking around your garden, it doesn’t flatten and become solid, so you don’t need to worry about fluffing it up with a trowel now and then. 

Disadvantages of Peat Moss

  • Peat moss can be expensive. Since harvesting peat moss requires a lot of work, you’ll likely find it’s one of the more expensive soil additions. 
  • Many discussions are taking place about the effects harvesting peat moss has on the planet. These concerns have revealed that the harvesting process is not sustainable and has implications for the environment and the wildlife who call peat bogs their home.

Peat bogs are home to a considerable amount of soil carbon, and the process of obtaining peat moss sets off carbon dioxide, ultimately accelerating the effects of climate change. Many countries are slowly banning peat moss harvesting, so if you’re looking for sustainable options for your garden, it’s best to try and find something else.

You should also consider the scarcity of peat moss—if you want to learn more, read my other article: Why is Peat Moss So Hard to Find?

Peat Moss Alternatives

Suppose you’ve given up on peat moss because of environmental concerns. If you’re a gardener, you know about sustainability and how it affects the environment—and the planet’s future. It’s essential to bear ecological factors in mind when caring for your garden, and using products that might harm the earth, in the long run, is a significant factor.

If this sounds like you, don’t fret! There is an alternative to peat moss that works particularly well —sulfur. Sulfur can give similar results to peat moss, and it’s more sustainable to produce. If you’re looking for a substance that can lower the pH of your soil, you’d be much better off with sulfur than peat moss. It’s also cheaper, so your pocket will thank you as well. 

What Plants Don’t Like Peat Moss?

As mentioned earlier, some plants aren’t big fans of peat moss. This aversion to the acidic miss is because they prefer a more alkaline environment—and adding peat moss makes their soil more acidic. 

Some plants who like alkaline environments—such as lettuce—will do fine with a little bit of acidity in their soil, as long as it’s not too much.

However, there are a few specific plants that may react to increased acidity, such as:

  • Cauliflower
  • Garlic
  • Radishes
  • Sweet pea 
  • Spinach
  • Kale 
  • Pole beans
  • Pumpkins

If you decide to use peat moss in soil that houses the above vegetables, go easy on the amount and try to keep tabs on the acid levels of the soil mix. This process will help determine whether you need a pH change along the road. You can buy soil pH kits easily from your local gardening center or Amazon.

For example, this Kensizer Soil Tester from will tell you precisely what pH your soil is. It can be used in outdoor settings and doesn’t need very long to find the results. Additionally, the meter can tell you how much moisture is in the soil. 

Does Adding Peat Moss Make Soil Acidic?

There is often some confusion surrounding this topic since many people think that peat moss doesn’t affect its environment as much as some say. However, that’s not the case.

Adding peat moss to your garden does make the soil acidic. It directly affects its environment, and the pH will ultimately lower. This effect can happen over several hours, so if you’ve accidentally applied peat moss somewhere you shouldn’t have, you may need to do damage control. 

However, it’s good to remember that soils containing limestone won’t bear the effects of peat moss as much as sandy soil. Knowing how acidic your soil is before applying peat moss will help you determine how much of an impact it will have on your garden and whether or not it is a good idea. 

Final Thoughts

Putting too much peat moss in a garden can have disastrous effects on your plant life and may not leave you with much choice other than to replant if you can’t re-alter the pH of your soil. Bearing in mind how acidic your soil is and your particular plant’s preference for acidity will help you decide if peat moss suits your needs.

If you’re looking for a more sustainable alternative to peat moss, it’s best to use sulfur. It will do the same job. Just remember that, like peat moss, it’s possible to use too much.

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

Recent Posts