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Peat Moss or Compost

By Dana Hall McCain ; Updated September 21, 2017
Organic amendments enrich garden soil.
bêche image by Claudio Calcagno from Fotolia.com

Even in gardens where other fertilizers are used, enriching the soil with organic matter like compost or peat moss can improve your chances of horticultural success. Aside from boosting the nutrient content of your soil, these amendments can also improve soil texture and water retention. But some gardeners are stumped as to which soil amendment to choose for their particular garden.

Compost and Peat Moss Defined

Compost is the decayed remains of natural things like lawn clippings, food waste, manure or leaves. It can be purchased, but many gardeners have taken to producing their own compost in a bin. When organic waste is piled in a bin and given the proper conditions with regard to air and moisture, it slowly breaks down into a rich, black substance. The composting process takes around 90 to 120 days.

Peat moss, by contrast, is partially composted moss harvested from prehistoric non-renewable logs. It is light and highly absorbent, retaining 10 to 20 times its weight in water.

Improving Moisture Retention

If improving the moisture retention of your garden is a primary concern, peat moss may be the best choice. It's highly absorbent characteristics outperform compost in this respect. However, since the surface tension of peat moss makes it water-repellent when dry, it's not a great choice for mulch or top dressing.

Nutrient Content and Acidity

When it comes to boosting the nutrient content of soil, compost is a better choice than peat moss. Compost contains far more nutrient value and releases it slowly, benefiting your plants over a longer period of time.

Many gardeners also prefer compost because of its relatively low acidity. With a pH that hovers between 6.2 and 7.2, it's far less acidic than peat moss. Peat moss, however, is a good choice for working into beds of acid-loving plants like blueberries and azaleas.

Enhancing Aeration

Both peat moss and compost have the ability to improve the aeration and consistency of your soil. This allows oxygen and moisture to reach your plant's roots easily, and for those roots to grow. Both organic materials are known for improving soil structure, but peat moss may give longer-lasting improvements in this area, as it decomposes more slowly than compost.

Choosing the Best for Your Garden

To make a final decision regarding the soil amendment that is best for your garden, assess the condition of your current soil. A soil test will be of great benefit in this process. You can obtain a soil testing kit from your local agricultural extension service office. Collect and submit a sample of your soil according to the directions, and the laboratory will analyze the sample and send a report to you detailing its nutrient content and other characteristics.

Additionally, take into consideration the type of plants you'll be placing in the area, and their typical needs in terms of nutrients and acidity.


About the Author


Dana Hall McCain is a freelance writer based in Dothan, Ala., and is a a regular contributor to numerous regional publications. She writes features and columns on a variety of topics, including the outdoors, faith and health/wellness. She received a Bachelor of Arts from Auburn University in public relations/communication in 1995.