Peat moss is considered by many gardeners to be one of the most useful materials to add to a garden. If you’ve done much gardening at all, you’ve probably either heard of peat moss or used it without realizing.
Many seed starting and potting mixes have peat moss as an ingredient. You’ll also find it in big square bales for sale at your local garden center.
If you haven’t yet used this much-loved garden ingredient, you might be wondering: What is peat moss good for? Here’s more about peat moss, the pros and cons of using it, and when to use it in your garden.
What Is Peat Moss?
Peat moss is dead plant material that originates in peat bogs. It forms when layers of mosses and other organic materials decompose beneath the surface of bog water.
This makes peat moss a very unique garden material because it forms without the presence of oxygen. (Compost, for example, is broken down in the presence of oxygen and other elements.)
The decomposition process takes place over a long period of time: thousands of years, in fact. Eventually, all that decomposing plant material breaks down enough to form a soil known as peat.
Once it has reached a certain stage, the peat is harvested and dried out. It’s then formed into bales, which is the end product you see in gardening stores.
Peat moss is harvested from bogs like this one. The moss decomposes underwater without the presence of oxygen to form a unique material with many garden applications.
Most of the peat moss used and sold in the U.S. comes from bogs in Canada. A small fraction of it comes from Michigan.
Around the world, the biggest peat bogs are in Russia, Ireland, Scotland, Finland, Germany, and Sweden. However, due to the concerns of many countries about over-harvesting, the actual peat supply comes mostly from Russia and Canada.
Types of Peat Moss
There will always be slight variabilities in peat moss based on where it was harvested from and what the unique conditions of the bog were.
However, there are two main types of peat:
- Sphagnum peat moss– This is the most commonly used type of peat moss in gardening and what you will most likely find if you look for it at a garden center. Sphagnum moss is what grows at the surface of bogs. It breaks down to form peat soil that is easier to harvest and less decomposed than what would be found deeper in the bogs.After it’s harvested and dried, sphagnum peat moss is light in color and can retain 10-12 times its own weight in water. Don’t confuse sphagnum peat moss with sphagnum moss (although their names are very similar). Sphagnum moss refers to the plant material harvested when it’s still alive and growing above water. The end product is a light, fibrous material that’s often used to decoratively line wire baskets.
Although it has a similar name, sphagnum moss is much different than peat moss. It isn’t decomposed and is made up of long, fibrous strands. It’s often used to line hanging baskets like this one.
- Black peat moss– Although technically a type of sphagnum, black peat usually refers to older, more decomposed peat moss that is darker in color when dried. For garden use, the peat is allowed to freeze when wet to improve its water retention. However, it still only retains water at 4 times its own weight.The final product usually ends up being dark brown in color (rather than black) and with much finer particles than sphagnum. Black peat is most frequently used by commercial growers like mushroom producers in blends, rather than by the home gardener.
Besides types, there are also different grades available based on how fine or rough the particle sizes are. Horticulture grade (also called medium/coarse grade) is the most popular choice and what you’ll most often find for sale.
Coarse/chunk grade is another kind used by growers, mainly for camellias, bulbs, orchids, and for making well-aerated mixes for large containers.
Pros and Cons of Peat Moss
Before we get into the ways you can use peat moss in your garden, let’s take a look at why gardeners love it so much and what its drawbacks are.
- Water retention– One of the most sought after characteristics of peat moss is its ability to retain moisture and release it to plant roots. It holds water much better than normal soils, compost, and many other growing mediums. Even better, instead of getting soggy and causing root rot, peat moss is able to release water as needed to plants as long as it’s not completely saturated.
- Texture– Another great aspect of peat moss is the aeration it brings to soil and the fact that it doesn’t compact. Most soils compact easily, especially when walked on or after something like tilling disrupts the soil structure. (That’s why no dig gardening is a better option.) Compaction isn’t good for your plants because it hinders water and nutrient absorption. Peat moss, on the other hand, stays springy even when wet and won’t get compacted.
