- Peat vs Peat Free – Choose the right Potting Compost
- What is Peat Free Compost? The Meaning of Peat Free Explained
- Why is there Peat in Most Composts Commonly on Sale?
- Why go Peat Free?
- Peat Free Compost Made from Household Green Waste
- Other Sources and Brands of Peat Free Compost
- Peat-free compost – what are the environmental benefits?
- List of Peat Free Compost Products
- Summary – What is peat free compost?
- Commercial Mixes
- Make Your Own
- Myth Series: Peat-Based Growing Media are Sterile
- Biological Agriculture & Horticulture
- Is this popular gardening material bad for the planet?
Peat vs Peat Free – Choose the right Potting Compost
Potting composts are designed to be the best growing medium for plants. Traditionally, peat has been used as a component because of its ability to retain water and nutrients.
Nowadays, with more awareness around peat-bog depletion, and peat as a limited resource, many gardeners prefer to use peat-free composts.
Peat-free composts are great for water retention but, for plants that require good drainage, adding a bit of grit and sharp sand to the mix will help support growth.
Most peat-free composts are carefully blended to provide optimum growing conditions and the quality and reliability continues to improve. Where necessary, a liquid feed can be used in conjunction with a peat-free compost to boost nutrient levels.
If a potting compost is not labelled peat-free, it most likely contains some peat. Peat-free composts tend to be more expensive because they require more processing.
When choosing a peat-free potting compost, be sure to follow manufacturer’s instructions and be prepared to alter your watering and feeding patterns if you previously used peat-based products.
If you are concerned about peat use in your garden, you can also support reduction by buying only potted plants which have been grown in peat-free compost.
“Peatlands contain one of the world’s most important carbon stores – when they’re drained the carbon is released back into the atmosphere where it contributes to global warming.”
“Peatlands are important water stores, holding about 10 per cent of global freshwater; peat takes so long to form – it grows by about 1mm per year – that it cannot be regarded as a sustainable material. Commercial extractors typically remove up to 22cm of peat per year.”
“38 per cent of the peat used in the UK comes from within the UK, 56 per cent from the Republic of Ireland, 6 per cent from Northern Europe.”
“In 2008, the Growing Media Initiative scheme was launched, managed by the Horticultural Trades Association in conjunction with the Growing Media Association, DIY and Garden Centre retailers, Defra, the Royal Society for the Protection of Birds and the Royal Horticultural Society. It aims to increase awareness of the plight of the world’s peatlands and the need to use more sustainable materials in gardens, and in so doing, develop a practical way forward to achieve peat-replacement in the UK.”
“Amateur gardeners use 66 per cent of the total peat consumed in the UK, most of it in growing media such as multi-purpose compost and growing bags.”
We understand that you would like to know what Peat Free Compost is? Peat free compost is explained here so read-on!
What is Peat Free Compost? The Meaning of Peat Free Explained
Peat free compost is available for home garden use and to businesses. Just as it says pet free compost contains no peat. It is compost which is made from other types of composted biomass.
Examples of materials used in peat free composts are:
- Composted garden waste and bark
- Coir-based (i.e. fibre from the outer husk of the coconut) mixes containing biochar
- Composted bracken and wool waste
In the United Kingdom and many northern United Kingdom and many northern United Kingdom and many northern countries in the past, it has been common practice to use peat in compost sold commercially..
Image; Peat that has recently been cut from lowland peat bogs, and is ready to be used as a compost.
The most famous products of the past Leventon’s compost were all 100% peat with added chemical fertiliser. That’s it – peat with added chemical fertiliser to provide nutrients for the young plants.
Lowland peat bogs and their wildlife are are now threatened from this, commercial use of a rare natural resource.
Peat extraction for garden composts and other uses in peat garden composts and other uses peat garden composts. unfortunately, the extracted peatland takes a very long time to recover and re-grow.
Peat moss grows very slowly. Even if these bogs were flooded again it would take hundreds of years before the peat was able to regrow and be harvested.
