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One of the most effective and controversial materials to garden with is peat moss. Effective because it works well in tons of situations, and controversial because of how it is sourced. Many gardeners buy it on the regular without even knowing what it is or what it’s doing in their practice.
Peat moss is sometimes maligned among eco-conscious gardeners. While they’re not wrong to question the origin of peat moss sold in stores, the truth is more complicated than one might think. Therefore, the topic deserves examination and discussion.
So we’ve dedicated this piece to this interesting moss, what it is, and how to use it in the garden. We’ll also touch on why it has been looked down upon by gardeners who appreciate an ecologically sound practice. All this will help you as a gardener make the best possible decision about using it or an alternative.
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What Is Peat Moss?
A peat definition is in order! How did this material gardeners spring for at the local nursery go from its natural source to a plastic bag? Peat moss comes from sphagnum moss, harvested from peat bogs in the Northern Hemisphere. The moss is then decayed and dried in the peatland, meaning it is allowed to lie exposed to the sun. What results is a dark brown fibrous material that is excellent for gardening.
This moss is an excellent amendment, particularly in sandy soils or in potted plants that have difficulty retaining moisture. We’ll talk more about how to use peat moss later. First up, a few distinctions!
Peat v Sphagnum Peat Moss
The term peat moss most often refers to the lower levels of peat found in a peat bog. Sphagnum peat moss is the plant from which the peat moss we use for gardens is derived, but most of the peat we like to use is the long-decayed form that collects deeper in the bog layers. Over time, it becomes packed down, compressed, and decays into a lovely spongy mass. The lower levels may also contain other decomposed organic material, like other rotted plants.
The top portion of the sphagnum peat moss has its uses, too. While it’s stringier than the deeper decayed moss, it is often used in reptile cages or terrarium use. It is not as decayed, and still resembles the plant it used to be.
Most of the US’s sphagnum moss resources come from Canada or the northern parts of the United States. Sphagnum moss grows specifically in wetlands in tundra areas. There are sphagnum peat bogs in South America as well, but our commercial peat moss comes from the north.
Both have similar applications, but in general, the decayed form of peat moss is much more acidic than the one that still looks plant-like. Typically, the only peat you’ll find at the garden center is the lower, more decomposed material. It takes genuine work to find the dried sphagnum moss; typically, it’s only through pet stores or specialty reptile shops that you’ll find good quantities of it.
How Does Peat Moss Form?
We’ve talked generally about how peat moss is created. Now let’s take a closer look. Sphagnum moss grows freely in peat bogs or wetland areas of cool-climate tundras and conifer forests. A look at the video posted in this article will give you an idea of just how lush this plant is.
Certain areas of these peat bogs are designated specifically for harvesting, most of which is done via a vacuum harvester. It’s not the live moss that’s desired, but the decayed moss that sits below.
Most harvesting occurs between May and September. Before this occurs, all the upland plants must be removed. Black spruce and tamarack trees are removed along with carnivorous plants, shrubs, and herbaceous plants.
Then the top layer of the vast sphagnum patch is removed and relocated to other areas of the bog which have not been disturbed, where it can thrive. The decayed, dried sphagnum moss is allowed to lay in the sun for 2 to 3 days where it dries. It’s then scraped up with the harvester and sucked into a receptacle. Then it’s moved to a factory for processing and packaging.
Some are bagged separately, and some are combined with decayed organic materials to be incorporated into potting soils sold worldwide. Some are made into peat pellets, and some are sold as simply peat moss. Then it hits the shelves, where you’ve likely seen and bought it.
Benefits of Peat Moss
Because peat moss is so widely used in gardening, you may wonder what all the hubbub is about. Here are the main reasons people use peat moss in their gardening practice.
Moisture Retention
Because of the cellular structure of sphagnum moss, peat moss is an excellent resource for water retentive properties. Sphagnum moss has two kinds of cells: those that assist in photosynthesis and those barrel-shaped cells that retain water. Both of these are necessary for thriving peatland, as much of the main source of nutrition for sphagnum is in the water and decayed moss below.
The moss will release the water to maintain the wetland as well. This is why peat moss is such an essential addition to gardeners’ soil. Much of what we do is figure out the best possible ways to carry out good water retention in the garden. Peat moss bogs and in turn peaty soil are the main sources of moisture retention for many. That’s why it’s commonly used in potting soil, and to line wire baskets.
All-Natural Source
Another thing organic gardeners appreciate is all-natural sources. Not only is peat moss organic, but it’s also only one step removed from the plants in the peatlands it comes from. Bog moss is essentially organic matter used in soil mixes, and bulk peat moss is sold on its own too. Peat moss doesn’t have any chemicals in it either. It’s free of fungus, bacteria, harmful chemicals, and weed seeds.