Peat moss can retain about 10x its weight in water. It then releases the water to plant roots as needed. This means less watering for you, saving you time, effort, and money.
- Sterile medium– A sterile growing medium is one that’s free of pathogens, insects, and weed seeds. Not all bacteria and microbes are bad, but using a sterile medium is preferable at times. For example, seedlings are most at risk for getting killed by pathogens because they’re so small. That’s why most growers use a sterile mix for starting seeds.
- Acidity– Sphagnum peat moss ranges from slightly acidic to a pH around 4.4. This makes it an ideal medium for acid-loving plants.
- Low fertility– Peat moss is excellent at holding nutrients in the soil, but it doesn’t have much nutrient value on its own. At best, it will have trace nutrients, so it’s not a good choice for feeding your plants.
- Cost– For small applications, the cost of peat moss isn’t likely to dent your wallet very much. However, any large scale use of it (like amending a whole garden area) can get pretty expensive.
- Acidity– You’ve probably noticed that this is listed in the ‘pros’ section as well. That’s because the acidity of peat moss can be either a positive or a negative depending on what you’re using it for. In this case, if you grow plants that need a neutral or alkaline soil, the acidity of peat moss is a drawback.
- Nonrenewable resource– The biggest drawback by far of using peat moss is that it’s considered a nonrenewable resource. Technically, peat bogs do grow back but at a rate that can be as low as 1/16th of an inch per year.Canada is the only country that has taken steps as a peat moss supplier to conserve peat bogs. They allow only about .02% of their supply to be harvested every year. Other countries, like Scotland, have designated most or all of their peat bogs as protected and not to be harvested.
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- Environmental concerns– The actual harvesting process for peat moss is also under scrutiny. The bogs are drained of surface water, and layers of native vegetation are removed to get at the peat. Once it dries out enough, peat moss is essentially vacuumed up at rates of about 100 acres per day.
The main environmental concerns are habitat destruction for animals and plants living in the bog (including unique species of frogs and vegetation) and upset of delicate ecosystem balance. Once again, Canada has done the best job of finding more sustainable harvesting methods and working for bog restoration.
What is Peat Moss Good For?
Most gardeners agree that there is nothing quite like peat moss when it comes to certain garden uses. Here are the top ways to consider using it in your garden.
Make Your Soil More Acidic
It’s no secret that peat moss is one of the easiest and quickest ways to make your soil more acidic for acid-loving plants like blueberries, camellias, azaleas, and blue hydrangeas.
There are other ways to lower the pH of your soil, but they either take much longer (elemental sulfur) or can lead to a buildup of heavy metals in your soil (iron sulfate).
Adding peat moss into the soil where you’re planting will immediately lower the pH. Even better, one application of it will last for several years, and it’s easy to reapply.
Hydrangeas need acidic soil to produce blue flowers. Alkaline soils will turn flowers pink. If you have a hydrangea bush that you want to be blue, peat moss is an easy soil amendment to increase acidity.
To make your soil more acidic with peat moss, spread out a 2-3 inch layer of it over the soil area where you’ll be planting. Then, work it down into the soil with a shovel or garden fork to a depth of about 12 inches.
Make sure you water the peat moss thoroughly until it looks and feels wet. Dry peat moss will end up taking moisture away from your plants, but it will retain water for a long time once wet.
Seed Starting Mix
Because it’s sterile and absorbent, peat moss makes a great ingredient in any seed starting mix. You’ll find it in many commercial seed mixes, and you can also use it to make your own mix.
You shouldn’t use peat moss alone as a seed starter. Start with it as your base ingredient and add an aerating ingredient like perlite or vermiculite. You can also add a tiny amount of fertilizer to feed your seedlings once they start growing.
Other optional ingredients include lime (to balance out the pH), coconut coir, and beneficial mycorrhizae (helps your plants to root).
One question many beginner gardeners have is what’s the difference between seed starting mix and potting soil?
Peat moss is a common base ingredient in both seed starting mixes and potting soil. You can easily make your own mixes by adding other ingredients like perlite, vermiculite, compost, fertilizer, etc.
