Agriculture Reference
In-Depth Information
Carbon and Nitrogen
We loosely categorize our materials as being carbon materials and nitrogen materials.
Carbon materials tend to be yellow-brown and dry, so they're often referred to as
“browns.” They can have anywhere from a 30:1 carbon to nitrogen ratio to hundreds of
times as much carbon as nitrogen. Nitrogen materials tend to be wet and often green, so
they're often called “greens.”
Despite the “greens” name, they still have more carbon than nitrogen, but the ratio is
generally much lower — between 10:1 and 30:1. Just because something is actually brown
in color doesn't mean it's necessarily a high-carbon material. Chicken manure, for ex-
ample, is definitely a “green,” though if it actually looks green you should check what
you're feeding your chickens.
Carbon materials, roughly in order of increasing carbon content, include leaves, straw,
hay, paper/cardboard, and wood/sawdust. Nitrogen materials, roughly in order of increasing
nitrogen content, include manure, seaweed, grass clippings, alfalfa hay and food scraps, al-
though manure varies depending on the animal and the freshness. In reality, all of these ma-
terials vary based on different factors. Kitchen scraps, for example, can range from being
high in nitrogen to a moderate 25:1 carbon to nitrogen ratio. You can find many reference
charts online with carbon to nitrogen ratios for common materials. It's worth checking
more than one, since they don't always agree with each other's estimates.
