The Real Dirt on Peat Moss

by Guest Ranter Ken Druse

"Do you know what sphagnum peat moss is? Do you know what it's used for?"

I asked several gardeners these questions after a lecture I gave in Connecticut a while back. Here are the results of my informal poll.  Fifteen out of 20 people did not know what peat moss was, including the manager of a garden center. (He thought it was the same as homemade compost.) Perhaps more surprisingly, seven out of the 20 people did not know what peat moss is supposed to be used for (although they all bought it). One person said her husband spread it on their lawn. Most of the gardeners suggested that peat moss was a mulch to put on top of the soil.

Peat moss is the partially decomposed remains of formerly living sphagnum moss from bogs.  Because it's nearly impossible to rewet once it's dried, it repels water and makes a terrible surface mulch.  As a soil amendment, which is what the baled product is mostly sold for, peat moss is also a poor choice.  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.

Peat moss is mined, which involves scraping off the top layer of living sphagnum moss. The sphagnum peat bog above the mined product is a habitat for plants like sundews, butterwort and bog rosemary, as well as rare and endangered animals like dragonflies, frogs and birds, not to mention the living moss itself.  Despite manufacturers' claims that the bogs are easy to restore, the delicate community that inhabits the bog cannot be quickly re-established.  Yes, peat moss is a renewable resource, but it can take hundreds to thousands of years to form.

Like all precious wetlands, peat bogs purify fresh air and even mitigate flood damage. 

And there are archeological reasons to preserve peat bogs.  In the acidic moss below the living layer, wooden artifacts of people who lived long ago survive, even the remains of the people themselves.  CO2 is also preserved – trapped in the moss, but released into the air when mined. In fact, peat bogs store about 10% of all fixed carbon.

In the U.S., peat moss is almost exclusively used by the horticulture industry. 40,000 acres of sphagnum are currently being harvested in Canada, with 90% of the product destined for gardens in the U.S.  In the U.K., where peat moss is burned as fuel, as well, nearly 94% of the lowland bogs have been altered or completely destroyed due to harvesting.  And most of our peat is shipped hundreds of miles, often when it’s wet and heavy, which adds further to the fuel required for shipping.

Many conservationists, gardeners, and wetlands scientists in these countries have recommended a boycott of peat. The Royal Horticultural Society hopes for a 90% reduction by 2010.  Areas in Ireland have already banned the harvesting of peat moss altogether.

Producers in both Canada and the United States maintain that they never cut sphagnum faster than it grows, and leave behind enough peat to ensure regeneration. The Canadian Sphagnum Peat Moss Association claims that peat-moss operations keep the bogs from being drained for development, that five to ten years after harvesting, the bog will be a "functioning wetland" again, and that after 25 years, 90 percent of the original flora will grow back.  I have my doubts. Some wetlands scientists point out that a managed bog lacks the biodiversity of the original bog.

In a development at the center of the gardening world, Monrovia Growers has just introduced a new line of bagged “soil” which contains peat moss.  That's according to their press release about the products; the word “peat” never appears on their website.

Though gardeners seem to have been programmed to buy peat and are as loyal to the product as some car-buyers used to be about their beloved Pontiacs, there's simply no need to use it. Chopped leaves make a much better and more attractive mulch, and compost is superior as a soil amendment.

If only more Americans could be encouraged to compost.  If only corporations started their own composting facilities, and if only more municipalities got serious about composting.

In addition to homemade compost, I use coir, a byproduct of the coconut processing industry.  (Here's one reliable source.) This formerly discarded material can be shipped completely dehydrated – very lightweight – which reduces its energy requirements for transporting. 

What do other organic gardeners think about peat moss, coir, or about Monrovia’s new products?

This week on the radio show "Ken Druse Real Dirt," Ken interviews Tovah Martin. It'll be available  tomorrow right here.
Canadian peat bog photo credit.

Comments

[sarahammocks]

Thank you, Ken, for this thorough and clear explanation of peat moss. I use peat moss to make hypertufa pots, but I would like to stop using it. I have heard coconut coir is a good substitute. (yeah, I know cement is not exactly a green product either, but I think peat is far worse) I am surprised that many organic garden writers still advocate the use of peat moss as a potting mix, and don't mention that it is nonrenewable resource.

[kate]

I hope every gardener gets a chance to read this. Thank you, Ken.

[Rebecca]

I am glad I didn't buy any peat moss. I had touched it before and thought, "I don't need this in my dirt" not that I knew what it was, not really at least.

