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Peat Moss & Pine Bark Issues


Peat moss is anti-microbial. Microbes don't grow well in it. That's just the opposite of what we want. Peat moss is good for storing bulbs or shipping food or other live material. Potting soil should NOT BE STERILE as some recommend, but alive and dynamic. It should be light, well aerated, full of microorganisms and have the ability to stimulate quick and sustained growth.


Pine bark is not good for plant growth. As it breaks down it forms some natural chemicals such as phenols and turpenes that inhibit plant growth. It has been established in university tests that it does not support many of the beneficial microbes that prevent disease. 


Peat moss problems: 


Over 10 million cubic yards of peat moss are harvested each year in Canada and another 1 million cubic yards in the U.S. It takes about 1,000 years for a one yard thick layer of peat to accumulate. Peat grows on the surface of the bog where there is oxygen. As the plants die, they settle to the bottom where there is very little if any oxygen (anaerobic) and slowly decay, forming thick mats of partially decomposed plant material.


Carbon cycle diagram by Kevin Saff, via Wikimedia


For more, read in the New York Times about the "world's best carbon sink." Meet Peat, the Unsung Hero of Carbon Capture

More than 90% of the extremely valuable wetland peat bogs in England and New Zealand have been destroyed by the mining of peat. Many countries now prohibit or have placed severe restrictions on the mining of peat wetlands and the sale of peat moss.

Another helpful site is the Bogology, that shares a lot of the science behind the importance of peat (they hosted the graphic above).


Pine Bark Problems:


From the San Francisco Chronicle's SFGate Gardening site, Pine Bark Mulch Problems 

When used constantly over several years, though, pine bark mulch can change the soil pH and use up nitrogen, affecting the growth of small plants. Additionally, during heavy rainfall, the largest particle sizes of pine bark can be unstable, warns Clemson Cooperative Extension. There's also a small danger of spreading pine wilt via pine bark mulch.





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