Seed starter mixes are usually more lightweight than potting soil and have low to no nutrients. They are optimized to get your seeds started and allow your seedlings to easily put down roots. Most seed mixes are sterile to prevent bacteria and other pathogens from killing your seedlings.
Potting mixes are usually heavier and more fertile because they are designed to support larger, growing plants. They can be sterile but many aren’t.
Peat moss makes a great addition to store-bought and DIY potting soil. It helps soil hold onto moisture for longer, which is especially great for container gardens, while still keeping the soil well-drained and aerated.
It also holds onto nutrients that might otherwise be washed out of containers when you water your plants.
Use peat moss as ⅓ – ⅔ of your total potting soil mix. The rest can be mainly compost or store-bought soil with perlite and some type of fertilizer added in. If you are growing plants that need a neutral to alkaline pH, add in some lime to balance out the peat moss.
Amend Your Garden Soil
Peat moss has characteristics that make it excellent at amending both heavy clay and sandy soils.
If you’re trying to grow in either heavy clay or sandy soil, peat moss is one possible amendment to improve soil texture and drainage. Keep in mind that many vegetables and common garden plants prefer a neutral or slightly alkaline soil, so you may need to balance out the pH with lime.
The light, aerated texture of peat moss will help to lighten clay soils. It’s especially useful for amending clay soils that have been compacted and can help to prevent compaction in the future.
Peat moss will also improve drainage, which is often a problem in clay soil.
For sandy soils, amending with peat moss will give your soil better water and nutrient retention. Nutrients tend to leach out of sandy soil, especially with lots of rainfall, and that’s something amending can fix.
To amend with peat moss, spread it out over the area you want to amend and work it in to a depth of 12 inches. If you don’t want to lower the pH of your soil, mix in limestone at the same time.
One of the more recent uses of peat moss in the garden is to make biodegradable pots for seed starting.
You can buy these pots online or at your local garden center. While most seeds are more easily started in flats or cell packs, plants that hate having their roots disturbed are best started by seed in these pots.
The pots get planted in the ground with your seedlings whenever it’s time to plant. They naturally degrade and break apart as time goes on, eventually becoming a part of the soil.
A few tips about peat pots will make your life a lot easier when using them.
Biodegradable peat pots were a great invention in the gardening world. They allow you to plant seedlings without disturbing their root systems, which is great for plants that don’t transplant well.
Before adding your seed starting mix to the pots, get them wet by soaking them in water for 1-2 minutes. When you water your seedlings after they sprout, water the pots at the same time to keep them from drying out because dry pots will wick water away from your plants.
When you go to plant the pots, break off the rim of each one so that it’s level with the soil your seedling is growing in. Make sure no part of the peat pot is sticking out of the soil after planting or it will act as a wick to take water away from plant roots.
Normally, you wouldn’t use peat moss as a mulch. Regular mulch is more cost effective, and it would be a waste to use something nonrenewable like peat moss on a large area.
However, you can mulch with it around your acid-loving plants (azaleas, rhododendrons, blueberries, cranberries, gooseberries, camellias, gardenias, magnolias).
Doing this will not only help to keep moisture in the soil and keep weeds down, it will also help to keep the pH from creeping back up over time. A nice mulch with peat moss every year or two will keep the acidity of your soil where you want it without much trouble.
Alternatives to Peat Moss
If you feel concerned about the environmental impact of harvesting peat moss, there are some alternatives out there, although none have exactly the same characteristics.
For certain applications, compost can be a good alternative to peat moss. You can easily make compost yourself by using bins like these ones, and there are also more compact options available for smaller spaces.
Here’s a look at the top three.
If you want to amend your soil without lowering pH, compost will almost always do the trick.
It’s easy to make compost at home, and it will give your soil better drainage and texture. Compost also provides a lot of nutrients to soil, something that peat moss doesn’t do.