Sterility
Peat moss is not only organic, and has excellent water holding capacity, but it is also completely sterile. As we mentioned in the last section, there are no chemicals used in processing peat moss. Because there are no fungi, bacteria, and weed seeds, this media is clean as a whistle. Peat moss also has antiseptic qualities that originate in polysaccharides which suck harmful bacteria into cell walls. There’s a long and very interesting history of the use of this moss in medicine and as bandages.
Widely Available
Pretty much every store you go to will have some form of peat moss available, whether it be a potting mix, peat moss, or specifically sphagnum peat moss, you’ll have no trouble locating a source. So many growers rely on this plant for soilless mixes, starting seeds, and soil amendment and peat moss has been on the market for a long time. Therefore, it’s reliable.
Doesn’t Compact
Although compost is nutrient-rich, it doesn’t compare to peat moss when it comes to anti-compaction capabilities. Much of this is related to the moisture-retentive properties of peat, which keeps the soil it’s in aerated and light. It’s an excellent amendment for topsoil, which can compact quickly and easily. I know peat in soil would have been a welcome addition to my first raised bed, which I readily filled with the cheapest topsoil I could find, only to plant my crops in what was essentially cement.
Drawbacks of Peat Moss
Now, what are the disadvantages of peat? You may have heard about some of these. You may also find the truth about peat is more complex than you once thought.
Non-Renewable
Let’s start with the environmental concerns. On the whole, peat is a non-renewable resource. The fact that it outperforms other materials in the garden is why it was overharvested for a long time with little thought about how using moss for plants was contributing to ecological decline.
Another one of the environmental concerns is that removing plants in bogs to access sphagnum moss contributes to global warming. The vast majority of plants in peat bogs sequester carbon dioxide. When all the plants are removed, the decomposition process peat goes through releases carbon dioxide into the atmosphere. Top that off with the fossil fuels used to power the harvesters, and you may be able to see where the concerns lie.
One of the best things to happen in the peat world in recent years is efforts toward making peat a renewable resource. Through organizations like the International Peat Society, ethical and ecologically sensitive harvesting has been put into practice. Living plant material is relocated to make extraction more ecological. They have developed initiatives to mitigate the conflicting interests of land protectors, conservationists, and peat producers.
No Nutrients
Peat doesn’t have any nutrient content, unlike compost, animal manures, and other soil mixes. Therefore, it’s only good for consistency and water retention. Peat moss soil is never just peat moss. Mixing peat moss with soil is what creates these blends. If you’re growing plants in peat, you’ll always need some source of nutrients in addition to the moss.
Hydrophobia
While peat is very moisture retentive, the fibrous material is also hydrophobic when it dries out. Therefore, it takes a significant amount of water to re-activate the retention it provides when slightly moist. Peat soil that has dried out may require some kind of surfactant, or wetting agent to break the tension and allow it to absorb water again.
Acidity
The base-level peat moss pH is 5.5 (sometimes even more acidic at 4.0) at least at the start of its use. While this may not seem like a problem for people who love to grow acid-loving plants, the low pH of acidic soil may be an issue for plants that need alkaline or neutral soil. Using peat may initially make your soil pH low, but studies have shown it will neutralize within a day or so.
Therefore, if you’re using peat to plant live crops, know it will take some time for the acidic soil to balance out and neutralize in your garden.
Peat Moss Alternatives
What can I use instead of peat moss? There are several choices! One of the most commonly used alternatives is coconut coir, a material made of coconut fiber that is extracted from broken-down coconut shells. Coconut coir can have a high salinity content, though, making it necessary to water more. Other materials like worm castings serve a similar function, adding water retentive properties to the soil which helps gardeners grow plants.
Compost is a great alternative as well. Not only is compost water-retentive, but it’s also full of macro and micro nutrients needed to keep every plant healthy. Rice hulls are the byproduct of hulled rice that you buy in the store. They provide aeration and lightening. Pine bark also provides some nutrition and helps retain moisture. Finally, pine needles add acid content to the soil as they break down, making them great for acid-lovers.
How To Use Peat Moss
So, what is peat moss good for? And what is peat moss used for? Let’s talk about it! While alternatives exist, it’s hard to outperform the old standby.
Peat Moss for Seed-Starting and Soil-Less Mixes
When it comes to the uses of peat moss, seed-starting is one of the places where it shines. Mix peat with perlite and vermiculite and you have a great seed starting mix that is also soil-less. This mixture provides seeds with the right amount of drainage and aeration that will help plant roots grow strong and healthy. Add a little compost to feed plant roots some nutrients too!