Once the peat has been used it is usually gone forever, because the land becomes drained for agricultural use.
Peat land wildlife has gone forever after most peat cutting.
Peat land wildlife such as dragonflies, butterflies, and birds, depend on peat for their survival.
There is no peat for their survival there is no need. You can now choose alternatives to using peat based composts.
Much like managing wetland restoration, peat bogs can be remediated, but are never the same as an untouched ecosystem. Like old growth forest, peat may be harvested rapidly, but takes generations to replace, as it only grows a few millimeters (or less) per year. Each year almost 32 million cubic yards of peat are harvested for horticultural use. via organicmechanicsoil.com
Peat free compost is often made from green waste, garden, and yard waste.
It is a totally natural material and eco-friendly product with a wide range of eco-friendly product with a wide range of eco-friendly uses.
It can contain ingredients such as uses such as recycled garden materials bark-fines Koya and wood fibre high quality par 100 Koya and wood fibre high quality PAS 100 compost.
Why is there Peat in Most Composts Commonly on Sale?
Peat is a wonderful medium for holding water. It also improves soil quality when mixed with soil by raising humic content and holding the structure open for healthy root growth. When first placed in the ground it also holds fertilizer added when it was packaged. The fertilizer is used by the plants, and creates healthy growth.
When plants grow in swampy areas die, they do not decompose properly. Instead they turn into a partially rotted organic material; a material know as peat. Many multi purpose composts contain peat as it can help retain water. It is for this reason that some gardeners will also bulk-buy peat in order to add to raised beds so they stay moist.
It is noteworthy that if your shop bought compost does not say that it is peat free then there is a strong chance that it does indeed contain peat.
Why go Peat Free?
There are many reasons for not using peat; firstly, peat renews at approximately 1mm per year, therefore it is considered a non-renewable resource. Secondly, peat bogs store carbon, a lot of carbon. In fact the equivalent of 20 years of industrial carbon is stored in British peat bogs alone. The more that this erodes, the more carbon is released into the atmosphere.
What’s more, when peat is cut the exposed areas that remain often dry out, thus releasing carbon even when the peat is not cut and used as compost.
Thirdly, peat bogs are a threatened habitat. A unique ecology, which is home to a huge array of flora and fauna. Many of these species are found nowhere else, but thrive in such conditions. This includes birds, such as snipe and the skylark, which breed on peat bogs. Many lovely butterflies and dragonflies would also be lost if peat bogs disappear.
Although some of the cut peat is used as fuel, the vast majority of it is used by gardeners. It seems that in our attempt to create our own little wilderness, peat compost users are selfishly robbing another. via theecologist.org
Peat Free Compost Made from Household Green Waste
The green waste used in these products is guaranteed to only be these products. Plus, green waste is guaranteed to be made made only from green waste, and not from the organic fraction of mixed household organic waste, fraction of mixed household waste it has been estimated that around:
- Half a million tonnes of carbon dioxide is emitted each year as a result of peat extraction from united kingdom peat-land.
- In addition this for horticultural use in addition this for horticultural use in addition this doesn’t take account of the fact that we (the UK) imports as much peat again each year from overseas, but, using peat free compost is even better than just saving all this direct carbon dioxide being emitted.
- The reason that peat free compost is so that peat free compost is so beneficial to the environment, is that if the green waste it is made from was not made into compost, it would be sent to landfill.
- Not only are landfills much disliked and damaging to the local environment but this organic waste also creates methane. If methane escapes to the atmosphere it is 21 times more damaging as a greenhouse (climate changing) gas than carbon dioxide.
Other Sources and Brands of Peat Free Compost
Peat free compost can be wonderful compost. Some of my best tomatoes have been grown in pots where toadstools (not to mention the odd toad) have appeared. This is no surprise: fungi decompose organic matter, releasing plant foods as they do so. Many peat-frees are blessed with beneficial, plant-friendly fungi which are largely absent from sterile, peat-based mixes.