An easy method for amending or fertilizing with compost is to apply it to your garden beds in late fall. The winter weather will help to break it down and incorporate it into your soil, saving you a lot of effort in the spring.
Keep in mind that this is not a good option if you want to acidify your soil, and it compacts much more easily than peat moss.
Coconut coir is a fairly new addition to the gardening world and is often marketed as an eco-friendly alternative to peat moss.
It retains water, lightens soils, and adds better drainage. You can use it in place of peat moss as part of a seed starting or potting mix. It’s also a very renewable resource since it comes from the husks of coconuts.
Coco coir comes from the husks of coconuts. It used to be a waste product that was discarded after the meat of the coconut was taken out, but it was discovered to have many useful attributes for gardening.
The downside is that coconut coir is just as or more expensive than peat moss, so it’s not cost effective for large projects. It also won’t change the pH of soil, which can either be a plus or a minus.
Biodegradable peat pots are a huge hit in the gardening industry. However, some companies are coming up biodegradable options that aren’t made out of peat.
One of the most prominent options so far is called CowPots. They are made from composted cow manure and are completely biodegradable and renewable, plus odor-free!
CowPots may cost you a little more than peat pots, but that little bit extra is worth it for many gardeners.
Using Peat Moss Sustainably
Peat moss remains a unique gardening material with characteristics that no other medium has. In many situations, there’s just no substitute for it.
In your own garden, the best way to use peat moss sustainably is to reserve it for applications where there is no good alternative and to use it only for small scale projects as much as possible.
If you have a bag of peat moss on hand, why not use it to make your own seed mix or to try growing acid-loving gardenias indoors?
What is peat moss used for in gardening? ›
Uses for peat moss
Potting mixes: Peat moss is the main ingredient in many potting soils because it helps so much with drainage. Plants in containers often have problems with waterlogged soil, which peat moss helps prevent. Seed starting: Because it's sterile, peat moss is one of the best seed-starting mediums.
Peat moss should be mixed into soil. Top dressing with peat is a bad idea because wind will blow it around and rain will harden it. — Mulch nourishes the soil as it breaks down. When well-incorporated into soil, peat can aid nutrient availability, but it contains little or no nutrients of its own.Is peat moss good for garden beds? ›
Peat moss is used to add structure and water holding capacity to your raised beds. Oddly it both promotes great drainage and holds water that plant roots can access as needed. Peat moss has a rather wide quality range and using the best quality peat moss you can afford is recommended.What are three uses of peat moss? ›
Peat moss's principle benefits are its water retention property, improvement in soil texture, and its ability to help keep nutrients from leaching out of the surrounding earth.What plants should you use peat moss? ›
Peat moss is acidic, and is excellent for use with acid-loving plants, like blueberries, azaleas and tomatoes. Because it can make your soil more acidic, you may need to add lime to the soil.How long does it take for peat moss to break down in soil? ›
It doesn't really decompose because peat moss is so anaerobic and this process takes very slowly. The decomposition process happens without the presence of air, which slows the development rate. It only gains less than one millimeter in depth each year. One day, the producers show up.Do I need to mix peat moss with soil? ›
Since peat moss is acidic, it has the effect of reducing pH levels in alkaline soils. If a soil test indicates that your soil is too alkaline, mixing in some peat moss will help bring it down.Is peat moss better than mulch? ›
Mulch nourishes the soil as it breaks down. When well-incorporated into soil, peat can aid nutrient availability, but it contains little or no nutrients of its own. Mulch is superior to peat moss at suppressing weeds. Mulch is usually made from local hardwoods and doesn't travel far.Will flowers grow in peat moss? ›
Almost any potted plant you can buy grows in a soil mix that contains peat moss, and most bagged potting soil does as well. You can also buy it on its own to mix into your own potting soil blend. It's especially useful for growing flowers and food in containers, because it helps plants maintain the moisture they need.Should I put peat moss in my vegetable garden? ›
In the vegetable garden, peat moss can moderate extremes in soil dryness and wetness. This is particularly important when growing juicy-fruited plants with tender skins, such as tomatoes, strawberries and blueberries.
