Peat Moss as a Source of Organic Matter

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Peat moss, for the home gardener, is one of the most convenient sources of organic matter.  It doesn’t require any further decomposition or composting; it can be applied immediately to any garden.  Peat moss is also sold in tightly packaged bales at pretty much any store that has a garden center such as Walmart, Lowe’s or Home Depot, or a local nursery.

The fact that it comes packaged is a marvelous convenience in and of itself: you don’t have to own a truck to haul it, or have to pay for somebody else to haul it to your house. Packaged peat moss can fit in the back seat of your car or in the trunk. Peat moss is often processed; check the label to be sure. That means that it is sterilized to kill any pests that may have been in the peat moss such as fungal diseases or weed seeds. The sterilization process also tends to remove nutrients from the peat moss so unless the package label says that the peat moss has been enriched, you’ll need to add some nutrients of your own with organic fertilizers, compost, or compost tea.

Don’t be confused by this last point. The peat moss, as a source of organic matter, still has an enormous nutrient holding capacity.

Herein lies an important concept about organic matter that I probably ought to expand on a little bit while I’m on the topic. Organic matter has a very large nutrient holding capacity. Note the word holding

Organic matter does not necessarily provide the nutrients itself, so much as it just holds on to nutrients in great quantities so plants’ roots have a chance to reach them. A good analogy for this phenomenon is likening organic matter to a bank.

A bank has a large capacity to hold great sums of money but that doesn’t necessarily mean that the bank actually has money in it.  The bank’s vaults may have lots of space and open shelves to hold money but those shelves may be completely empty. And so it is with organic matter: it holds and stores nutrients very well but does not necessarily provide the nutrients in and of itself.

Now, having said that, there are a lot of different kinds of organic matter that come with their nutrient holding capacity already full of nutrients. In fact, most organic matter sources come loaded with nutrients. But that’s not always the case. Other sources of organic matter come with their nutrient holding capacity not so full, and sterilized peat moss in an example of this.

Peat moss also tends to be acidic. This can be a benefit or a drawback depending on where you live.  In the Intermountain West of the United States or in other arid regions of the world where soils tend to be alkaline, adding acidic peat moss will really benefit your garden. In the Eastern United States or other humid regions around the world where soils are already acidic, adding an acidic peat moss will not help out with your soil’s pH. But fortunately correcting acidic soils is fairly easy; easy enough that I personally still consider peat moss a good organic matter source for even acidic soils. And I’ll explain how to correct soil pH and all whys and hows concerning soil pH in another podcast.

One other thing I need to mention about peat moss is that it is commonly a more expensive option for organic matter because it is a non-renewable, mined product. Peat moss is mined from peat bogs, processed, and then shipped across the country to the market place.

Now, for the home gardener, where gardens are not that large, the greater expense is usually not that significant. For larger operations, economies of scale would dictate that the greater expense would amount to a significant cost to the point that other organic matter sources would be a better economical choice. But for smaller gardens, the greater cost is usually not that big of deal. If you’re on a tight budget, don’t worry, there are still a lot of organic matter sources that are easy to get your hands on, that are totally free. To learn more, check out some of our other podcasts on compost, organic matter, soil pH, and everything else you need to know to be a successful gardener.

I want to add a final note: I do not recommend peat moss as a rule. However, for beginning gardeners or for people in apartments or other urban dwellings with limited resources, peat moss is an easy way to get started in gardening. It is probably only for these purposes that I would actually ever recommend peat moss. I would rather someone begin gardening by buying a package of peat moss, than to never begin at all.

Be sure to check out our podcasts on different types of organic matter and their uses in the garden.

Green Composts 

Vermicompost and No-Till Gardening 

Organic Matter 

Brown Composts

Brown Manures

Green Manures

 and Top 12 Gardening Mistakes

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4 Responses to Peat Moss as a Source of Organic Matter

  1. Mike nelson October 27, 2015 at 1:17 pm #

    I realize that peat moss is non renewable but do you know how much carbon it releases in the air?

    Reply
    • Anni November 17, 2015 at 8:38 pm #

      It would only release carbon in the air if it is burned. Otherwise, it pulls carbon from the air, as plants do, during photosynthesis.

      Reply
  2. Tirthankar September 29, 2016 at 4:52 am #

    Hi Anni,
    Greetings!!
    Thanks a lot for the information on peat moss. I am a plant biologist from India and have been researching on nutrient deficiencies in plants.I would really appreciate if you may please illuminate me on the following aspect regarding pet moss:

    In this regard, I need to grow millets in a soil-less substrate (registered name – soilrite mix) which contains perlite,irish peat moss and vermiculite in the ratio of 1/3:1/3:1/3. The mandate of the experiment requires me to use a substrate which is inert (devoid of any nutrient) so that I can examine the effects of specific elements on plant growth and yield. The problem is that although perlite and vermiculite are known to be completely inert, i am not sure about peat moss. After reading through your article, I understand that peat moss is not necessarily a nutrient source but rather a conveyor of the same received previously through fertigation. Could you please provide more information on the chemical composition of peat moss so that I can have an estimate of how much (if any) can potentially leach out in during fertigation to plants.

    Many thanks.

    Tirthankar

    Reply

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