Locating a good, reliable supplier of quality peat-free compost can be frustrating, and peat-based products still tend to elbow them out. Fortunately, Carbon Gold, Fertile Fibre and Dalefoot Composts (suppliers of Wool Compost) all offer a reliable mail order service. Clubbing together with friends to place a larger order can save money.
For those who want to be as organic as possible, from seed to plate, Carbon Gold and Fertile Fibre both offer coir-based peat-frees, certified by the Soil Association for organic growing (both also make compost used by commercial organic growers).
To grow acid-loving plants, such as azaleas, blueberries and camellias in containers, peat and lime-free potting composts are available. Vital Earth Ericaceous Compost is available from garden retailers, and Ericaceous Wool Compost (from Dalefoot Composts) by mail order. via telegraph.co.uk
Peat-free compost – what are the environmental benefits?
Peat is mined from raised bogs, the remains of a priceless primeval wilderness. They are formed from the decaying remains of plants such as sphagnum mosses. These bogs are home to a variety of plant and wildlife species which can only exist in this unique environment. Because of this, many peat bogs are Sites of Special Scientific Interest (SSSIs).
The attractively bagged peat packs that you see in a garden centre represent an ecological disaster.
The UK Government’s policy is that peat should be conserved. Conservationists and campaigning organisations are working to achieve a complete ban on peat mining.
You can learn more about the issues by reading English Nature – peat bog conservation PDF. Or search for ‘peatlands campaign’ in Google.
Gardening enthusiasts account for 60% of the peat bought in the UK. So, by purchasing an alternative product, you are making a real difference. via fertilefibre.com
List of Peat Free Compost Products
|Peat Free Compost Product||Compost Source|| Price
|New Horizon organic and peat-free multipurpose compost||~||£5.99 for 50 litres|
|Vital Earth multipurpose compost||Composted garden waste and bark||£5.99 for 50 litres|
|Carbon Gold all-purpose biochar compost||Coir-based mix containing biochar||£8.95 for a 20-litre bag|
|Wool compost||Composted bracken and wool waste||£12.95 for 30 litres|
|Fertile Fibre multipurpose compost||Organically certified, coir mix||£11.95 for a 35-litre bag|
Summary – What is peat free compost?
We hope that you will now understand why peat free compost is the type of compost all good gardeners should seek out.
When you look for compost, you should seek out peat free compost.
We hope you enjoy your gardening and have success with Peat Free Gardening. Article includes text as found on Youtube at: CompostTheVideoExplanation.
0 SharesAs with any garden, soil preparation is what really counts when it comes to being successful growing in containers. It’s the foundation. It’s the staff of life. Pick your life-giving metaphor and you get the idea.
In other words, select the right potting mix recipe for your plants and they will thrive. Skimp on the soil and you’ll get weak, non-productive plants that require more work to maintain and are susceptible to all kinds of pest problems.
What is the perfect mix? That depends. Every professional gardener has his own “secret” recipe just like every Italian grandmother has her own way of making tomato sauce. However, most experts agree that a good container medium should be lightweight and drain well, yet contain enough organic matter to hold moisture and nutrients even through hot, dry weather.
Get your potted crops off to a great start and keep them healthy with premium quality potting soils. Designed to provide root support, moisture retention and healthy nutrients, these organic mixes will give you maximum results.
Note: Ordinary garden soil is not recommended as a potting mix. It’s usually too heavy and may contain weed seeds, diseases, and insect pests.
Most commercial potting mixes are the seller’s best attempt to provide for aeration, water retention and nutrients. Of course, not all commercial soils are the same. The old adage “you get what you pay for” can really come into play here. Avoid inexpensive soils that just say “topsoil” or “compost” on the label. That mysterious topsoil may be anything and could very well be old, tired soil that comes from land that’s been farmed to death. Poor topsoil can be completely depleted of nutrients, but rich in nasty chemical pesticides and herbicides, another leftover from life down on the farm. Something merely labeled “compost” could very well be made from toxic sludge (often called biosolids) or just ground up wood chips and nothing else. Play it safe and buy quality organic potting soil.