Can you put too much peat moss in garden? ›
what will happen with too much peat? The excess peat will take up space from the compost/nutrients. Adding compost without removing the peat will spill over the boxes before it gets to the correct amount.When should I use peat moss? ›
Great for plants that need acidic soil: Gardeners often use peat moss to manage soil pH. When planting species that thrive in acidic soil—such as blueberries or azaleas—mix peat moss into your potting soil to achieve an acidic pH. Peat moss can also help neutralize alkaline soil by bringing down the overall pH.What vegetables don't like peat moss? ›
Plants that prefer more alkaline soil don't do well with peat moss. These include cauliflower, garlic, asparagus, spinach, many gourds, and others. Peat moss's problem is that it is acidic, and as your soil's pH level gets lower (meaning the soil becomes more acidic), vegetables like these begin faring poorly.How long does peat moss last? ›
Since it doesn't compact or break down readily, one application of peat moss lasts for several years. Peat moss doesn't contain harmful microorganisms or weed seeds that you may find in poorly processed compost. Peat moss is an important component of most potting soils and seed starting mediums.How long does it take for peat moss to decompose? ›
Peat moss or “peat” is made of partially decayed plant material—usually mosses—that have been submerged without oxygen in wet, acidic conditions, like those found in a bog. The decaying process is very slow, taking up to 1,000 years to create a 36-inch layer of it!Do you water after peat moss? ›
Peat's porous micro-structure enables it to hold many times its own weight in water. It is dehydrated for sale but should be re-moistened before use. Ironically, when peat moss is dry it is hydrophobic – it repels water! Moisture beads up and rolls off, instead of quickly soaking in.How often should you water peat moss? ›
Watering frequency will depend on geographic location as well as the position in the house, type of plant, and the time of year. It is normal, for example, for watering to be around 4 weeks apart Summer. “First thing to know is that peat moss holds water.How much peat moss do you mix with soil? ›
Apply the peat moss as a 2 to 3 inches layer inside your garden. You can also apply it using a 2 to 1 ratio. Then, incorporate the moss into your soil's top 12 inches. You can add other amendments.Does peat moss keep soil loose? ›
Peat moss improves soil because it does not compact over time, so it loosens soil and aerates it. Adding peat moss to soil also helps increase the soil's capacity for drainage. In sandy soils, incorporating peat moss will help the soil to retain water and make moisture available for plants.What are the disadvantages of peat? ›
Peat soil is a non-renewable resource.
The most significant downside to peat soil is that it is an unsustainable, non-renewable resource. Harvesting peat soil can contribute to climate change by releasing greenhouse gas emissions like carbon dioxide and methane into the air.
What is the best way to spread peat moss? ›
Use a standard broadcast spreader to lay your grass seed across the entire lawn. Next, spread your peat moss over the seeded areas, creating a layer between 1/8"-inch and 1/4"-inch in depth. Finally, soak the area with water and keep it moist until the grass begins to sprout.What are the pros and cons of peat moss? ›
Unlike compost and soil, peat moss is completely sterile and harbors no disease organisms and rarely contains weeds or pests. This sterility makes it an optimum choice for starting seeds. Seedlings are particularly susceptible to fungal diseases that cause death. Fungi can't usually survive in peat.Which is better peat moss or manure? ›
Peat moss is mined from peat deposits and is usually considered a non-renewable resource. Animal manures are another source of organic matter and contain relatively larger amounts of essential plant nutrients than peat moss.Is peat moss good for hydrangeas? ›
You can amend with peat moss, as well, to keep the soil loose. Water again, fill the hole completely with the soil mixture, and water again. Hydrangeas love water (but not wet feet, they also like drainage) and need plenty to grow successfully.Is peat moss a fertilizer? ›
Peat moss holds onto nutrients; fertilizing or feeding the soil is a waste of time unless it can hold on to the nutrients. Fibers absorb them and then release them slowly to the roots of your plants.Should I put peat moss around my tomato plants? ›
