[Terrapreta] To compost or not; and some other points

[Frank Teuton]

Just to add one more point: to compost manures sufficiently to meet USDA Organic requirements requires only that the initial C:N ratio be between 25:1 and 40:1, and that the material is heated hot enough for long enough to meet PFRP (Process to Further Reduce Pathogens) standards used in sewage treatment composting.

You can compost in vessel or static pile, where the entire mass of the materials reaches 131 F for three full days...or you can compost in a windrow, turning five times in 15 days with temps reaching 131 F after each turning of the pile. Such material is considered safe, but anyone with any experience in the matter will tell you...it isn't yet compost! However, it is safer than fresh manure and this speeds up considerably the time between application and potential harvest, as there are no restrictions on such materials once heated per regulations. Different crops will appreciate such fresh residues more, and others less...YMMV

For best weed seed destruction 145 F is a better target temperature ( and no, it won't kill every kind of seed, black medic seed can take up to 180F...nature has a bell curve of diversity here as elsewhere.)

Hope this helps someone,

Frank Teuton



---- Original Message ----- 
From: Janice Thies To: Frank Teuton ; Kevin Chisholm 
  Cc: terrapreta at bioenergylists.org 
  Sent: Friday, April 20, 2007 2:12 PM
  Subject: Re: To compost or not; and some other points


  Many thanks to you, Frank, for your very detailed explanations and additions to the previous messages.  I had meant to mention reducing/destroying pathogens and weed seeds as an important function of thermogenic composting and am very glad to see that you made this important point in your reply, along with being aware of the withholding period for vegetables to which manures (composted or uncomposted) are applied.

  Kind regards,

  Janice
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