Another one of the best peat moss uses is in soilless potting mixes. These are great for plants that don’t need a lot of nutrition to grow but do require air circulation and drainage. Most soils (even peat soils) host bugs, fungus, or bacteria. That’s why a soil-less mix is one of the best uses for peat moss.
Peat Moss For Lawns
When should I use peat moss on my lawn? Peat moss uses can include lawn as well as garden. The timing is key, though. It’s best to use this material when you are planting sod, rather than using it while your lawn is growing. That’s because of the acidity spike it can create in the existing soil.
This acidity can make lawn work harder because it kills off beneficial microbes and earthworms. So apply a layer of moss to the ground before planting your sod, and you’ll have an extra layer of water to help it root in.
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.
Adding it to sandy soil lightens it, just as coco coir would. So if you see peat moss on sale when you are looking for a soil amendment, consider peats.
Frequently Asked Questions
Q: Is peat moss good for all plants?
A: It provides an initial spike of acidity to some that may make coco coir preferable. It’s a great soil amendment, though!
Q: What is the difference between peat moss and compost?
A: It doesn’t have any nutrition, and doesn’t compact as much as compost does. If you need a soil amendment that has macronutrients and micronutrients, go for compost. For aeration and lightening, go for peats.
Q: Why is peat moss being banned?
A: While it is banned for home gardener use in the UK starting in 2024, it’s still available on its own or as a soil amendment in the US.
Q: What plants grow well in peat?
A: With enough additions, most plants will do just fine. Soil heavy with these materials grows acidic lovers best. Think blueberries, hydrangeas, and nasturtiums.
Q: Is peat moss toxic to humans?
A: Untreated moss may contain fungi that can cause illness. Most of those you find in stores are well-treated. This is not a concern for most gardeners.
Q: Do tomatoes like peat moss?
A: It’s great as a soil amendment for tomatoes because it helps retain consistent moisture levels needed for plump, delicious fruit.
Q: Can you use too much peat moss?
A: Definitely. You want to balance your usage with other materials. Not only will this help you grow healthier plants, but it will also help limit the overconsumption of the material overall.
FAQs
Is sphagnum peat moss good for gardens? ›
It makes an excellent soil amendment to potting mix and garden soil, and mounds of peat moss can even serve as hydroponic growing media.
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.
Can I use sphagnum peat moss for all plants? ›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.
Can you just put peat moss on top of soil? ›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.
How often should I water plants in sphagnum moss? ›How often to water your Sphagnum Moss. Sphagnum Moss needs 0.8 cups of water every 9 days when it doesn't get direct sunlight and is potted in a 5.0" pot.
Why should gardeners not use peat? ›Plantlife, along with the RSPB, Wildlife Trusts and Friends of the Earth, is calling on government and industry to replace peat use in gardening and horticulture. Damaging peatlands has a knock-on effect on wildlife, carbon stores, flood risk and water quality.
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.
Is peat moss being banned in the United States? ›The Government has announced it will be banning peat compost sales for amateur gardeners from 2024.
Which one is the disadvantage of using sphagnum peat moss? ›✗ Too acidic for some plants
Peat moss can make the soil too acidic for plants that need an alkaline or neutral soil pH. Before using peat moss in your garden, find out if your plants can tolerate acidic soil. Otherwise, you might end up killing them.
Sphagnum moss is especially ideal for lithophytic or epiphytic plants (like orchids and some aroids) which need moisture at the root zone, but also lots of airflow.
Can I use sphagnum peat moss instead of peat moss? ›
Sphagnum moss and sphagnum peat moss are terms used to refer to two different forms of the same plant. Both are interchangeably referred to as peat moss.
Why do gardeners add sphagnum moss to soil? ›You can add it into your soil to achieve any of the following results: Help drier, sandier soils retain moisture for longer. Help heavy clay soils loosen up and have better drainage. Increase the amount of organic material in the soil, which breaks down over time to provide nutrients.
Should you fertilize plants in sphagnum moss? ›Sphagnum moss doesn't carry any nutrients itself. However, that's when liquid fertilizers come in and you will have to use them anyway. The main role of sphagnum moss is providing air and moisture for your plants. It absorbs nutrients from fertilizers so the roots can take in later.
Should I mix sphagnum moss with soil? ›Depending on the plant, it might be used on its own or mixed with soil or another potting medium. On its own, waterings may need to be more frequent and fertilizers may be required as sphagnum moss does not hold much in the way of nutrients.
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.
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.