So what should you look for? “Certified Organic,” that’s what. Beyond that, look for specific ingredients. Don’t buy mystery soil. Remember the old sci/fi classic, Soylent Green? It pays to know the contents of your food or the food of your plants.
Tip: Store leftover soil in a tightly sealed bag to keep out soil-dwelling pests, like fungus gnats. Read our article Contaminated Potting Soil and Compost to learn more.
Make Your Own
Of course, you don’t have to purchase potting soil. You can make your own. Sure, it’s more work, but it can be more gratifying, plus you’ll know the exact contents of the soil since you’re the one who has mixed it up. A good potting mix recipe contains sterile garden loam, sand, peat moss (or coconut coir) and other additives as needed.
#1 SOILLESS MIX
Not just any grow medium… FoxFarm® Light Warrior is packed with beneficial microbes (mycorrhizae) to stimulate root growth, humic acid to promote seed germination and earthworm castings to help plants thrive. It’s the perfect fast-draining, lightweight mix for your indoor/ outdoor gardens. Available in a 1.0 cu ft bag.
Classic Soil-Based Mix:
- 1 part peat moss or mature compost
- 1 part garden loam or topsoil
- 1 part clean builder’s sand or perlite
The organic material in the above mix provides structure and the sand will improve drainage. A balanced, slow-release organic fertilizer may also be added to the mix.
Cornell Soilless Mix (adapted for organic growers*):
- 1/2 cubic yard peat moss or coconut coir
- 1/2 cubic yard perlite
- 10 lbs. bone meal
- 5 lbs. ground limestone
- 5 lbs. blood meal
* This soilless mix was developed at Cornell University for commercial growers, but is easily adapted for home use. I have substituted select organic fertilizers in place of synthetic fertilizers.
The Perfect Raised Bed Soil Mix
Good organic garden soil is the single most important ingredient for healthy, nutritious vegetables. It is loose and fluffy — filled with air that plant roots need — and has plenty of nutrients and minerals essential for vigorous plant growth and bountiful yields. Filling your raised beds is an opportunity to get high-quality soil and to fine-tune the mix of fertilizers and amendments.
The following soil mix was developed by Planet Natural to fill a 4’ X 8’ raised bed one foot deep (32 cu ft).
5 bags Black Gold Peat Moss, 2.2 cf x 5 = 11 cf
3 bags Teufel’s Organic Compost, 3 cf x 3 = 9 cf
4 bags Worm Castings, 1 cf x 4 = 4 cf
3 bags Organic Chicken Manure, 1 cf x 3 = 3 cf
2 bag Therm-O-Rock Organic Vermiculite, 2 cf x 2 = 4 cf
3-6 lbs Azomite
1-2 lbs Kelp Meal
3-6 lbs Oyster Shell Flour
2-4 lbs All-Purpose Fertilizer
Have on hand all the ingredients for your soil mix before you start filling the beds, and pre-mix as much as possible, on a large tarp if necessary, to avoid pockets of peat, manure or any other ingredients.
Note: Do NOT use pressure treated wood or railroad ties for your raised bed frame because of chemical leaching.
Myth Series: Peat-Based Growing Media are Sterile
Tuesday, September 12, 2017 | Susan Parent
There is an assumption that peat moss and peat-based growing media are sterile. People are surprised to find out that this is not true. In fact, if peat moss was sterilized, then it would have no living organisms in it, like bacteria and fungi. But the presence of natural, beneficial microorganisms in Sphagnum peat moss is essential for a healthy crop. So why does the myth that peat-based growing medium are sterilized / sterile persist?
