How to identify quality compost

 
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Molly
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How can we identify high quality compost?

I’m working on building my compost piles but I need to purchase compost to begin the season. What are some things to look for when deciding what compost to buy? Thank you!
TomF
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Ask them what the fungal to bacterial ratio is of their compost. If they can't tell you, you may just be getting anaerobic organic matter that has gone through a waste reduction process. It does not want to be black as that is a sign of anaerobic breakdown. You want to see dark chocolate brown colour for good aerobic compost. It should not be steaming as that is a sign it is not finished yet and will be too hot. Compost that has finished its main biological breakdown and has reached ambient temperature may have a pretty good soil food web present but will likely lack in fungal biomass as fungi take time to do their work and grow. The bacteria are the first to party in the pile and breakdown the high nitrogen materials fast but the fungi who do the breakdown of the more complex carbon rich materials are not so fast so aged compost will have a much higher Fungal to Bacterial ratio. So if you see a lot of chunky but not to woody bits in there still, it may be cooled off but need some time with worms to help further breakdown of the organic matter. Worms don't like hot compost but will tolerate a slightly active compost still.

Charles Dowding, a veteran market gardener, writer and YouTube gardening guru will do seeding tests with new compost he gets compared to a growing medium he knows to see if it is doing better or worse that the incumbent. This way he can taste before committing it to his garden beds. This is a veteran move too though so you need the context of a good start mix to begin with.

Once you find a good source, like Andrew, you will know.

Best is to access it with a microscope for the full soil food web, but that is another story of commitment.
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Andrew
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Molly wrote: Sun 06-Mar-2022, 09:08 How can we identify high quality compost?

I’m working on building my compost piles but I need to purchase compost to begin the season. What are some things to look for when deciding what compost to buy? Thank you!
- Age: great compost starts at 12 months, anything older may still be useful but it won't be considered great.
- Ingredients: is this made from human waste (biosolids is what they call it)? I would avoid anything made from human waste.
- Method: was this made using rapid turn windrow style composting? This will mean its bacterially dominant
- Ingredients: does it have added trace minerals and elements? Any compost that has included sand, clay, silt, rock dust, or other things will mean that its going to have good minerals which is critical when building raised beds and containers especially. Not as critical for top dressing beds that are already connected to the ground.

We will have weekly zoom meetings on composting through March and April, and we will address this topic in the next meeting on Monday. Look for an e-mail coming from Damien.
Jason
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Anyone one know where I can get good quality compost in the Chilliwack BC area? I just learned that the compost I was currently using in made from Cedar.😬
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