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Using Forest Soil to Inoculate Compost

by Haydn Gunningham
(Perth, Western Australia)

I like to add a couple of buckets of forest soil prior to making my hot compost. I use a hot composting technique and my pile is usually about two cubic meters in volume. I compost in the range 55 to 65 degrees Celsius. Does this temperature wipe out the mycelium that I have introduced? If so, do the introduced fungal spores survive this temperature (and turning activity) and spring back to life at the lower temperatures?


PS – Great site!

Our Answer

I wanted to change things up tonight, so I decided to reply to Haydn’s question in a video post.

As I mention in the video, I sent this question to my friend Dan from Symbio, a leading manufacturer of compost tea products and other soil biologicals in the UK. He then passed it on to his senior biologist, David Ward, who provided us with the following answer:

“If you are taking fungal dominant biology from a mature forest soil and adding it to the start of a high heat composting process, the chances are a lot of the biology will be killed off due to it being put in an environment it is not adapted to. There will probably be some fungal species that will survive and some spores will probably remain viable but I would have thought you would get a better result from adding forest soil at the end of the process rather than the beginning”

Makes a lot of sense, doesn’t it?

Imagine being ripped out of your warm bed in the morning and thrown into a freezing cold shower. Doesn’t sound very pleasant, does it? Well, take your reaction and magnify it several hundred times and that’s what we’re doing to the soil microbes in this example.

Thanks so much for your reply Dan and David. Our Compost Tribe salutes you. To learn more about Symbio, please visit their website below.

Symbio – Bringing Life To Your Soil

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