Can you overwater sphagnum moss? ›The general answer is a resounding yes. Think about your watering habits. While we want to keep our plants thriving, overwatering is a common issue regardless of the potting mix you choose.
How do you prevent root rot in sphagnum moss? ›- Avoid mixing particles sizes. The smaller pieces fill the gaps between the larger ones, reducing the sizes of the void space.
- Do not pack the potting medium too tightly. That is particularly important with sphagnum moss.
- Repot into fresh medium on a regular, timely basis.
While the experiments performed in this study proved that water can indeed be purified using Sphagnum moss, several factors need to be taken into consideration and certain problems faced during the course of the study need to be brought to light so that future endeavours related to this study can develop means of ...
Why is peat no longer used in compost? ›Why is peat compost bad for the environment and why is it being banned? For peat to be healthy and function efficiently, it must remain wet. Its extraction for human use dries the peat causing the area to degrade and also increases the risk of wildfires.
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!
Is peat better than compost? ›Peat moss releases nutrients in your soil in time as the plants require. This saves valuable nutrients which are otherwise lost through leaching. Peat Moss speeds the composting process, reduces odours and controls air and water in the compost pile.
Why not to use sphagnum moss? ›The first is that the soil stays too moist for the plant because the sphagnum moss retains the moisture for long periods. The second problem is that the moss could dry out the soil around the root system, because it has absorbed the water from that section of soil.
What plants 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.
What grows well in peat soil? ›Heather – likes damp, peaty soils which makes it ideal for acid ground. Camellias – woodland plants originally from Japan, China and Korea, Camellias like moist peaty acid soil best, but do grow in other soils provided there's plenty of organic matter, and adequate drainage.
Is there a peat moss shortage 2022? ›In 2020 and 2021, the beginning of the supply chain issues and product shortages began and the extreme shortages of peat moss have continued into 2022.
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.
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.
Does sphagnum moss make soil more acidic? ›Sphagnum peat moss is often suggested as a soil amendment to decrease soil pH. However, most peat moss found in garden centers is neutral or slightly acidic. Only Canadian sphagnum peat moss has a low pH of 3.0 to 4.5 and will effectively reduce soil pH.
Does sphagnum moss make soil acidic? ›Sphagnum moss is pH neutral.
Yes, you read that right. Generally, the pH of sphagnum moss is pH neutral. It is soft, pliable, and very water-retentive. It is used to line baskets, as a seed-starter medium, as a medium that most big-box store Phalaenopsis orchids are growing in, and as an amendment in potting soils.
How long does it take for sphagnum moss to break down? ›
This high quality moss will last for 2 to 5 years in the pot depending on the quality of your irrigation water as well as how much you water and fertilize.
Does sphagnum moss mold? ›Sphagnum peat moss is no different from any other organic matter, such as bark, compost, coir, mulch, etc. The molds which grow on peat moss and growing media are saprophytic, meaning that they feed on dead plant material and are not pathogenic or harmful to plants or people.
How long does it take for sphagnum moss to grow? ›Sphagnum moss has a very slow growth rate and can take about nine months or more to grow and reach maturity. This moss grows up to 0.75-4.75 inches yearly. A very interesting feature of Sphagnum moss is that it can hold water like a sponge and can store and hold water about eight times its weight.
What plants like sphagnum peat moss? ›Sphagnum moss is especially ideal for lithophytic or epiphytic plants (like orchids and some aroids) which need moisture at the root zone, but also lots of airflow.
How do you add sphagnum peat moss to soil? ›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.
How long do plants stay in sphagnum moss? ›A high quality sphagnum moss will last you for good 2 or three years. You probably will need to repot the plant way before the moss goes bad. Confusion no 3: You cannot use sphagnum moss for long term because it doesn't have any nutrients.
What types of plants grow best in peat soil? ›Drained fen or light peat soils are among the most fertile arable soils. Crops such as potatoes, sugar beet, celery, onions, carrots, lettuce and market garden crops are commonly grown. Cereals produce low yields. On light undrained peats, or where the water table remains high, the main crop is grass.
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.
Sphagnum moss has several fantastic properties that will help you grow lush, healthy plants. It is moisture-retentive, has a fibrous texture that facilitates drainage, and is less prone to soil-borne diseases compared to most potting mixes. Plus, it has a unique decorative appeal.
Do I need to rinse sphagnum moss? ›Before planting your sundew or other carnivorous plant in sphagnum peat moss or a peat: sand mixture, I always recommend that you rinse the peat before using it.
Do you add water to sphagnum moss? ›
This is also a great time to use a spray bottle to spray down the top of the moss. This is usually enough moisture—remember, the baggie on top of the cutting will help retain moisture, so you don't need to add much water!
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.