[Cameron (Defining Your Home Garden)]

I appreciate the awareness that you raise. My son is an archaeologist and my husband has a forestry background. It's only coincidental that I have never intentionally purchased peat since i've been gardening for 30 years. But, your point about bagged "soil" does raise questions about what is in the bag of garden soil that I sometimes buy when I don't need dump trucks of good, organic soil brought in. Or, when I buy bagged potting soil. I will make it a point to read the ingredients more carefully, but we will only know if the manufacturers are honest about what's in the product.

Thanks,
Cameron

[Norah]

Amen!! I never cease to be surprised at the number of people buying peat when it's the worst thing to add to their heavy clay soil.

[judybusy]

Thanks so much for posting this! In my first year as a gardener, I followed the advice of some article and dug in a bale of peat moss. I did so with some guilt, as I knew it came from bogs _and it just can't be a good thing to dig those up, can it?_ It made the soil brick-like for two years, and I never did it again. That was also the last year I double-dug anything!

[Adrian Thysee]

Thanks for this article. I have long since stopped using or recommending peat moss as a soil amendment and I now recommend regular mulching with leaves or compost. Mushroom 'manure' is also great for gardens.

[d_2]

when would peat moss be good to use?

[David]

I off the stuff! I used it on my square-foot-gardening beds because that's what Al recommended.
I will find another way to acidify the soil for my blueberries.
I wished my garden centers would carry coir as readily as they carry sphagnum peat moss.

[Victoria]

Thanks so much for this- I've known about peat moss for over 15yrs and stopped using it. But so few people seem to know much about any kind of soil amendment. Except of course, real farmers.

I also wish someone would do a post on the dangers of chemical lawn herbicides. The suburbs get inundated with these toxic sprays in the spring- it would be great to have a zoning ordinance against them!

[Shanna]

Thank you for tweeting about your post and the awareness that it brings. Retweeting and you've inspired me to get more serious about composting - not that I've used peat moss, but am guilty of buying bagged soil & mulch.

[mr_subjunctive]

Peat moss is also a leading cause of houseplant death. It has a tendency to stay overly wet for a long time, and then all at once becomes a water-repellent brick which can only be re-wet with great difficulty. Neither state is good for plants. Miracle Gro potting soil appears to be approximately 140% peat moss.

It's a bane of my personal existence, too, because a lot of the plants we get shipped to us from Florida are potted in something which is mostly peat, which makes watering at work even trickier and more problematic.

It does have one positive use: if not too finely chopped, it's the best medium I've found so far for rooting Cryptanthus (http://plantsarethestrangestpeople.blogspot.com/2008/12/scarecrow-cryptanthus-cvv.html) offsets, which are painfully slow to do anything in soil but which seem to root quickly and well in sphagnum.

[trey]

We carry coir as a substitute for peat moss. Peat still outsells coir, either because people like what peat does for their potting soil, or they don't know about coir. Peat is generally acid reacting so it's great for acid loving plants like blueberries or azaleas. Coir is neutral, and I have had a couple of people tell me that is why they like coir. No one in our area uses peat moss as a soil conditioner. It's use is almost always for seed starting, and container mixes.

Monrovia's website focuses on what they think is important in their "soil". The ingredients for all soils are listed on the bag, from the most used to the least. Peat moss is there, just like most quality potting soils. The lack in mentioning peat in their website is not unusual in the potting soil world.

Many people focus on the cost of the product rather than what's in it. When people question the price of an exceptional potting soil I use the ingredient list to show why it's better. Just like Monrovia's website say's, "If your mix contains too much sawdust or fresh bark, for instance, you will likely see the leaves of your plants yellowing due to a nitrogen deficiency." That's what makes up the majority of ingredients in many of the cheaper potting soils, sawdust.

So if we are concerned with the depletion of resources, what about the sawdust that is used in many potting soils, and bulk purchased soils? It's use is far more widespread than peat.

Just as you point out that, "Some wetlands scientists point out that a managed bog lacks the biodiversity of the original bog", so the forest where the sawdust originally comes from also lacks that "biodiversity" of the original forest. I also wonder about the coconut plantations where coir is harvested from. Are they bio-diverse? Coir comes from fibers found between the husk and the outer shell of a coconut. The coconut plantation certainly displaced the native flora and fauna of the area they are grown in.

You are correct that compost makes a great soil conditioner, though people growing in containers generally need a potting soil, not compost. Some will make their own, but most buy the bag, and either way they use many of the same ingredients.