Origin of Sphagnum Peat Moss. Sphagnum peat moss represents roughly 70 to 80% of the total volume of most peat-based commercial growing media. Sphagnum peat moss comes from wetland ecosystems, called bogs, where sphagnum mosses are the dominant plant species (Figure 1). Sphagnum peat bogs are widespread throughout Canada, Baltics, Russia, Scandinavia, etc. and formed thousands of years ago after glaciers that covered these regions receded. Each year sphagnum moss grows and floats on the surface of the bog and then dies back, forming a layer of dead material that accumulates at the bottom of the bog. Over the millennia, the sphagnum peat layer became thick and compressed. The top layer has young, live moss while the bottom layer has gone through a humification process which decomposes the sphagnum peat moss into a dark, humus-like material (Figure 2).
“Figure 1: The sphagnum peat moss plant. Source: Premier Tech Horticulture.”
“Figure 2: Cross section of a typical sphagnum peat bog. The upper layers of the bog
have the most fibrous, least decomposed peat, while the peat at the bottom of the bog
is a decomposed, black peat humus. Source: Premier Tech Horticulture.”
Not Sterilized, but Essentially Sterile: Sphagnum moss, although not sterilized, is considered “essentially sterile” for several reasons:
- Sphagnum Peat Bog Environment: All water that enters a Sphagnum peat bog comes from precipitation which has no mineral nutrients. Due to the low mineral nutrient content, it is easy for sphagnum moss to create a very acidic environment, with a pH around 4.0, which is close to the acidity of certain vinegars. Mineral nutrients are also needed to support the growth of microorganisms and most plants. This combined with the fact that sphagnum peat bogs are located in wet, cold climates, does not support the weeds or pathogens that cause problems with greenhouse crops.
- Sphagnum Peat Bog Plants: Sphagnum peat bogs are not, nor have been, used as agricultural land, which means there is no monoculture in this natural environment, which can lead to propagation of pests and diseases normally associated with cultivated crops. Another vector of diseases and insects are weeds. Most of the weeds that are typically found in the greenhouse or agricultural environment do not occur in sphagnum peat bogs, so their seed is not found in sphagnum peat moss.
- Peat Storage and Manufacturing: Before sphagnum peat moss is packaged, it is harvested with vacuum harvesters and then piled on the edge of the sphagnum peat bog where horticultural pests or weeds cannot access it. When needed, it is taken directly to the factory where it is screened and either baled or used for the manufacturing of growing media. Once the peat is baled and sealed in a plastic bag, pests cannot penetrate the package, unless it is punctured or damaged during storage.
Presence of Beneficial Fungi and Bacteria: In addition to the fact that there are few pathogens or weed seed that could enter into a sphagnum peat bog, there are beneficial microorganisms present that compete with pathogenic organisms, keeping their populations in check. Sterilizing sphagnum peat moss would kill these beneficial microorganisms. Some of these beneficial microorganisms are anaerobic, which means they thrive in the absence of oxygen, and may produce odiferous by-products if their populations build up. If so, these odor causing by-products do not harm plants or people and will dissipate after opening the bale and exposing it to oxygen.
For more information, see our accompanying article entitled “Odors in Growing Medium” and also the following article on our website: “Presence of mold on growing media”.
In conclusion, to say that growing media and peat moss are sterile or sterilized is incorrect. From an industry standpoint, there is no need to sterilize sphagnum peat moss as it is essentially free of pathogens and weeds and sterilization would kill beneficial microorganisms that compete with root disease pathogens.
For more information on this topic or any of our PRO-MIX and peat-based products, please contact your Premier Tech Horticulture’s Grower Services Representative.
Biological Agriculture & Horticulture
Peat is the main component of growing media in horticulture. Increasing demand, environmental concerns and rising costs for peat make the search for alternative materials imperative. Much research has been performed aiming to find high quality and low cost substrates from different organic wastes such as compost and thus decrease peat consumption. Biochar is a carbon-rich material that has attracted important research as a soil amendment. However, its potential utilization as a peat substitute for growing media formulation remains less well explored. The aim of this study was to evaluate the effects of sewage sludge and sewage sludge biochar on peat properties as growing media and on lettuce (Lactuca sativa) growth. Sewage sludge transformation into biochar proved to be a sustainable waste management approach in order to promote their future use as growing media components. Addition of biochar from sewage sludge increased the N, P and K content of growing media. The biochar addition to peat at a 10%vol rate increased lettuce biomass production by 184–270% and the shoot length by 137–147% despite hydrophysical properties not being improved. Also, biochar addition had a positive effect on growing media microbial biomass which increased more than 966%. In spite of the higher metal concentration in biochar than in sewage sludge, their transfer to plants seems to be reduced when compared with direct sewage sludge use.
