Peat Moss - How to Use Sphagnum Peat Moss in the Garden

Last Updated on October 31, 2021 by Phil

Peat moss or sphagnum peat moss is one of the most commonly used ingredients in potting mixes. This is thanks to its water and nutrient absorption and retention ability.

As such, it offers many uses in the garden from starting seeds to improving the quality of your soil. Similarly, many gardeners use it as an amendment to improve their flower beds and vegetable gardens.

However, because of how it is harvested, there is some debate regarding its environmental safety.

This article is a complete guide that will help you understand everything there is to know about peat moss.

Table of Contents

What Is Peat Moss?

Pest moss is a brown-colored, soil amendment that comes about from the decomposition of sphagnum moss and decays of other living things. It is harvested from peat bogs, where its fibrous texture is formed over a very long period of time.

You can think of it as a prolonged version of composting. But, unlike compost, the decomposition of sphagnum moss and other decaying organic material into peat moss happens without the presence of air.

This slows down the process of decomposition and creates a very absorbent material. The latter is one reason why peat moss is very valuable as part of potting soil in gardening. This feature also makes it a good amendment to soil and perfect for starting seeds.

Peat Moss vs. Sphagnum Moss: Are They the Same Thing?

One of the more confusing things for me when I was starting out was figuring out the difference between peat, peat moss and sphagnum moss.

So, in case there are some of you out there who have some questions regarding this, I’ll take a step back in this section to explain.

Peat vs. Peat Moss

Basically, in gardening, the word Peat is a broad term that defines different types of media that come about from decomposition of organic materials. Thus, there are many kinds of peat.

It is brown in color, has a soil-like composition and is harvested from bogs.

On the other hand, peat moss happens to be one kind of peat, albeit it is the most common type (coming from the sphagnum moss plant).

As such, both work very similarly. And, in many cases they’re used interchangeably.

That’s because, they both work well as soil amendments or organic mulch. Both are likewise acidic in nature so you can use them to lower pH that’s too alkaline.

Peat Moss vs. Sphagnum Moss

Like peat and peat moss are related, so are peat moss and sphagnum moss. That said, the two are also different.

Sphagnum moss in many cases refers to the living plant. There are a few hundreds species around and they are harvested for their horticultural uses.

Sphagnum moss is also something you’ll see sold in local nurseries and garden centers. It is green or green and brown in color and looks like moss.

It has a stringy texture to it. Although some stores will sell in chopped up. Many people use sphagnum moss to line hanging baskets because they help retain moisture.

What makes the two terms confusing is that peat moss is sometimes called sphagnum peat moss. And, while peat moss and sphagnum peat moss mean the same thing it makes it easy to confuse it with sphagnum moss.

From above, you already know that adding sphagnum in front of peat moss is just a way of specifying the kind of peat moss, meaning it came from the sphagnum moss plant.

While sphagnum moss is stringy and has a green and brown color, peat moss looks like soil. it is brown and has a similar texture and composition. But, it isn’t quite soil, instead it is used as a soil amendment.

Similarly, peat moss is dead and decayed plant matter coming from sphagnum moss plants. Over time, they end up settling at the bottom of moss bogs from where they are harvested for horticultural use.

Because the decaying period takes thousands of years, sphagnum peat moss will also include some other organic matter from other plants and animals as well in addition to that of the sphagnum moss.

These are the sterilized which makes it perfect for container plants. Its low pH (4.0), makes it a good choice for acid loving plants or if you need to bring down soil pH.

Peat moss also holds moisture while loosening up soil making it drain better. And, because it is inexpensive, many gardeners use it in combination with other substrates to create the right kind of potting mix for different plants.

Benefits of Peat Moss

Above, I mentioned a few of the reasons why peat moss is useful in gardening. But let’s delve a little deeper into the pros and cons of peat moss.

Here are the benefits of using peat moss.