Peat moss is an especially good mulch for tomato plants because it makes the soil more acidic as it breaks down. It's also an affordable option. Many gardeners like to use peat moss as a top dressing or mulch because it looks so attractive in the garden.What is a major problem with peat moss? ›
It breaks down too fast, compressing and squeezing air out of the soil, creating an unhealthy condition for plant roots. Peat moss can be a useful growing medium for containers, however, when lightened with a drainage material like perlite. The biggest problem with peat moss is that it's environmentally bankrupt.Does peat moss attract bugs? ›
Any organic mulch, whether it's derived from leaves, grass clippings, compost, wheat straw, or peat moss, has the most tendency to attract bugs and unwanted pests.Do cucumbers like peat moss? ›
The best results will come from healthy plant starts rather than seed, however. Make a soil mixture specific to cucumber needs with one part each of compost, potting soil, perlite and peat moss. Container grown cucumbers need plenty of water, but you must ensure they have good drainage as well.Do earthworms like peat moss? ›
Peat moss is a beneficial option for worm bedding because it absorbs excess moisture which could be harmful to the worms or cause them to escape the bin, seeking dryer pastures. It also breaks up heavy bedding, providing better oxygenation for the composting process.
Do peppers like peat moss? ›
According to the University of Washington Extension, peat moss keeps the mixture loose and compost gives plants all the nutrients they need to thrive. Peat moss retains moisture, keeping the peppers evenly moist and helping to prevent blossom-end rot, a condition that causes dark spots on the pepper.Does peat moss get moldy? ›
Mold on peat moss is usually created by the growth of filamentous fungi. If the water content is high, these organisms will grow on almost any type of organic matter. While the sight of mold growing on a freshly opened substrate bale may seem worrisome, they are not pathogenic to plants.Why is peat moss being banned? ›
Peat extraction also degrades the state of the wider peatland landscape, damaging habitats for some of our rarest wildlife such as the swallowtail butterfly, hen harriers and short-eared owls, and negatively impacting peat's ability to prevent flooding and filter water.What vegetables do not like peat moss? ›
What Vegetables Do Not Like Peat Moss? Plants that prefer more alkaline soil don't do well with peat moss. These include cauliflower, garlic, asparagus, spinach, many gourds, and others.What vegetables benefit from peat moss? ›
In the vegetable garden, peat moss can moderate extremes in soil dryness and wetness. This is particularly important when growing juicy-fruited plants with tender skins, such as tomatoes, strawberries and blueberries.
Before you add peat moss to soil, you should soak it in water for a few minutes first. Simply put some moss in a bin, fill it with water and let it sit. Remove the moist moss, give it a little squeeze to remove excess water, and then mix it into your soil at a 1:1 ratio.What is peat not good for? ›
Peatlands store a third of the world's soil carbon, and their harvesting and use releases carbon dioxide, the major greenhouse gas driving climate change. The biggest environmental risk from peatlands is if they catch fire, which happened spectacularly in 2015 in Indonesia on land cleared for plantations.Does peat moss keep bugs away? ›
Any organic mulch, whether it's derived from leaves, grass clippings, compost, wheat straw, or peat moss, has the most tendency to attract bugs and unwanted pests.Do tomatoes like peat? ›
To put it simply: tomatoes get their flavour from the soil in which they grow, just like wine. Flavoursome tomatoes need loamy soil that are rich in humus. Good quality peat-based potting compost is just the ticket.Should I mix peat moss in my vegetable garden? ›
Amending Soil with Peat Moss
Can you mix peat moss with soil? Absolutely. Just like compost, it's a great addition to garden soil, as well as most kinds of soil. Soil amendments with these materials provide water retention and aeration that can help house plants grow more easily.
Do flowers like peat moss? ›
Almost any potted plant you can buy grows in a soil mix that contains peat moss, and most bagged potting soil does as well. You can also buy it on its own to mix into your own potting soil blend. It's especially useful for growing flowers and food in containers, because it helps plants maintain the moisture they need.