Product Brochure

15
FIGURING YOUR
CARBON/NITROGEN RATIO
Measure the materials you are using and how many “parts” or common
measurements of each you are starting with. If you have two bushels of grass
clippings and one bushel of sawdust, then you have two “parts” of grass and one
“part” of sawdust. (So would the person who had two gallons of grass and one
gallon of sawdust.)
Now, figure the Total Carbon Value of your mix by multiplying the carbon value
of each ingredient by the number of parts, then add the totals of all materials.
For example:
110 gallons (420 liters) of fresh grass clippings x 6 Carbon (see table)
= 660 gallons (2520 liters)
28 gallons (105 liters) of sawdust x 34 Carbon (see table)
= 952 gallons (3570 liters)
Total Carbon Value = 1612 gallons (6090 liters)
Now, figure the Total Nitrogen Value in the same manner:
110 gallons (420 liters) of fresh grass clippings x .40 Nitrogen (see table)
= 44 gallons (168 liters)
28 gallons (105 liters) of sawdust x .08 Nitrogen (see table)
= 2.24 gallons (8.4 liters)
Total Nitrogen Value = 46.24 gallons (176.4 liters)
Divide the Total Carbon Value by the Total Nitrogen Value to get the Carbon/
Nitrogen Ratio:
Carbon 1612 gallons (6090 liters)
Nitrogen 46.24 gallons (176.4 liters)
The Target Ratio for hot composting is between 25 and 35.
FORMULA NOT QUITE RIGHT?
If you use the formula to get a C/N ratio and the ratio falls outside
of the target area, it is easy to fix your recipe:
If your C/N ratio is lower than 25:1, your recipe is too low in carbon. Add
additional “parts” of a material high in carbon to your formula until your C/N
ratio is between 25:1 and 35:1.
= 34.5 C/N Ratio
LIST OF VALUES
All materials contain both Nitrogen
and Carbon. Materials high in
Nitrogen will also contain some
Carbon; materials high in Carbon
will also contain some Nitrogen.
When you calculate your C/N
ratio, use both the Nitrogen and the
Carbon values for each material.
If no value is listed then it is not a
significant amount and will not be
part of your calculations.
Carbon Nitrogen
Value Value
per 100 per 100
Material grams grams
Fresh grass
clippings 6 0.4
Fresh weeds 6 0.3
Dead leaves 24 0.4
Newspaper 36 0.2
Fruit waste 8 0.2
Kitchen waste 8 0.5
Sawdust 34 0.08
Chicken litter 25 2.5
Straw 36 0.4
Cattle manure
(fresh) 0 0.4
Blood meal 0 16
Horse manure
(fresh) 0 0.7
continued on next page