Water absorption and retention – peat moss helps plants stay hydrated since it retains water better than most soil. it is able to absorb many times its weight in water allowing it to keep roots happy.
Is light and helps loosen up the soil to improve drainage – its light nature makes it drain excess moisture well and improve aeration. Plus, on your end, it makes it easier to carry the container in case you need to move its spot.
Does not get compacted – many substrates and soil get compacted over time. In doing so, they reduce the medium’s ability to absorb water. That’s not the case with peat moss as one application easily lasts for years without becoming compacted.
Sterile – this ensures that there are no pathogens, potential soil-borne diseases or weed seeds in the medium. Thus, you have peace of mind that none of these issues can eventually come to harm or kill your plant. This makes it safer than garden soil to use for houseplants.
Slightly acidic – this is both a pro and a con depending on what kind of plants you prefer to grow in your garden. as such, you’ll also see this entry in the list of disadvantages below. The low pH of peat moss makes it beneficial for acid loving plants which lets them absorb nutrients optimally.
Inexpensive – again, this falls into both a pro and a con. The reason being that if you don’t use a lot of it, peat moss is generally inexpensive. But, if you need to use a good amount, the cost will add up.

Drawbacks of Peat Moss

Can get costly if you need large amounts – in small amounts, peat moss is inexpensive. But, if you have an expansive garden or have big, large container plants, then the cost of the bags will start adding up.
Low in nutrients – peat moss don’t not contain much nutrients. As such, it does not contribute to the growth of your plant unlike compost or regular soil will.
Acidic nature is not ideal for some plants – it has a low pH around the 4.0 area which makes it ideal for acid loving plants. However, if you have other kinds of plants, the pH may be to low for optimal growth. Fortunately, this is easy to fix as you can modify pH to the ideal levels by incorporating garden lime.
Non-renewable – it is not sustainable. It takes hundreds to thousands of years for peat moss to be created in peat bogs. As such, harvesting is regulated by some countries to preserve them. This is why many environmentally conscious gardeners prefer using coco coir in place of peat moss.

How to Use Peat Moss in the Garden

Gardeners often use peat moss as:

An ingredient in potting soil – this lets you create your own potting mix for specific plants. In doing so, it allows you to provide each plant with the perfect environment for optimal growth. Creating your own potting mix also saves money compared to picking something that’s commercially produced.
A soil amendment – peat moss allows you to improve the quality and structure of soil in case the soil you have is not well suited for growing certain plants. It has an acid pH which makes it ideal for acid loving plants. Or, if you need to modify soil with pH that’s a bit too high (alkaline).

Peat moss works very well for both purposes because it is light and improves aeration. It also does not compact over time making it a better option to other substrates.

Just as importantly, peat moss doesn’t degrade or break down easily. So, you can apply it once and it will last for years.

Also, peat moss has been sterilized during processing. This lets you use it for potted plants and houseplants without fear that you might be introducing pathogens or weed seeds. Such is not the case for compost.

This is also why peat moss is used in place of garden soil for many houseplants. It allows you to use a soilless mix whereby eliminating the problems that come with regular soil. These include being heavy, not having the ideal kind of soil in your garden, poor drainage and the potential of having pathogens that can kill your plants.

That said, peat moss does not work well on its own as a potting medium. Thus, you need to combine it with other substrates to create potting soil.

Its ability to retain moisture and slowly release this moisture to the roots of plants makes it valuable in terms of plant growth. It is likewise able to retain nutrients.

Where to Buy Peat Moss

Peat moss is readily available in local nurseries and garden centers. Home Depot and Lowe’s also carry them which makes it very convenient to purchase some for your gardening needs.

If you don’t want to go get one physically, you can likewise order them online.

Prices will vary depending on the brand you get, where you buy it and the size of the bag you decide to pick up. I like to check out Amazon.com because they have good prices on a lot of gardening products, if they happen to carry the product.

If you have a small garden or are growing smaller container plants, you can go with the smaller bags that come by the quart. This is often enough for mixing your own potting mix.

If you need more of it, you can go get them by cubic foot.