I am stunned that the manager of that garden center did not know where peat came from. This might explain why peat moss is used so often where is shouldn't be, in the ground. Perhaps through education we will be able to steer people to better alternatives for their situation, and thus avoid the depletion of the peat bogs. It's not the use of peat that is bad. It's the mis-use of peat in situations where it is unwarranted that causes problems.

[keewee]

I also do not like peat moss. I started using coir last year and like it.I also use leaves to mulch.

[Xris (Flatbush Gardener)]

I last used peat moss about 20 years ago. My reservations about using coir is the carbon footprint of transporting it from the other side of the world.

I prefer compost. I have four compost bins. I never have enough.

[Elizabeth Stump]

Did I know where peat moss comes from? Yes. DId I know how it's harvested and that it takes a long time to build up a peat bog? Yes. Do I buy peat moss? Yes. Am I aware how it dries like a brick? Yes. Do I use it as am amendment for lighter fluffier soils with vermiculite and perilite to my potting soil? Sometimes when I need to acidify my soil - though I prefer rice hulls if Ph isn't an issue. Why do I keep buying it? Because coir costs $13 for a 10 qt. bag, and peat costs $10 for a 2 cu. ft. bag. So to buy 2 cu. ft. of coir would cost me $67 (actually $66.95 as there are 51.5 quarts in 2 cu. ft. of soil). So I would have to buy 5+ bags of coir at $13 for 10 quarts for a 2 cu. ft. bag of peat that costs $10.

WHEN COIR IS AS CHEAP AS PEAT, COIR WILL FINALLY REPLACE PEAT.

[LauraBee]

Wow. I knew it was dug out of the ground, but "mined" never dawned on me. I knew about the water repellent properties which is the main reason I avoid it if possible.

Ummm .... so if we need to acidify extremely alkaline soil ( because the thought of summer without homegrown blueberries is intolerable ) what should we use ? Preferably something organic. I do not have enough compost to go around, no matter how much yard debris I swipe from the neighbor's green-waste bins.

[Michele Owens]

Great post, Ken. Thank you.

I've noticed that my neighbors seem to think that the only soil amendments with any legitimacy are the ones that come in plastic bags.

People need to understand that they can enrich their gardens with stuff that's right in their own backyards--their own kitchen scraps, fall leaves, manure from the horse barn down the street, composted yard waste.

It's easier, it's better, and it doesn't destroy any bogs.

[Brie]

It's surprising how rampant the use of peat is given the impact its harvest has on ecosystems.

Coffee grounds, leaves, or pine straw are good for acidifying. And while I have no idea how environmentally friendly it is, there's always bagged sulfur pellets. One bag can last a lifetime.

I went through a little peat dilemma when i was briefly into culturing carnivorous plants, since all the information I would read recommended peat mixes. But I've since given that up, although I may eventually get back into it. Have CP enthusiasts been using coir successfully as a substitute?

[Barbara E]

Thank you for your excellent article. For me - whether it is pots, mulch, or garden veggies - compost does the trick.

[Bob Vaiden]

"WHEN COIR IS AS CHEAP AS PEAT, COIR WILL FINALLY REPLACE PEAT."

You mean when the peat bogs have been virtually destroyed, and peat becomes more EXPENSIVE than coir... or simply does not exist.

We are stripping and sterilizing this planet...it will stop sometime relatively soon... one way or another.

[Christina Salwitz]

As a former Nursery worker, I was telling customers this for years! THANKS Ken Druse for writing about this topic. We need to publicize this on a much larger scale.

[Elizabeth Stump]

Yes, Bob. You are correct. When peat bog have been depleted to the point where the price point matches coir, then the "average" consumer will say, "Gee, why is peat so expensive now? Hmm, I guess I'll try coir since it seems to be about the same price point at peat (or is cheaper than peat finally)."

Yes, we are stripping the planet. But it is when a renewable source, such as coir, matches the price point of peat (which has been in the mindset of gardeners for decades versus the relatively new product coir) that we'll stop using peat in the quantities we use today and people will switch to coir. When it comes right down to it, many people don't want to pay the premium price for a greener/sustainable product. Just look at the produce aisle. How many "average" consumers want to pay more money for "organic" produce? Now you see the battle coir has in replacing peat.

[commonweeder]

Great post! You have shown that many gardeners don't know why they buy the products they do - succumbing to advertising or 'what everyone else does.' Educating ourselves as gardeners is a never ending process.

[Jenn]

Thank you! Thank you!

I knew all of that about peat, but never made the connection that peat was sphagnum. Duh!

Thank you for a very informative piece!