Is this popular gardening material bad for the planet?
Each year, professional plant growers and hobby gardeners alike go through vast quantities of commercial soil products for seed starting, container gardening, patching lawns and improving growing beds.
In 2006, Mark Highland launched a business to make, blend and sell all those concoctions, but with one key difference. His mixes would not contain the ubiquitous ingredient in most bagged growing media: peat moss.
Virtually all of the peat moss sold in the United States comes from the vast sphagnum moss bogs of Canada. Often mixed with a mineral named perlite, it is highly valued by horticulturists for its ability to retain moisture and oxygen without becoming waterlogged or heavy. It is generally sterile and naturally suppresses a fungal disease that can afflict seedlings, making it a natural choice for seed starting.
So why would Highland, owner of Organic Mechanics in Modena, Pa., go to considerable trouble to avoid it?
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. Peatland fires account for up to 5 percent of human-caused carbon emissions, according to the United Nations, which last year launched a peatlands conservation initiative.
Concerns for peat bogs have led to the creation of alternatives using compost, pine bark and coconut fiber. From left: peat moss, Organic Mechanics Planting Mix Compost Blend, Organic Mechanics Premium Blend Potting Soil, PittMoss Prime cellulosic fibers and Organic Mechanics rice hulls. The hulls are a substitute for perlite. (Wendy Galietta/The Washington Post)
For horticultural use, the extraction of peat requires the removal of a bog’s living surface to reach the partially decomposed layers beneath. It grows at a mere sixteenth of an inch a year, and its mining removes layers that take centuries to develop. “Peat is the best vegetative carbon sink we have on the planet,” Highland said. “Why dig it up?”
Highland developed peat-free mixes for seed starting, containers and general soil amendment, and he thought sales would “go through the roof” as gardeners around the world began to equate peat moss use with global warming.
In Britain, for example, using peat has become taboo. The government’s environmental agency has said it wanted to phase out peat moss for hobby gardeners by 2020 and commercially by 2030. The London-based Royal Horticultural Society, the largest gardening organization of its kind in the world, has reduced peat use by 97 percent at its four major gardens and urges its members to follow its lead.
Highland, whose products are carried by Whole Foods Market, says he has seen steady growth in the past decade but not the explosive growth he and others had expected. On this side of the Atlantic, the ecological arguments against peat moss have been far more muted. Whatever the reasons, the issue has not seeped into most consumers’ consciousness.
“I think the average gardener has no idea what peat moss is, where it comes from and whether they should even consider an alternative,” Highland said.
Of the hot-button issues seen by Sally McCabe, who manages educational issues for the Pennsylvania Horticultural Society, peat moss concerns pale next to others. “The biggest is probably Roundup,” she said, referring to the controversial herbicide. She counsels members to minimize peat moss use. “I always push the renewable stuff, particularly locally sourced,” she said.
Canadian peat producers say that the mining is sustainable and that harvested bogs are returned to living sphagnum moss peatland after five years. (Quebec Peat Moss Producers Association)
In northern Europe, dried peat has been used for centuries as fuel — raising its profile as a source of atmospheric carbon dioxide — and people live closer to ancient bogland that has been drained for agriculture and development. In Canada, by contrast, peat isn’t used as a fuel, and its sheer acreage in less populated areas works in favor of its mining. Canada is the second-largest country on Earth and has 25 percent of the globe’s peatlands. The bogs are drained before harvesting, and the top layers of peat are mined with a large vacuum apparatus.