Environmental Concerns of Peat Moss

One of the biggest concerns people have about using peat moss is that it is a non-renewable resource. Because it takes thousands of years for peat moss to turn into the end product that’s used in gardening, only very little is actually created on a yearly basis.

In addition, scientists argue that peat bogs are an essential part of our ecosystem since they absorb carbon dioxide. And, the decrease or eventual loss of these peat bogs from overharvesting will have negative effects on the environment.

This is why harvesting of peat bogs is regulated, in order to ensure that people don’t overdo it to the point that there’s nothing left in a few years’ time. At least this is the case for Canada were most of our peat moss is comes from.

Other countries don’t do as good a job in monitoring and preserving their reserves, with lax standards. So, to make up for this, some countries have banned the use of peat moss in order to curb its demand.

Peat Moss Alternatives

So what can I use in place of peat moss?

If you feel that the environmental concerns around peat moss makes it something not worth using, here are some alternatives you can use in its place.

Compost

Compost is one of the best alternatives to peat moss. And, it is a renewable resource.

if you’re making your own compost at home, you have the additional benefits of getting it for free while making use of scrap items. In the process, you reduce the amount of waste that you end up throwing in the landfill.

Compost is also a great addition to soil because it is rich in organic matter. This improves soil quality while increasing its ability to hold water.

Adding compost to soil also makes the soil lighter and improves aeration while contributing useful plant nutrients along the way.

The biggest downside to compost is that it may contain weed seeds. In contrast, peat moss is sterile ensuring no risk of pathogens or passing on diseases.

Perlite

Perlite is another option. Although it is very different from compost.

Like peat moss, perlite does not contain any nutrients. And, it is not something you’ll be making in your backyard.

Instead, it is made from volcanic rock that has been heated at high temperatures making them puff up. As such, they look like small pebbles or foam balls.

You can purchase perlite online or in your local nursery. They come by the bag.

Perlite is very useful as an ingredient for potting soil because it is able to retain water. It also keeps nutrients near the roots of the plant.

More importantly, adding perlite to potting mix improves drainage. This helps prevent overwatering or waterlogging which is the biggest reason houseplants die.

Additionally, perlite also improves aeration but allowing air to pass through easily thanks to its structure.

Vermiculite

Vermiculite is very similar to perlite. In fact, many gardeners will use one in place of the other.

That said, the two are not identical.

Once you see them up close you’ll instantly see the difference.

Perlite, as mentioned above, is made from volcanic glass that has been heated. When you open up the bag, you’ll see small white pebble-shaped particles. Other people describe them as foam-like.

On the other hand vermiculite is softer and looks like brownish small chunks of unrefined brown sugar (at least for the coarser ones). Finer grade vermiculite looks a bit more like brown sand.

Vermiculite is made from aluminum iron magnesium silicates that have been heated at very high temperatures. During this process it expands which is what allows it to absorb a lot of moisture.

In fact, vermiculite is able to absorb above 3 to 4 times it volume in water.

Similarly, vermiculite also improves nutrient retention which makes it beneficial for plant growth.

Its lightweight characteristic makes soil more airy as well.

Coconut Coir

Coconut coir or coco coir is made from the outer fibers of coconut shells. It is also a popular substrate and soil amendment that’s use in soil mixed.

The biggest benefit of coco coir is that it comes from coconuts. Thus, it is environmentally friendly since you’re using byproducts of coconuts which would otherwise be thrown away anyway.

Coconut coir helps make soil lighter and improves drainage. This has made it popular not only in soil gardening but also in hydroponics.

Final Verdict on Peat Moss

Peat moss is widely used in gardening for good reason. It provides many beneficial features when used to create potting mix or to improve soil.

However, the biggest concern about it is its non-sustainability. As such, some gardeners are shying away from using it, while others don’t mind at all.

That said, the balance between using this valuable gardening ingredient or going with an alternative is really up to you. There is no right or wrong.

Instead, it depends on how much you use and what it does for your garden.

Peat Moss – How to Use Sphagnum Peat Moss in the Garden