Peat producers make a persuasive argument that they are harvesting sustainably. (Canadian environmental groups I contacted had no position on peat moss.)
The Canadian Sphagnum Peat Moss Association, representing 14 major producers, says that the industry has harvested approximately 73,000 acres out of 280 million acres of the country’s peatlands and that the amount taken each year is a fraction of the quantity that is naturally generated in undisturbed bogs.
Paul Short, the group’s president, said that for the past 10 years, producers have been restoring harvested bogs by allowing them to re-flood and seeding them with shredded moss grafts that grow and knit together. The moss covers the harvest site within five years, he said, and the bog is “back to a near-natural condition within 10 to 15 years,” he said.
The argument is convincing to horticultural growing media producers such as Karl Hammer, who uses Canadian peat moss in the mixes he makes for commercial greenhouse growers and others. “Obviously, it’s a resource that has to be used respectfully, but I don’t see it going away,” said Hammer, president of Vermont Compost Co. “We should focus on using less gasoline, not less peat.”
Highland is unswayed. “There are many ways to argue what’s sustainable,” he said. “Any forest is sustainable if you plant more trees,” but the original old growth trees are gone, he said. A mined peat bog “is never going to return to its former self,” he said.
If you believe that using less peat is a good thing, you may want to reserve your peat consumption to container use and seed starting rather than the soil amendment and lawn work, which consumes larger quantities. Because of its low pH, peat is still a go-to amendment when planting acid-loving plants such as heathers, azaleas, blueberries and pieris.
For general soil improvement, I use mixtures of compost and leaf mold, either homemade or commercially produced. This meshes with the Royal Horticultural Society’s advice. “We believe that using peat for soil incorporation and ground mulching is unnecessary and unacceptable,” spokesman Garfield Myrie wrote in response to an email.
As a growing mix, peat doesn’t need a lot of company. Pure, compressed bales of sphagnum peat moss are sold to consumers, but in mixtures for containers and seed starting, peat moss is generally blended with inert minerals to improve its moisture- and nutrient-holding qualities: perlite, a volcanic glass, or vermiculite, a mica. Both are expanded by high heat. Typically, lime is added as well to raise the pH. One drawback is that if peat is allowed to dry out, it shrinks and is difficult to re-wet.
Alternatives to peat tend to be more heavily blended with one another to achieve peat moss’s desired qualities.
Compost: Compost is made from rotted plants, green waste and animal manures. It is inherently renewable, and making your own is cheap and minimizes your carbon footprint (no shipping). The rub is that compost takes time and skill. Authentic compost is a careful blend of nitrogen and carbon sources, turned frequently, kept moist but not wet, and screened for use — all reasons to buy high-quality bagged compost. Most backyard compost piles are merely aging piles of organic matter that don’t get hot enough to kill weed seeds or pathogens.
Coconut fiber: Coconut fiber, called coir, is a byproduct of fiber processing and has become a favored alternative to peat moss over the past 20 years. India, Sri Lanka and Vietnam are centers of production. It has the same water holding and porosity of peat moss, though it is generally used as one ingredient in a mix.
Its distant origins raise questions about the carbon footprint of its shipment to the United States. In addition, it derives from coconut plantations that may have been carved out of rain forests, Short said. “Yes, it’s a byproduct, but this isn’t Tom Hanks wandering around an island picking up coconuts,” he said. “These are plantations.”
Pine bark: Finely shredded and composted pine bark (not pine nuggets, pine needles or pine mulch) is a valuable substitute for peat moss as part of a mixture.
PittMoss: PittMoss was created by an inventor in Pittsburgh and consists of reconstituted paper fibers with added proprietary ingredients. It can be used alone or mixed with potting mix, based on the product used.
Rice hulls: Sterilized rice hulls are not a substitute for peat moss but replace perlite and vermiculite, the production of which requires fossil fuels.
Worm castings: This is the waste from farmed earthworms, rich in nutrients and beneficial microbes, and used as a common ingredient in peat-free mixes.
@adrian_higgins on Twitter